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Geology 303 

Coastal Systems and Human Impacts

(Text for Geology 303, Coastal Systems and Human Impacts, 

a CSU Long Beach Department of Geological Sciences Course)

Forward

The combination of human population growth and global warming is placing a growing burden on coastal environments worldwide.   There is a lack of knowledge and understanding of coastal ecosystems and processes, both by the general public as well as by decision makers in public office.   This course, Coastal Systems and Human Impacts, will educate you about this critical natural environment and how humans affect it, both directly and indirectly.   Ultimately, it is hoped that you will be able to make well-informed decisions and educate others about our coast.

There are a number of text books that address the processes and features of coastal systems, and to a lesser degree the impacts that people have on these dynamic and delicate systems.   Unfortunately, these texts either offer topic coverage out of balance with our course requirements, or they tend to ramble, providing information well outside of the scope of this course.   That being the case, this "web book" will guide us through some of the many aspects of coastal systems that pertain directly to our course, with a focus on the Southern California Bight which includes the coast of southern California as well as the offshore ocean from Point Conception down to San Diego.  

Much of the information below has been distilled from years of experience working and recreating in southern California's diverse coastal environments, from verbal communications with fellow scientists, and from reading of countless scientific articles and papers.   As much as possible, sources of information are cited, and you are encouraged to evaluate these sources on your own.

This work is copyrighted by Bruce Perry.   Please contact him for permission to use the contents at bperry@csulb.edu .

Click on one of the chapters listed below, or scroll downward to see all of the chapters.

Ch. 1  Introduction to Coastal Systems            

  Ch. 2 Oceanic and Atmospheric Interactions        

Ch. 3  Coastal Processes and Features         

Ch. 4  Classification of Coasts                

Ch. 5  California Continental Borderland             

Ch. 6  Southern California Bight

Ch. 7  Coastal Zone Pollution

Ch. 8  Los Angeles and Long Beach Harbors

Ch. 9 Coastal Ocean Food Resources

Ch. 10 Coastal Zone Recreation, Tourism and Beaches

Ch. 11  Coastal Ocean Mineral Resources

Ch. 12  Wetlands and Estuaries of the SCB

Ch. 13  Global Warming and the Effects on Coastal Systems

Ch. 14  Coastal Zone Management

Ch. 15  Special Topics Related to Coastal Systems

Chapter 1

Introduction to Coastal Systems

Isla Vista / UC Santa Barbara coastal zone, including the Santa Barbara Channel, the shoreline, coastal plain, lagoon, and stream.  Note the swell from the northwest and the close proximity of human development to the shoreline.

Discussion

The terms "coast" and "coastal zone" are used interchangeably for this course.   They refer to a relatively narrow band of Earth's surface where land meets ocean, which generally follows an ocean shoreline.   Additionally, it includes the coastal ocean which is influenced by terrestrial (land) processes, and land which is influenced by marine (ocean) processes.   These interacting processes are the main focus of this book.   The term "coastal system" refers to the varied and complex interactions that take place at the land-ocean interface, and to the constant cycling of energy and material from one component of a coastal system to another in this dynamic environment. 

Consider a common component of a coastal system, the beach face, where waves can gently wash up and down the beach surface, or pound with great force on the sand.   The range in terms of energy released can be tremendous, with small waves pushing sediment ashore to widen a beach, or larger waves pounding the beach face and removing the sand back into the nearshore coastal ocean.   Ideally, this interaction between the ocean and the beach is in a state of equilibrium, with the narrowing of a beach during a storm eventually balanced by the gradual widening of a beach by smaller waves thereafter.   This simple coastal-system example includes the distribution of kinetic energy, from breaking waves against the beach, as well as the movement of sand either onshore or offshore, depending on the ever-changing weather conditions affecting the beach and nearshore water components of the coastal zone.

Components of a Coastal System

Most of the components of a coastal system have been touched on above, but it is helpful to list them together to organize them in our mind.   During the semester, we will learn how these components interact within the coastal system.

A. ocean currents - transport sediment within the coastal ocean, either parallel to shore in shallow water (longshore current) or offshore into deeper water (rip current).   These currents are induced by wave action.   In addition there are variable coastal currents forced by wind or other ocean currents that circulate within the Southern California Bight, the ocean off the coast of southern California, carrying nutrients as well as pollution.

B. ocean waves - are produced locally or remotely by wind blowing across the water surface.   Waves release energy into the coastal zone as they interact with shallowing depths and break.   The explosive rush of water molecules generated by breaking waves forms longshore current, throws sediment into suspension, places water vapor and spray into the atmosphere, and provides a tremendous source of entertainment for people who love to surf or simply watch the waves roll in.

C. tides - are produced by the interplay of gravity and inertia within the Sun-Earth-Moon orbital system, and rotation of Earth about its axis.   Rising and falling of the tides vertically distributes wave energy along a shoreline, and produces currents that are essential for circulating water in bays, estuaries, and harbors.   Chapter 4 includes further details about tides.

The diagram above illustrates that the Moon has a much greater effect on Earth tides than does the more-distant Sun.

This diagram illustrates the somewhat eccentric orbits of the Sun-Earth and the Moon-Earth systems, which determine the severity of tides on Earth.   Note that when solar perihelion and lunar perigee coincide coasts experience higher-than-normal high tides and lower-than-normal low tides.

D. shallow ocean floor - influences how waves refract and break as they begin to feel the ocean bottom.

E. shoreline - also influences the refraction and breaking of waves, as well as the flow of coastal currents.   A straight shoreline (La Conchita coast pictured below), usually sand-rich beaches, will generally experience uniform waves and currents along its length on any given day.   A rocky shoreline (Palos Verdes coast pictured below) is typically non-linear, characterized by small pocket beaches and headlands.   Such a shoreline will experience more complex wave-break and current-flow dynamics.

F. streams entering coastal ocean - introduce terrigenous sediment of all sizes into the coastal ocean, along with dissolved solids (silicon, iron, and calcium), and, in most cases, pollution.   Streams, being freshwater (salinity < 1 ppt), can drastically lower local coastal-ocean salinity.   During high-flow times, San Juan Creek (pictured below) delivers lots of fresh water and sediment into the Pacific Ocean near Dana Point Harbor.

G. marine life - changes ocean-water chemistry by removing ions such as calcium and gases such as oxygen and carbon dioxide from water.   Dying marine life returns nitrogen and organic matter to the ocean, and adds a variety of biogenous sediment to the ocean floor.

H. atmospheric circulation - in the form of onshore wind carries air conditioned by the coastal ocean's surface temperature and moisture evaporated from the ocean over the adjacent land surface.   Such wind flow also drags water shoreward, dampening any coastal upwelling that might otherwise occur.   Offshore wind can carry fine-grained sediment (clay to sand) as well as pollutants out over the ocean where the particles eventually settle onto the ocean surface.   In addition, wind blowing offshore can drag water away from the shoreline, stimulating coastal upwelling and chilling surface-zone water.

 I.  human input - includes land-derived pollutants that enter the ocean via outfall pipes, channels, and streams, as well as airborne particles.    Humans also introduce pollutants into the coastal ocean from marinas and harbors, and from offshore drill rigs.

Coastal System Energy and Equilibrium   (This discussion follows that of Haslett, 2000.)

A. The primary energy sources within a coastal system include the following:

1. The Sun, which unequally heats Earth's surface.   This stimulates circulation of the atmosphere and ocean, and powers the hydrologic cycle.   The diagram below is from NOAA.   Part A illustrates that heat is gained at the equator, and lost at the poles.   Part B shows large-scale convection of air that occurs from the unequal solar heating of Earth’s surface.

2. Earth's internal heat, which causes horizontal and vertical movements of Earth's crust (a.k.a. plate tectonics).   Throughout Earth's history plate movements have repeatedly opened and closed ocean basins, reconfiguring coastlines on a grand scale.   Present- day configurations of continents and their shorelines and continental shelves are products of such slow but large-scale movement.   Heat flow from Earth's interior is due to radioactive decay of elements within the core.

B. Gravitational attraction and kinetic energy (movement) generated between two or more interacting bodies produces inertia, an equal and opposing force to gravity.   Together, the forces of inertia and gravity produce Earth's tides.

C. Fluctuations in energy along a coast can upset the system's equilibrium, either temporarily or for an extended period of time.   The following coastal equilibrium descriptions are derived from Briggs et al., 1997.

1. steady-state equilibrium - variations in energy and coastal processes/features are generally minor and short-term.   For example, the daily rhythm of small and moderate-sized waves pushes sand shoreward, maintaining the width of a beach.

2. meta-stable equilibrium - dramatic and usually temporary alteration in energy level associated with a major storm or tsunami event.   Such powerful occurrences can relocate large volumes of sediment or destroy ocean cliffs.   Human activities can also cause a shift from steady-state equilibrium to meta-stable equilibrium by modifying coastal processes.   However it is initiated, the changes from steady-state equilibrium are short-lived.

3. dynamic equilibrium - gradual but constant change in a coast's equilibrium over a period of many years.   An example of this would be the rising of ocean level and shoreline retreat due to global climate warming.

Note that all coasts experience each type of equilibrium!

D. Coastal-system component interactions determine the state of that system's equilibrium.

1. These interactions within a system are driven by increasing or decreasing energy levels, by rising or lowering of ocean level, or by human activities, causing the system to switch from one state of equlibrium to another.

2. This switching triggers a feedback response within the system.

a. positive feedback - reinforces and amplifies the initial change in a system, rendering a local coastal system extremely unstable until it returns to equilibrium.   An example of this would be the undercutting of an ocean cliff, the collapse of the cliff face, and gradual adjustment to slope/shoreline equilibrium.

b. negative feedback - reduces the impact of switching from one state of equilibrium to another, smoothing the transition and shortening the time required to return to the original state of equilibrium.   Staying with the ocean-cliff analogy, initial erosion of the base of a cliff could be followed by rapid deposition of sediment at the cliff's base, reducing the tendency for the cliff to collapse.

How Land Affects the Ocean

A. streams flowing into the ocean      Land influences the ocean in a number of ways, most profoundly by streams that flow from the land into the ocean.   Streams carry load in the form of sediment (pebbles, gravel, sand, silt, and clay grains/particles), dissolved solids (typically ions such as iron, silica, and calcium, and bicarbonate), and pollutants (ranging from paper and plastic waste to pesticides and fertilizers. The relatively low-salinity "fresh" water of the stream can reduce local coastal-ocean salinity.

1. Larger sediment grains (pebbles, gravel, and sand) will settle rapidly to the ocean floor, to be shifted around by coastal-ocean currents and waves forming beaches and other coastal landforms, or carried offshore into deeper water by turbidity currents.   When this occurs the sediment is permanently removed from the coastal system.   Smaller sediment grains (silt and clay) have much slower settling velocities, so they tend to be carried suspended within the water column for days or weeks before settling onto the ocean floor.   A large suspended load in the coastal ocean inhibits the penetration of sunlight into the water, reducing photosynthesis by plants and algae, and thereby decreasing the overall productivity within that portion of the ocean.   A large suspended load also reduces visibility within the coastal ocean, negatively impacting such recreational activities as diving and swimming.   The photograph below was taken along the southern California coast just north of Ventura.   Note the rip currents and high suspended load in the ocean.

The photograph above shows the boundary zone of normal ocean water and sediment-rich water derived from the coastal zone.

2. Dissolved solids (a variety of ions) originate as chemical weathering breaks down the minerals comprising rocks of the continental crust.   The primary processes of chemical weathering, dissolution and hydrolysis, occur as water and weak natural acids break apart the bonds holding minerals together.   As this happens, the dissolved solids are carried away by ground water and surface water, eventually flowing into the ocean.   Once in the ocean, ions are readily diffused into the water where they can aid in the metabolism and growth of marine organisms, or eventually precipitate as sediment onto the ocean floor.

3. Unnatural solids, chemicals, or heat energy (generally referred to as pollution) are introduced into the ocean by people, either due to carelessness or by design.   The casual toss of a cigarette butt from a car that's leaking oil onto a road can result in both being carried into the coastal ocean by a stream.   Streams can also receive the outfall from sewage treatment plants or from power plants, conveying low-toxicity or unusually warm water into the coastal-ocean environment.   (Note that many sewage treatment plants and power plants along the southern California coast have their own channels or pipes to carry effluent to the ocean, independent of local streams.)   Heavy industry has a history of releasing toxic waste into streams or directly into the ocean via outfall pipes.   This practice is now severely restricted in the United States and most other countries, but pollutants such as DDT and PCB's are still present within the southern California coastal system, trapped within sediment on the shallow ocean floor and gradually leaking out into the ocean above. 

The Los Angeles River, perhaps the most polluted stream in southern California, flows into Long Beach Harbor.

4. During a rainy season or a significant storm event, an abundance of fresh water may enter into the coastal ocean, temporarily reducing salinity.   Most marine organisms can handle this change in the ocean's chemistry for a few days, either by leaving the area or by shutting down their feeding activities and waiting out the event.   The condition is most acute in shallow harbors and bays where the lower-density fresh water is readily mixed by wave or current action, or by propellers from passing ships.   Combined with the restricted nature of the bay/harbor to the open ocean, the sharp drop off in salinity can pose a crisis for benthic (bottom-dwelling) invertebrates that are not highly mobile.

B. offshore wind      Wind blowing off shore can transport fine-grained sediment and pollution well out over the coastal ocean and beyond, from one continent to another.

1. Fine-grained sediment includes tiny sand grains, as well as silt and clay.   A strong offshore wind can carry these grains for thousands of miles, eventually dropping them onto the ocean surface or even on a distant continent.   Such sediment settling to the ocean bottom has little impact on the overall accumulation of ocean-floor sediment, but thin layers of silt and clay can supply evidence for past climate changes which promoted atmospheric circulation conducive to carrying sediment from land out over the ocean.   (Note that sediment grains transported by wind tend to experience thousands of in-flight collisions, pitting the grain surfaces.   The overall frosted appearance of such grains is indicative of sediment carried and deposited by wind.) 

2. An offshore wind also transports aerosols (tiny airborne particles such as volcanic ash, microorganisms, soot from fires, and pollen) as well as air pollution (a mixture of toxic gases and solids) across the coastal ocean.   While suspended in the atmosphere, fine-grained sediment, aerosols, and pollutants can absorb sunlight before it strikes the ocean surface, reducing photosynthesis by tiny marine plants and animals, decreasing the productivity of the coastal ocean.   Some of the pollutants that settle to the ocean floor may eventually bio-accumulate to toxic levels within the tissues of some organisms.    

NASA satellite photograph of smoke from wildfires of October, 2007.   Fire zones are highlighted in red.   Note that these fires were associated with strong Santa Ana winds flowing offshore, transporting a variety of particulate matter out over the Southern California Bight.

How the Ocean Affects Land

A. distribution and deposition of sediment along a shoreline      The combination of waves washing ashore and longshore current, created as waves break at an angle to a shoreline, distribute sediment along a coast.   Sediment introduced into the coastal ocean by streams or by the erosion of coastal cliffs is transported by the longshore current parallel to the shoreline.   Smaller waves, usually less than three feet in height, drag and push sand ashore, widening a beach over a period of months.   Other features such as spits and bars may also develop.

Wide beach along coast of Huntington Beach.

B. erosion of a shoreline      Larger waves, typically greater then three feet in height, release a lot of energy when they break in nearshore water.   During a high tide, such waves will break closer to shore, with the possibility of breaking on the beach face.   This rapidly removes beach sediment, narrowing the beach and the protection it offers coastal cliffs, buildings and other structures.   Large waves generate greater back wash off the beach face, forming strong rip currents which can carry sediment offshore, away from the beach.   Eventual return to smaller waves allows this sediment to be gradually returned to the surf zone and beach environments.

Large, energetic wave breaking at the Wedge, Balboa Peninsula.

C. moderation of coastal climate        Due to hydrogen bonds between water molecules, a lot of heat energy is required to break the hydrogen bonds and then to excite the water molecules, warming a body of water.   Therefore, water has a high heat capacity, which moderates its temperature fluctuations.   (Conversely, land's rocks and minerals, which have lower heat capacity, change temperature much more readily as temperature warms or cools.)   Air above the ocean has its temperature moderated by the ocean beneath it, and in addition it receives water vapor due to evaporation from the ocean's surface.   These factors engender a moderate coastal climate if the dominant direction of wind flow is onshore, which is the case with southern California.

Palm trees along Cabrillo Beach, San Pedro have experienced strong onshore wind flow as they have grown, tilting their tops away from the ocean.

      Conclusion

The features, processes, and environments discussed above will be revisited in later chapters to varying degrees of detail.   This will establish the scientific knowledge base that will enable you to clearly understand how the coastal system affects humans, and how we affect the coastal systems around us.

References

Briggs, D., P. Smithson, K. Addison, and K. Atkinson, 1997.   Fundamentals of the Physical Environment, 2nd edition.   Routledge, London.

Dailey, M.D., D.J. Reish, and J.W. Anderson, 1993.   Ecology of the Southern California Bight: a synthesis and interpretation.   University of California Press, London.   926pp.

Garrison, T., 2007.   Oceanography: An Invitation to Marine Science, 6th Edition.   Thomson Brooks/Cole.   588pp.

Haslett, S.K., 2000.   Coastal Systems.   Routledge, London and New York.   218pp.

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Chapter 2   

Oceanic and Atmospheric Interactions

Discussion

A system consists of two or more interacting parts that together form the whole.   Interactions of these parts causes material to cycle within the system.

Coastal systems, being part of the Earth system, do not operate independently of the vast ocean.   Indeed, most waves and currents which impact upon a coastal zone are usually generated far from shore on the open ocean.   That's why it is necessary to consider the big picture of oceanic and atmospheric interactions, because the products of those interactions can have a major impact on energy and material flow within a coastal system.  

Much of the cycling of material and energy within the Earth system is derived from solar energy.   Within a coastal system, the Sun's energy directly or indirectly drives the natural processes and activities within coastal zones.

Energy Exchanges Between the Ocean and Atmosphere

A. Wind, mass movement within the atmosphere, inputs energy into the ocean as it flows over surface water.   The frictional transfer of energy into the ocean is not very efficient, but it can form:

1. surface currents that flow at approximately 2 to 3 % of the velocity of wind

and

2. ocean waves of variable sizes, with the largest formed where wind blows at high velocity over a great distance, for days at a time.

B. The ocean's stored heat energy warms the overlying atmosphere, influencing global climate and fueling the growth of cyclonic storms that become hurricanes when water is warmer than 79° F.

The ocean warms the atmosphere above by radiation of heat energy into the air, and by the process of evaporation during which water molecules take heat energy with them as they go from the liquid to the gas phase.   (This latent heat can eventually be released as water vapor cools and condenses onto microscopic solid particles suspended within the atmosphere, forming rain drops.   Where this process happens rapidly, such as the windward side of coastal mountains, the sudden release of energy in the atmosphere can fuel powerful wind bursts and lightning.)

Large-Scale Atmospheric Circulation

A. Unequal solar heating of Earth's surface produces convection (vertical and horizontal flow) of the atmosphere.

B. Earth's rotation induces the Coriolis effect on flowing currents (air or water); currents deflect to the right in the northern hemisphere, and to the left in the southern hemisphere.   Together, convection of the atmosphere and the Coriolis effect produce belts of prevailing winds, the Trade Winds, Westerly Winds, and Easterly Winds, that flow across Earth's surface roughly parallel to the equator.

1. Trade Winds - blow from east to west at fairly constant velocity of 15 to 20 miles per hour, driven by equatorward flow of warm surface air in the Tropical Cell.

2. Westerly Winds - blow from west to east with highly variable velocities from 5 to 30 miles per hour, driven by poleward flow of surface air in the Mid-Latitude Cell.

3. Easterly Winds - blow from east to west a with typical velocity range from 10 to 30 miles per hour, driven by equatorward flow of cold surface air in the Polar Cell. 

This diagram illustrates the major convection cells and wind belts that exist within Earth's atmosphere due to unequal solar heating of Earth's surface and Earth's rotation about its axis.

 

Large-Scale Oceanic Circulation

A. Cold, polar climates chill ocean water, increasing its density.   The removal of heat energy allows water molecules to move more closely together, and the freezing of ocean water squeezes the salt ions from the growing ice crystals into the remaining ocean water.   The dense water tends to sink, forming downwelling (thermohaline) currents which flow slowly and for tremendous distances within the ocean at mid to great depths.   Nutrients from the surface zone of the ocean continually rain downward to the ocean floor, enriching the deep currents with dissolved nutrients.  

Thermohaline current circulation only affects coastal systems where wind or surface-current flow is offshore.   This enables the cold, nutrient-rich currents to upwell, chilling the the water and stimulating the growth of phytoplankton, the primary producers of the ocean.   This production attracts lower- trophic level consumers (zooplankton), which in turn attract small and large fish to an area of upwelling.   The western coasts of continents, including the California coast, are zones of upwelling stimulated by the flow of persistent surface-ocean currents.

B. The Trade Winds and Westerly Winds blow across the ocean surface.   Friction between these two fluids of different density drags the surface of the ocean along, forming slow-moving ocean currents that flow at approximately 45° to the direction of wind flow.

1. The Coriolis effect and the physical presence of continents promote the circular flow of wind-induced surface currents around the edges of each ocean basin, forming gyre currents.   Gyres are composed of four individual currents:

a. equatorial current - flows westward between 2 and 6° latitude, parallel to equator; very warm water temperature (80 to 90°F).   example:  North Equatorial Current

b. mid-latitude current - flows eastward between 50 and 58° latitude, parallel to equator; cool to cold water temperature (35 to 50°F).   example:  North Pacific Current

c. western boundary current - flows poleward where equatorial current turns due to the Coriolis effect and presence of continent; flow is relatively deep and high-velocity, and hugs outer edge of continental shelf; warm water temperature (70 to 80°F).   example:  Japan (Kuroshio) Current

d. eastern boundary current - flows equatorward where mid-latitude current turns due to Coriolis effect and presence of continent; flow is broad, shallow, and low-velocity, and in some areas moves over the continental shelf; cool water temperature (45 to 55°F); flow promotes offshore transport of surface water due to the Coriolis effect, stimulating coastal upwelling.   example: California Current

 

               

   This diagram shows the five main gyres of the world ocean, with the South Indian Gyre cut in half by the ends of the diagram.

2. Gyre currents have a profound impact on mid-latitude coastal water temperature, which in large part determines the nature of coastal ecosystems and their attractiveness to human habitation.   Also, gyre currents can stimulate coastal currents and eddies critical to some coastal regions such as the Southern California Bight, as shown in the diagram below.

 

This diagram shows the equatorward-flowing California Current, and eastern boundary current, flowing past the Southern California Bight.   As this occurs, water shears away from the California Current forming the Southern California Countercurrent (SCC), the Southern California Eddy, and numerous smaller eddies which develop as the SCC flows past the Channel Islands.

 

Short Essay      Explain how unequal solar heating of Earth's surface generates eddies within the Southern California Bight.

References

Garrison, T., 2007.   Oceanography: An Invitation to Marine Science, 6th Edition.   Thomson Brooks/Cole.   588pp.

Hickey, B.M., 1992, Progress in Oceanography, V30:37-115.

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Chapter 3   

Coastal Processes and Features

Discussion

To understand a coastal system and how it functions, it is essential that you know how the primary features of the coastal system formed.   Understanding how coastal processes lead to the development of certain coastal features is not only interesting but critical to enabling you to predict what will happen in the near future in a particular coastal zone.   This is the foundation of sound coastal planning for long-term human development and coexistence within the coastal environment.   Furthermore, once you have a solid grasp of the cause-and-effect relationships at work in a coastal system, you can go to any coastal area and quickly discern the dominant processes at play by recognizing features covered in this chapter, and associating them with their related processes.

Dominant Coastal Processes

In a coastal environment, land affects the ocean, and the ocean influences the terrestrial environment.   Therefore, coastal ocean processes and land are interactive with each other.   Listed and described below are the dominant processes at work in a coastal environment.

A. An ocean current is a coherent flow of water molecules generally moving in the same direction.   Coastal-ocean currents transport nutrients, energy, and sediment as they flow.

1. large-scale nearshore and offshore currents - generally flow parallel to the coast; flow is typically related to gyre current flow, or possibly to seasonal wind flow.   An example is the California Current which flows equatorward along the coast of Oregon and California.   Velocity of the California Current increases during winter and spring as south-flowing winds add energy to its flow.   These large-scale currents play a critical role in distributing nutrients and plankton within the surface zone of a coastal ocean.

2. longshore current - flows parallel to the coast, but only within the surf zone (between breaking waves and the shoreline).   Longshore current, formed as waves break and release energy at an angle to the shoreline, are significant because they can transport great quantities of sediment from where it is introduced into the ocean by a stream to beaches up or down the coast.   Observe the waves washing ashore at Bolsa Chica and Huntington Beach in the photograph below.   As the waves  break at an angle to the shoreline and release energy, the resulting longshore current will flow toward the bottom of the photograph.

 

3. rip current - (formerly and incorrectly referred to as "rip tide") flows offshore from shallow surf-zone water.   Rips form where longshore currents or wave backwash collide due to the configuration of the coastal or beach topography.   A strong rip current can carry sediment and swimmers out past the breaker zone.   Shown below are rip currents along Peninsula Beach, Long Beach, California.   Note the plumes of sediment carried offshore by the rip currents, which are more visible in the second photograph.

4. tidal current - forms within restricted inlets to bays and harbors as tide rises, forming a flood current, or as tide lowers, forming an ebb current.   Tidal currents are often the sole means for circulating water within bays and harbors.    View the photograph below, which shows the tidal inlet for Bolsa Chica Wetlands.   Was the tide rising or lowering when this photograph was taken in October of 2006?

 

 

5. upwelling current - the movement of deep, cold, nutrient-rich water up towards the surface, enabled by the horizontal movement of surface ocean water.   Upwelling occurs where surface coastal-ocean water is forced away from shore by an offshore wind, or by the Coriolis effect causing a nearshore current to veer offshore.

 

B. Ocean waves are nearly friction-free wave-form energy capable of traveling great distances within the surface zone of the ocean.   Most waves form as wind transfers energy into the water.   A wave's energy is is typically released within the surf zone as they begin to "feel bottom", slow dramatically, and then break.   (Energy may be released further inland due to a combination of large storm waves and high tide, or due to a tsunami.)

1. swell - waves of fairly equal height, length, and period which form as storm-generated waves become sorted according to size and period as they move away from the storm's center.   Swell, in the photograph of the Oceanside, California coast, can travel thousands of miles before breaking along a distant shore.

 

2. local wind waves - generally smaller and less organized than swell, local wind waves can be superimposed onto swell, making the ocean surface chaotic.   Surfers dislike these smaller waves, referring to them as "wind chop", because they mess up the uniform swell waves.   The photographs below show Long Beach Harbor on a breezy day, with small locally formed wind waves, and no ocean swell.

 

3. wave interference - the interactions of two sets of swell can result in waves much smaller than usual (destructive interference) or much larger than usual (constructive interference).   (The latter possibility can form dangerous rogue waves on the open ocean, or so-called "creeper waves" along a beach.)   Wave interference can also occur where an incoming wave reflects off of a jetty.   The reflected wave can then interfere with the next incoming wave to form a peaked wave of great height, such as the Wedge at Newport Beach shown below.

 

4. wave refraction - occurs as as a portion of an incoming wave begins to interact with the ocean floor, slowing some of the wave and bending it in one direction or another.   This can focus a wave's energy on a submerged reef, forming an excellent surf locale such as Jaws off the coast of Maui, Hawaii.   More typically, the wave's energy is focused on a small rocky island (stack) or a headland that juts out into the ocean.   This photograph shows the refraction of waves as they enter Bluff Cove along the shore of Palos Verdes Peninsula, California.

5. wave diffraction - an obstacle (island or breakwater) forms a new point of departure for a wave, spreading the wave's energy over a greater area.   This occurs because the obstacle creates a wave-shadow zone behind it, with propagating waves spreading laterally with diminished size and energy.   This process is significant for waves moving through the Southern California Bight, as illustrated by the wave shadows created by the Channel Islands in the Scripps coastal data diagram below.

C. Given time, a shoreline with multiple embayments and headlands will become fairly straight.   This long-term process requires a combination of ocean current and wave action, which erodes headlands and fills in embayments with sediment.   For shoreline straightening to transpire, tectonic uplift must be absent.

 

Coastal Features

Generally speaking, coastal features are classified according to the dominant processes at work along a coast - either erosional or depositional.

A. Depositional coastal features require an abundance of sediment, and adequate energy to move the sediment around within the ocean.   Listed and described below are some common coastal features formed as sediment settles from coastal currents and waves.

1. beach - is usually composed of sand-sized sediment which is deposited a short distance inland as well as offshore.   Beaches are formed by a combination of longshore current, which transports sediment parallel to shore within the surf zone, and wave action which bulldozes the sediment shoreward.   Capistrano Beach, California, shown below, receives sediment carried from San Juan Creek by longshore current.   "Capo" Beach is notorious for its rip currents, indicated by the plumes of sediment in the photograph.

 

2. spit - an elongate buildup of sediment that develops as a strong longshore current carries sand and silt out across a harbor or bay entrance, or from a point of land.   The spit that exists near the entrance of Santa Barbara Harbor, shown below, is constantly dredged away to keep the harbor entrance open.

 

3. barrier island - a low-lying, elongate sandy island separating the open ocean from a shallow lagoon and mainland.   A barrier island can form where a vast amount of sediment is piled onto  a shallow continental shelf by small waves, or where coastal dunes became flooded due to a rise in ocean level since the last ice age approximately 19,000 years ago.   In the Southern California Bight, there were barrier islands where Los Angeles/Long Beach Harbor now exists.   The largest of the barrier islands was called Rattlesnake Island, shown below.   Part of Rattlesnake Island still exists, as Terminal Island.

4. delta - a large fan-shaped wedge of sediment formed where a sediment-laden stream enters the ocean.   Some large deltas, such as the Mississippi River delta, support vast wetland habitats as well as agriculture and mariculture.   Southern California deltas are transient features which tend to form and grow during times of prolonged rainfall, which triggers high-volume stream flow capable of transporting lots of sediment to the ocean.   Otherwise, moderate to occaisional heavy surf can wear away the deltas, such as the Malibu Creek delta shown below.

 

5. coastal plain - the relatively flat land adjacent to a shoreline.   Coastal plains usually form as streams spread sediment over a large floodplain area during a period of thousands of years.   The Los Angeles coastal plain is the largest in southern California, but there are many others like the Santa Barbara coastal cell shown below.

 

6. continental shelf - the generally flat and shallow ocean bottom extending from the shoreline out to the continental slope, where depth increases rapidly.   The shelf itself is mostly composed of terrigenous (land-derived) sediment deposited on the submerged edge of a continent, along with some biogenous skeletal sediment produced as marine organisms die in shelf water.   Note that shelves along tectonically active coasts tend to be narrow (<50 miles across) whereas shelves along passive coastal margins tend to be wider (>50 miles across).   On the topographic/bathymetric map below, the widest shelf is 16 miles across, and the narrowest is three miles across.   This map was produced by SCCOOS (Southern California Coastal Ocean Observing System).   The transition from the shelf edge down to the basin floor is referred to as the continental slope.

B. Erosional coastal features are formed by the combination of terrestrial processes (weathering, stream flow, and mass wasting) and marine processes (waves and currents).   Tectonic uplift can rejuvenate some of these features.

1. headland - a portion of an elevated coastal landscape that juts out into the ocean.   Formation of a headland can involve several processes, including erosion by streams, unequal weathering of coastal cliffs, wave action, and movement of rocks along a fault.   Some headlands are products of only one or two of these processes, whereas others are affected by all of the processes to varying degrees.   Point Dume, near Malibu, is a product of several of these headland-forming processes.

2. coastal cliff - forms where wave erosion over-steepens an elevated coastline.   This leads to mass wasting in the form of rock falls and slides, which cause the cliff to retreat from the ocean.   Homes built close to the edge of a coastal cliffs can be destroyed if this process occurs rapidly due to a major storm and large waves, combined with high tide which allows the waves to pound directly into the base of coastal cliffs.   The photographs below shows the remnants of a San Pedro, California neighborhood that was abandoned in the 1940's due to wave erosion and mass wasting of coastal cliffs.   For obvious reasons, the area is referred to by locals as "Sunken City".

How would you describe the state of equilibrium of the Sunken City coast line?   (Remember the terms steady-state, meta-stable and dynamic equilibrium?)   Is positive or negative feedback at work here?

3. wave-cut platform - fairly flat intertidal portion of a rocky shoreline at the base of coastal cliffs, formed by a combination of wave abrasion (energetic movement of sediment grains against rocks), wave force (pounding action and compression of air into rock fractures), and biological activity (boring organisms).   When exposed by low tide, platforms hold tide pools, an extreme environment requiring specialized survival adaptations by tide-pool organisms.   Portuguese Point and Inspiration Point, on Palos Verdes Peninsula, both have well-developed wave-cut platforms visible in the photograph below.

Note that uplifted platforms form wave-cut terraces, highly valued coastal landforms that offer flat terrain and beautiful vistas of the coastal environment.   Palos Verdes Peninsula, southern California has a total of 13 wave-cut platforms, representing progressive tectonic uplift over the past several million years.   The youngest, terrace 13, is closest to ocean level.

Below is a view of terraces 12 and 13, from terrace 11, Palos Verdes Peninsula.

 

4. submarine canyon - an incision cut into a continental shelf and slope.   Initially the erosion was by a stream flowing across a continental shelf exposed during a lowstand/regression of the ocean associated with past ice age/global-cooling events.   Later, global warming would lead to a highstand/transgression of the ocean, flooding the shelf and stream valley.   Coastal-ocean turbulence due to storm activity can mix sediment with water, forming a water mass denser than surrounding water.   Gravity pulls this dense water downward through the already-existing valley, forming turbidity currents capable of scouring the valley into a deep, long submarine canyon.   Worldwide there are over 100 submarine canyons along continental margins, with six just off the coast of southern California.   The multi-beam radar topographic/bathymetric map below shows the prominent features of coastal Los Angeles and vicinity.   Most obvious are the deep basins off shore, and the continental shelf.   The best-developed submarine canyon in this view is the Redondo Submarine Canyon (RSC), probably formed in conjunction with the Los Angeles River and past global-cooling events.

References

Garrison, T., 2007.   Oceanography: An Invitation to Marine Science, 6th Edition.   Thomson Brooks/Cole.   588pp.

Guilcher, A., 1958.   Coastal And Submarine Morphology, 2nd Edition.   Methuen &Co. Ltd.   274pp.

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Chapter 4

Classification of Coasts

 

Discussion

A single, all-encompassing classification scheme for coasts worldwide does not exist because of the variety of factors which shape and influence coastal zones.   Described below are three widely used approaches for coastal classification.

Tectonic Classification

This classification scheme relates coastal landforms and processes to the proximity of active tectonic boundaries to a coast; it works well for large-scale coastal classification.

A. active coastal margin      This type of coast is associated with the close proximity (usually less than 200 miles) of an active plate boundary to a coast.   Earthquakes and deformation of the crust are common.   The Andean style of subduction, where ocean crust is forced (subducted) beneath less-dense continental crust, is typically associated with an active margin.   Additionally, a transform boundary close to a coast can also have a significant impact on coastal processes and features.    The United States Geological Survey (USGS) map below shows the locations of Earth's plate boundaries.   Note the presence of boundaries close to the west coast of North America, but the absence of boundaries along the east coast of North America.

 

Active coastal-margin processes and features are listed below.

1. Crustal uplift forms coastal mountains, which drop sharply to the ocean.   Mass wasting from steep ocean cliffs and mountains contributes a wide range of sediment-grain sizes to local areas of the coastal ocean.

2. The continental shelf tends to be narrow, from less than a mile to 20 miles wide.   The narrowness of the shelf along convergent coastal margins is due in part to the steepness of the coastal margin, as well as the high-magnitude earthquakes common to such margins, which cause the outer edges of the shelf to break away and slide downward into deeper water.

3. Active coastal margins tend to be dominated by erosional processes, so they are usually rocky, with narrow, discontinuous beaches, small embayments, ocean cliffs, and headlands.

The photo below, from along the southern Oregon coast, shows classic features of an active coastal margin, with a steep mountainous slope, rocky cliffs and embayments, and a small beach.

 

The narrow continental shelves along the coast of southern California, shown in the Southern California Coastal Ocean Observation System (SCCOOS) map below, suggest that our coastal margin is active.   How else do we know that we live along an active margin?

 

B. passive coastal margin      In this context, "passive" refers to a general absence of earthquake and crustal-deformation activity.   In this situation, the nearest active plate boundary is more than 200 miles off shore due to a long-lived divergent plate boundary that has caused a continental margin to drift far from the original rift zone.   Peruse the USGS map below.   Which ocean is surrounded by passive coastal margins?  

 

Passive coastal-margin features are listed below.

1. The absence of stress within the crust along a passive coastal margin allows broad, flat coastal plains to develop, with few elevated topographic features.

2. The continental shelf tends to be very wide, often from 50 to 100 miles across.   This is due in part to the the long-term erosion of inland features and the resulting deposition of detritus (clay, silt, sand, gravel and organic matter) into the shallow coastal ocean.   In addition, the absence of high-magnitude earthquakes enables sediment to settle and remain along shelf edges, allowing the shelf to grow in width over time.

3. Passive coastal margins are dominated by depositional processes from streams and coastal currents, so they are characterized by extensive beaches, long spits and barrier islands, as well as large embayments that reach far inland.

The space photograph below, taken in 1985, shows part of the Gulf coast of Texas, a classic example of a passive continental margin.

Sediment-Budget Classification

This classification approach relates coastal landforms to either erosional or depositional processes, whichever dominate along a particular shoreline.   The basic idea is that an important aspect of a coastal system is that there is either a net loss or a surplus of sediment within the system - hence the "sediment-budget" name for this coastal classification scheme.   Note that seasonal variations in stream flow/delivery of sediment into a coastal system can temporarily alter the system from the erosional to depositional regime, or vice versa.   Overall, this approach works well for localized coastal classification, whereas the tectonic classification described above is a big-picture, generalized approach to coastal classification.

A. erosional coast      Along this type of coast, wave and current activity is vigorous, removing more sediment than is deposited.   Characteristic features include coastal cliffs, wavecut platforms and terraces, headlands and stacks.   Forces of weathering and erosion will gradually subdue these features, but they can be rejuvenated by episodes of tectonic uplift.   Much of the western North American coast is considered to be erosional in nature, although some stretches have landforms characteristic of depositional coasts.

B. depositional coast      Where depositional features dominate coastal landforms, wave and current activity tends to be moderate, with streams dumping more sediment into coastal-zone water than is removed by erosional processes.   Characteristic features are broad and long beaches, spits, barrier islands, and a general absence of erosional features.   Tectonic uplift is not a factor, but down-dropping (subsidence) could be.   Much of the eastern and Gulf coasts of North America are depositional coasts.

Note that along some erosional coasts, like those of San Diego County, there are local areas of subsidence with depositional features such as the estuaries and wetland tidal flats shown below.

Dominant-Process Classification

This scheme is based on the predominant natural activity in a coastal zone, and there is a lot of overlap with the sediment-budget classification described above.   Explanations of the physical aspects involved in each of the subdivisions of the dominant-process classification of coasts are provided to enhance your understanding of coastal-system science.

A. Wave-dominated Coastal Systems      This subdivision includes most of the world's coasts, where wave activity is the main agent of coastal erosion and deposition, providing energy for near-shore currents and sediment distribution.

1. wind waves      Waves that you see on the ocean surface are actually wave-form energy traveling through the surface ocean.   This energy was transferred into the ocean by wind flowing over the ocean surface, with friction between the two fluids (air and water) converting the wind energy into wave-form energy.   Note that the depth at which waves interact with the ocean floor (oceanographic term is they "feel bottom") is roughly half the wave's length.   So, waves of great wave length will feel bottom in deeper water than waves of shorter wave length.

a. Wind-generated waves travel nearly friction-free across the ocean, so they can cover thousands of miles from where they were formed by a storm to where they finally break and release their energy into the coastal zone.   The diagram below, from the Office of Naval Research, illustrates the main components of an ocean wave.

 

 

b. Wind waves formed at a storm center will be chaotic, traveling in all directions, with different wave lengths, heights, and velocities.   With time and distance from the area of origin, waves become sorted out according to size and length, forming uniform waves on the ocean surface called swell.

c. Local coastal wind can form waves that become superimposed upon swell.   Typically, this forms a choppy ocean surface not ideal for surfing.   Since coastal winds tend to increase in velocity during the afternoon, the best surfing is usually during the early morning.   Below is coastal Long Beach on a breezy day.   Note the white caps and wind chop kicked up by the breeze.

 

d. As waves approach a coast, their wave bases begin to feel bottom, slowing their velocity and altering their shape, as shown below.   (Note that the depth of a wave's base is a function of its wave length; wave base = 1/2 wave length. Most wind waves have lengths from 100 to 300 feet, so they begin to feel bottom in shallow depths of 50 to 150 feet, eventually breaking at a depth of 1/20 wave length, or 5 to 15 feet from our example above.) 

 

As a wave breaks, it can release tremendous energy into the surf zone forming longshore and rip currents.   Or, a wave can break directly against a rocky shoreline, exploding rocks apart or hurling sediment grains against rocks, causing abrasion and formation of erosional coastal features.   Note that the larger the wave, the more energetic are the resulting processes.

e. Generally, the type of breaking wave along a shoreline is controlled by the shore's gradient.

(1) plunging breaker   A higher-gradient shore produces steep-fronted waves that release energy suddenly as the wave crest curls and drops over the wave front.   For surfers, this is where the action is.

 

(2) spilling breaker    A low-gradient shore causes a wave to break continuously as it travels shoreward, so the wave crest cascades down the wave front.   Spilling breakers do not have steep faces or rapid release of energy, so they tend to make for poor surfing, as shown in the photograph below.   

 

Spilling waves can form as a secondary wave resulting from the breaking of large waves some distance off shore.   These lesser waves travel over a shallow and nearly flat ocean bottom, with poorly developed wave crests that tend to spill as the wave surges ashore.   Note the secondary, spilling breaker approaching the Palos Verdes shoreline on the left side of the photo below, with plunging breakers further off shore.

 

f. Most coasts experience wind waves.   Exceptions are protected harbors, bays and estuaries, and ice-protected coasts at high latitudes.   Mid-latitude coasts in line with storm tracks tend to experience the largest wind waves.

 

2. tsunami      A few times a year Earth's oceans will experience a sudden and large-scale displacement of water.   Immediately after the displacement has occurred, gravity attempts to return the ocean to a state of equilibrium, propagating a fast-moving ocean wave outward from the disturbed area - a tsunami.   However a tsunami is generated, it travels with great speed through the ocean, with initial speed approaching 500 miles per hour.   Tsunami have very long wavelengths, so they are always in contact with the ocean floor.   This causes them to gradually slow in velocity as they travel across the ocean.   As a tsunami moves over a continental shelf, it slows dramatically causing wave height to abruptly rise from one or two feet to 10 to 30 feet in height.   Tsunami can surge far inland causing great destruction in a coastal zone.   This is referred to as "runup".   Once the surge loses momentum, gravity will draw the water back into the ocean, called "backwash".   This can be as dangerous as the initial surge runup.   The diagram below, from the New Zealand government's Environment Waikato web site, illustrates the physical changes that occur to a tsunami as it moves into shallow water.   A misleading aspect of the diagram is the shortness of the wave length of tsunami.   In reality, tsunami wave length can be 125 miles, so a tsunami wave crest can be 40 to 60 miles long!   Why is this significant?

 

Described below are the two most common ways to form tsunami.  

a. Most tsunami form due to the sudden vertical movement of the ocean floor along a fault in the ocean crust.   The vertical movement of the crust displaces the ocean above it, producing a tsunami.   This movement also releases energy into the crust, generating an earthquake.   Note the the earthquake is coincident with the tsunami, it does NOT produce the tsunami.   A recent example of this type of wave was the Indonesian tsunami event of December, 2004.   The photos below, of the tsunami washing ashore at Phi Phi Island, were taken by J.T. and Caroline Malatesta.

  

The tsunami surges ashore.

 

                          

                 The tsunami washes over low-lying area.

 

b. Less common are tsunami formed in association with a mass-wasting event, often triggered by an earthquake, which displaces a large volume of ocean water.  Two possibilities are given below.

 (1) As a submarine slide draws down the overlying ocean, a depression forms in the ocean surface.   Water immediately fills in the depression, sending a wave trough and crest moving outward in all directions.   This happened off the coast of Papua New Guinea in 1998, resulting in the deaths of more than 3,000 people.   Below is a USGS recreation of the event, as well as a link to a video clip.

 

Link to USGS Medium Resolution Movie of New Guinea tsunami, 431x301 pixels

(2) The fjords of southeastern Alaska, a tectonically active region, are prone to massive slides from the coastal mountains.   As a slide rumbles into a fjord, it displaces the water ahead of it forming a rushing wall of water that no boat can out run.   Lituya Bay, Alaska pictured below has a history of such events.   In 1958, a huge slide formed a tsunami that moved out from the Bay, over the spit, and dispersed its energy into the Pacific Ocean.   In the USGS photo below, note the barren slopes along the Bay shore that were deforested by this powerful event.

 

 

c. Tsunami are profoundly influenced by refraction because they are constantly in touch with the ocean floor, so they can cause destruction on the lee side of an island thought to be protected from a tsunami.   This occurred in Sri Lanka during the 2004 Indonesian tsunami event.  Below is the address to an excellent Quicktime movie showing the path and refraction of the 2004 tsunami.

http://www.ngdc.noaa.gov/seg/hazard/img/pmelTITOV-INDO2004.mov

 

Some oceanographers think that wind waves have a greater influence on coastal systems than the rare tsunami, but other marine scientists and geologists argue that tsunami have a greater impact on coastal systems.   Who is correct?

 

B. Tide-dominated Coastal Systems      These coastal zones are strongly influenced by the daily rise and fall of the ocean surface, and the resulting flood and ebb tidal currents.   Tidally dominated coastal systems tend to be low-gradient shorelines, often where low-lying river valleys transition into estuaries (mix of fresh and salt water) along a  coast.

1. Tide-dominated coasts are rare, comprising 1% of the world's coastal zone.   But, they are significant because:

a. they provide critical habitat to migratory fowl that feed and nest in wetlands, and to juvenile fish and crustaceans that hatch and feed in tidal channels and mud banks of wetlands.

b. they have long been areas of human habitation going back 1000's of years in history, providing rich hunting and fishing grounds for indigenous peoples.

and

c. they include the world's bays, natural harbors and estuaries which are generally well-protected from wave activity.

Some examples of coastal regions dominated by tidal action and protected from waves are San Francisco Bay, the Thames River estuary (England), and Newport Bay (Orange County).

 

2. Significant processes along tide-dominated coasts include:

a. current flow stimulated by the rising and lowering tide.   Tidal currents distribute sediment and disperse larvae within an estuary, and can extend the reach of salt water far into an embayment.   Also, tidal currents can help remove pollutants that might otherwise accrue to toxic levels in an estuary.

b. alternating wetting and drying of marshes and tidal flats, which is essential to the varied organisms adapted to the intertidal environment.

and

c. occasional flood events which can radically alter tidal channels and flats, bury marsh grass and infauna under a layer of mud, and disperse juvenile fish and crustaceans into the open ocean.   A major flood may reconfigure shoreline bars, spits, and beaches, permanently altering backbay circulation.  

The changing flow locations of the Santa Ana River are included below on the map of southern California, produced by City Maps 2005.   Prior to 15,000 years ago, the Santa Ana River (SAR) flowed southward over the Los Angeles coastal plain, cutting across coastal bluffs and carving Newport Bay.   About 15,000 years ago the river abandoned its course through Newport Bay, flowing into the Pacific Ocean at what is now Alamitos Bay, Long Beach.   The SAR continued with this path until 1825, when it shifted course during a major flood event.   Then, it connected to the Pacific Ocean at what is now Costa Mesa, forming a spit and significant coastal wetlands in the process.   The sediment introduced by the SAR presented a problem to Newport Harbor developers, who lobbied state and federal officials to redirect the river elsewhere.   This was accomplished in 1920 to the detriment of the wetlands that had formed during the prior 95 years in lower Newport Bay.   

 

The aerial photographs below show the present state of the Santa Ana River, confined within concrete banks (photograph 1), and where it flows into the Pacific Ocean (photograph 2).   Both photographs can be found on the Orange County Region web page of the web site Aerial Photography of Southern California.

 

3. Tidal Forces and Currents

a. Tidal Forces

(1) As discussed in Chapter 1 Introduction to Coastal Systems, Earth's tides are produced by the interplay of gravity within the Earth-Sun-Moon system, which causes the ocean to bulge upward toward the Sun and Moon.

(2) The orbital motions of Earth around the Sun, and the Moon around Earth, generate inertia exactly counter to the tidal gravity effects of the Sun and Moon on Earth.   The diagram below illustrates the changing tidal conditions due to the locations of the Sun and Moon relative to Earth.

 

(3) Spring tides form when the the Earth-Sun-Moon system is aligned, generating the highest high tides, and the lowest low tides.   A coast will experience its greatest tidal range during a spring-tide event.   Along coastal southern California, the spring-tide range is usually around seven feet from low to high tide.   The best time to visit a tidepool is during the low-tide component of a spring tide event, when the lowest intertidal zone is exposed.   Below is a photograph of tidepools along Palos Verdes Peninsula, exposed during a spring-tide event.

 

(4) Neap tides form when the Earth-Sun-Moon system is not aligned.   More specifically, this occurs when the Sun and Moon form a right angle with Earth.   In this orientation, tidal forces are spread fairly evenly over Earth's surface resulting in high tides that are not very high, and low tides that are not very low.   Along coastal southern California, the neap tide range is from two to three feet.

 

b. Tidal Currents form due to the rising and falling of the tides.   This happens twice daily along the coast of California, which has a "mixed" tidal pattern, with two unequal high tides and two unequal low tides per day.   (Much of the eastern and Gulf coasts of North America have simpler tidal pattern, with only one high tide and one low tide per day.)

(1) A flood current forms as the tide rises, forcing ocean water inland through tidal channels.   During a spring tide event, flood-current velocity can be high, forming small eddy currents and making navigation in tidal channels more challenging.   Where the range between high and low tide is greater than 15 feet, flood currents can form a tidal bore, a wave representing the leading edge of the rising tide.   The first two photos below are of the Severn River tidal bore, in England, taken by Donny Wright.   The longest surf ride on the Severn bore is 7.6 miles up river!   The third photo, also of the Severn River, show the force with which it can travel up river, eroding the shoreline as it goes (photo by David Burges)

The map below is a product of a joint program between the USGS and NOAA called the San Francisco Oceanographic Real-Time System (SFPORTS).   These maps are updated daily to inform local ship captains and sailors about tidal currents and other physical attributes of the Bay area environment.   This map illustrates the tidal current generated by a rising tide - a flood current.   Where the current squeezes through the Golden Gate, flow velocity can exceed seven miles per hour.

 

(2) An ebb current forms as the tide lowers, draining water from inland bays and estuaries.   As with flood currents, ebb currents can be dangerous during spring-tide events, especially where tidal range is great.   Below is a SFPORTS map illustrating tidal-current flow on the same day as the map above, but seven hours later.   Note how the ebb current is squeezed as it passes through the Golden Gate.   (These maps were copied from an excellent web site by Karen Grove of San Francisco State University.)

 

(3) Along the California coast, tidal currents cease flowing twice a day.   This condition, called slack tide, exists temporarily as flood current transitions to ebb current with the falling tide, or vice versa.    When would slack tide have occurred on the date represented by the maps above?

 

4. Controls on a Coast's Tide Range

a. A tide-wave crest follows a circular path around an ocean basin.

(1) The tides are actually forced waves, that is they are constantly being dragged along by gravity/inertia of Sun-Earth-Moon system interactions.

(2) A tide wave consists of a crest (high tide) and a trough (low tide), with a wave length 1/2 the circumference of Earth.

(3) As the tide-wave crest is dragged along, there is some movement of ocean water molecules.   Therefore, the Coriolis effect steers the wave crest to the right in the northern hemisphere.   As the wave crest is pulled along by gravity/inertia, it interacts with the continents, circling around an ocean basin in a counter clockwise direction about a central point (amphidromic point) within the ocean basin.   At the amphidromic point, there is no discernible tide, but the farther away from this point, the greater the tidal range.  

On the map below, from Garrison 2007, note the amphidromic point closest to southern California.   It is the main control on our tidal pattern, with the other amphidromic point further south adding complexity to our tides along the west coast.   The numbered lines represent the tide-wave crest as it interacts with the west coast of North America over an 11 hour period.

 

(4) So, coasts far away from an ocean basin's amphidromic point tend to have the greatest range from low to high tide.   Based on this statement and the map above, should California's coast experience a greater tide range, or should the Alaskan coast?

 

b. The shape of the coastal-ocean floor, its bathymetry, can cause the tide wave to refract and become focused on a particular stretch of shoreline.   This is a localized effect, impacting only a few miles of a coast.

c. A broad continental shelf can slow a tide wave, compressing it and increasing the tidal range along a coast.

d. Funnel-shaped embayments, gulfs, and estuaries tend to rapidly compress a tide wave as it travels inland.   The rapid shallowing and narrowing effect can radically slow the tide wave, increasing it height dramatically.   The Encarta map below shows the funnel shape of the Cook Inlet, where it extends inland to Anchorage, Alaska (see the yellow dot on the map above).

 

e. A combination of two or more of the possibilities listed above can form tide-range extremes greater then 30 feet!

 

5. Coastal Tidal Influence and Significance

a. Tidal influence along a shoreline is related to the overall tidal range experienced along the coast, and the land gradient from the shoreline inland.   A coast with a low gradient and high tidal range, such as the north end of the Gulf of California, will experience several miles of inundation during the swing from low to high tide, especially during a spring tide.

b. Such far-reaching tidal influence along a very broad beach promotes algae growth within sand pore spaces, attracting infaunal invertebrates, which in turn attract a variety of shore birds, forming a rich coastal ecosystem.

c. The upper few inches of sediment along broad beaches tends to dry out due to long exposure to the Sun, making the beach surface susceptible to wind erosion, but leading to the the formation of dunes on the back beach.   Once stabilized by plants, such dunes can form a diverse ecosystem of their own.

d. Tidal influence can reach many miles inland along estuary and wetland channels, enabling salt-water species to live far from the ocean, salt weathering to proceed along cliffs and exposed rocks, and flocculation of suspended clay minerals to occur as they react with salt ions in the water.

e. Note that tidal environments worldwide, including tidepools, wetlands, estuaries, bays, and beaches, are under pressure from human activities due to urban sprawl, pollution, and industry.

The aerial photograph above shows the low-gradient coastal zone of Long Beach and Seal Beach.   Tidal circulation is critical for the health of Alamitos Bay, and tidal influence reaches far inland up the San Gabriel River channel.

 

Tidal Patterns for Western North America

Complete the tide exercise (click here), and refer to the map of southern Alaska to answer the questions.  

 

C. River-dominated Coastal Systems      This type of coast exists where a delta is prograding into the ocean.   A delta is a large wedge of sediment that forms as a river/stream diffuses into a standing body of water, loses its energy, and deposits its load into the ocean.   In a very real sense, the high volume of river flow and its sediment load overwhelm the local coastal ocean where river and ocean meet.

1. Formation of a delta requires:

a. a vast amount of sediment derived from inland mountains, and a river to deliver the sediment to a coastal zone.

and

b. a shelf or submarine fan on top of which the delta can form and grow.      

 

2. Delta classification is according to two schemes:

a. morphology (shape) when viewed from above.   Common delta shapes include:

(1) fan-shaped - prograding delta front is somewhat modified by wave and current activity; distributary channels carry sediment to the delta front, maintaining the fan shape.   The Nile River delta is fan-shaped.

 

(2) birds-foot delta - prograding delta lobes are little affected by waves.   The river forms natural levees as it floods, forming long distributary channels that carry sediment to outer portions of the delta.   The delta front is highly irregular.   The Mississippi River delta is and example of a birds-foot delta.   Below is a Seasat synthetic-aperture radar image of the active portion of the Mississippi River delta, showing the classic birds-foot shape.

 

(3) cuspate delta - the delta front is greatly modified by wave erosion and current activity, with little actual progradation of the delta above water - most oceanward growth occurs underwater.   The Rhone River delta (France) is a cuspate delta.   This public-domain map from Wikipedia shows the Rhone delta front, with large spits formed by the combination of wave and longshore-current activity.

 

(4) estuarine delta - the delta occupies a drowned/submerged river valley that has become infilled by sediment.   The delta shape is defined by the valley.   Examples of estuarine river deltas are the Sacramento River delta (space photograph), or the Greenland delta shown in the second photograph below.   (Photo by Niels Nielsen.)

 

b. dominant process affecting delta

(1) river-dominated deltas - extend outward into the ocean as a river delivers abundant sediment, with little wave activity to wear down the delta front.   This is equivalent to a birds-foot delta, shown in the Seasat radar image of the Mississippi River delta below.

 

(2) tide-dominated deltas - have a wide delta front crossed by numerous channels which transport river and tidal-current flow.   Channels tend to be shallow and easily clogged with sediment, and the delta front is fingerlike.   This is equivalent to an estuarine delta such as the Sacramento River delta and the Ganges-Brahmaputra delta in the Bay of Bengal (shown in space photograph below).

 

(3) wave-dominated delta - wave action redistributes river-deposited sediment forming a relatively smooth delta front.   This is equivalent to cuspate/fan-shaped deltas such as the Rhone and Nile deltas.   The space photograph below shows the typical delta front formed by wave action.

 

3. Significance of Deltas

a. Deltas have traditionally been sites of human settlement due to the abundance of freshwater, fertile soil for agriculture, and ready access to the coastal ocean via river/tidal channels.

b. Floods deliver sand, silt, and clay, and well as lots of organic matter (mainly plant detritus) to a delta.   This combination of sediment forms rich farm land where it settles onto a delta plain as a flood event begins to wane.   As more sediment is deposited on top of a growing delta, deeper layers compact and heat up, converting organic matter into hydrocarbons - oil and natural gas.

 

4. Hazards of Living on a Delta

a. Since deltas are low-lying areas, they are prone to flooding, which is good for the soil, but hard on human settlements.

b. Powerful storms such as hurricanes/cyclones moving from the ocean onto land form large wind waves and also draw up the ocean surface below them, since they are intense low-atmospheric pressure centers.   As a hurricane/cyclone moves ashore, it pushes a wall of water up to 25 feet high ahead of it - a storm surge.  

The NOAA diagram below illustrates the flooding caused by the surge.   Note that large wind waves are superimposed on the surge.   This combination of surge and wind waves is both deadly and destructive.

 

Hurricane Katrina, above, struck the Gulf coast of North America in 2005.   Atmospheric updraft and associated rising of ocean level is greatest at the eye of the storm.   The surge advances ahead of the eye of the storm, increasing in height until the eye passes inland.   Depending on the coastal location, Katrina's storm surge ranged from a few feet up to 25 feet.

The photograph above, taken by Don McClosky, shows the surge overflowing a levee.   Water level in New Orleans rose at a rate of one foot per ten minutes thereafter.   Note the 15 to 18 foot wind waves on the surge surface!   Below, boats became stranded far inland as the surge receded from the Gulf coast.

 

c. The combination of flooding from heavy rainfall and storm surge often coincide with each other, devastating coastal communities.   The nation Bangladesh occupies the Ganges-Brahmaputra delta.   This low-lying nation and its millions of poor people have a history of cyclonic disasters - the cyclone of 1970 killed some 300,000 people, and the cyclone of 1991 killed roughly 140,000 people!   By comparison, Hurricane Katrina was responsible for the deaths of less than 2,000 people in the United States.   The photograph below, taken by USAF Staff Sergeant Val Gempis, shows some of the aftermath of the 1991 Bangladesh cyclone.

Exercise

Inspect the photo below, which shows a small stretch of coastal southern California.   Evaluate the significant processes at work here, then use the dominant-process classification scheme to determine if this coast is wave, tide, or river-dominated, or some combination of these options?  

References

Garrison, T., 2007.   Oceanography: An Invitation to Marine Science, 6th Edition.   Thomson Brooks/Cole.   588pp.

Haslett, S.K., 2000.   Coastal Systems.   Routledge, London and New York.   218pp.

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Chapter 5

   

California Continental Borderland

Discussion

California’s Continental Borderland and the Southern California Bight refer to the same geographical area of coastal California and the Pacific Ocean.   The Southern California Bight, which will be covered in Chapter 6, is the curved indentation of the west coast of North America south of Point Conception down to the Mexico border.   The Bight includes the Pacific Ocean out to the Patton Escarpment roughly 100 miles offshore of southern California.  

The California Continental Borderland represents a unique tectonic region that formed along with the San Andreas Fault during the past 27 million years. Specifically, the Borderland is the unusual and active ocean floor offshore of southern California.   So, Southern California Bight is an oceanographic term, and California Continental Borderland is a geologic term.   To understand the origin of the Borderland, you must have a working knowledge of plate tectonics theory, which is provided below.

Plate Boundaries

There are three basic types of plate boundaries, formed as the edges of lithospheric plates move relative to each other.   Plate movements are due to convection of the asthenosphere (beneath the lithosphere), and gravity, which pull elevated portions of plates downward.   Below are brief descriptions of each type of boundary.

1. divergent boundary - plates move away from each other, forming a rift valley where new crust is created due to volcanic activity along with ridges that run parallel to the rift valley.   Ridges are uplifted due to the high heat flow beneath a divergent boundary, as illustrated by the diagram below, from the plate tectonics web site by the Moorland School, United Kingdom..

2. transform boundary - plates move horizontally past each other transferring stress into the surrounding crust, with lots of earthquakes but little to no volcanic activity occurring.   In general, transform boundaries exist to connect one divergent boundary to another divergent boundary.   This is illustrated in the diagram below, by Dr. Bruce Railsback, University of Georgia.

3. convergent boundaries - plates move toward each other, producing uplift of the crust, tall mountains and very high-magnitude earthquakes.   Subduction boundaries form where ocean crust is forced beneath another plate, and collision boundaries form where two continental plates collide with each other.   Both diagrams are from the Plate Tectonics web site of Moorland School, United Kingdom.

           

Origin of the California Continental Borderland

The California Continental Borderland has developed in association with the San Andreas Fault, and it is still being shaped due to movement along this transform plate boundary between the Pacific and North American plates.   Although the San Andreas Fault is 50 to 100 miles inland from the coast line, it exerts a profound influence on southern California’s continental margin, making it very active and unique from anywhere else on Earth.   The diagram below illustrates the relationship of the Pacific and North American plates, and the plate-tectonics role the San Andreas Fault plays by connecting the East Pacific Rise to the Juan de Fuca Ridge.   (from Irwin, 1990)

The following is a brief history of the development of the California Continental Borderland based largely on the work of Tanya Atwater, UC Santa Barbara.   A link to one of her Quicktime animations showing the evolution of tectonic activity in the eastern Pacific Ocean basin is below.

http://emvc.geol.ucsb.edu/animations/quicktime/lg01PacN.mov

1. Around 120 million years ago, subduction was occurring along the coast of much of California, with powerful earthquakes and explosive volcanic activity common.   A modern analogy would be coastal Oregon and Washington today, with subduction occurring offshore in the Cascadia trench, volcanism in the Cascade volcanoes, and the occasional powerful earthquake.   Here, continental shelves are narrow due to steep shorelines and earthquake activity.   

2. Subduction activity along the coast of southern California started diminishing approximately 27 million years ago when the East Pacific Rise began subducting beneath the central coast of California.   At this point, transform motion developed to connect the separated components of the East Pacific Rise still existing to the north and to the south.   The proto-San Andreas Fault formed about 18 million years ago, as a series of offset faults west of the present San Andreas Fault.   The plate boundary was flexed outward, away from the continent.   Shearing along strands of the proto-San Andreas Fault was accompanied by extension of the ocean crust, forming faults that would later determine major features of the California Continental Borderland.   Roughly 17 million years ago, a large block of crust began rotating clockwise as the Pacific Plate continued to move toward the northwest past the North American Plate.   Other smaller crustal blocks rotated, subsided, and/or uplifted until about 4 million years ago, when the San Andreas Fault formed in its present location.

3. The San Andreas Fault now connects the East Pacific Rise in the northern corner of the Gulf of California to the Juan de Fuca Ridge and Cascadia subduction zone off the northern California coast.   Stress due to the grinding of the Pacific and North American plates past each other is transferred to offshore faults of the Borderland, making it tectonically active today.  

Description of the California Continental Borderland

The California Continental Borderland refers to the ocean floor and offshore islands from the southern-California shoreline out to the Patton Escarpment.   Beyond the Escarpment, the ocean floor is more typical of a deep ocean basin, with a relatively flat ocean bottom and a few seamounts.   

1. The Borderland is characterized by a series of generally northwest-trending ridges, banks, islands, and basins.   The ridges are not divergent plate boundaries such as the Mid-Atlantic Ridge and the East Pacific Rise.   Instead, they are products of compression and uplift along faults or folds in the crust.   Similarly, banks are elevated linear areas such as the Pilgrim Banks, or locations of underwater mountains (seamounts) that are just below present ocean level.   Cortez Bank is an example of this type of bank.   The southern Channel Islands (San Nicolas, Santa Catalina, and San Clemente islands) are elongate, with their long edges oriented toward the northwest.   

2. Seismic profiling of the ocean floor and underlying sediment and rock indicates that active faults are present along at least one side of each island, with folded rock and sediment and lesser faults present along other sides of islands.   Similarly, the isolated basins of the Borderland are bounded by active faults and zones of intensely folded and crumpled sediment and rock.   View a Powerpoint presentation, given by Dr. Robert Francis, which addresses active faults and other structures within the Inner Borderland area adjacent to Los Angeles and Long Beach harbors, Long Beach and Orange County.  

The diagrams below indicate that the California Continental Borderland is a seismically active region, with each dot representing an earthquake epicenter.

 

3. The generally northwest trend of the basins, ridges, banks and islands of the Borderland is roughly parallel to the orientation of the San Andreas Fault, suggesting that their formation and evolution are directly related to movement along the transform plate boundary.   This is apparent on the modified Monterey Bay Aquarium Research Institute map below.  

4. Sedimentation in the California Continental Borderland is a combination of terrigenous and biogenous processes.

a. Basins of the Borderland range in depth from 3,000 to 6,000 feet in depth.   They receive terrigenous and biogenous sediment in several ways.   

(1) Finer-grained terrigenous sediment (clay and silt) is carried out over the Bight/Borderland by offshore winds, or introduced into the coastal ocean by rivers during and after rain events.   Surface ocean currents can disperse these tiny particles throughout the Bight/Borderland.   Gravity pulls the tiny grains to the ocean floor over a period of weeks to months.

(2) Coarser-grained terrigenous sediment (sand and gravel) is carried into basins by turbidity currents descending through submarine canyons from shallow, nearshore water out onto the basin floor.   (Turbidity currents form when a major storm or an earthquake disturb shelf sediment, mixing it with water.   This mixture is denser than the surrounding water, so gravity pulls it down slope to greater depth.)   Typically, the sand and gravel form a submarine fan on the periphery of a basin.  

(3) Landslides from steep coastal cliffs and slopes can also send coarse sediment into basins where the shelf is narrow, such as along Palos Verdes Peninsula on the mainland coast, or along many of the Channel Islands' coasts.   Local rip currents can transport the sand, gravel and cobbles to the nearby shelf edge where they cascade downward to the edges of the basins.   The northwestern end of Catalina Island, shown below, has steep cliffs that drop off to a very narrow shelf, and then into the Catalina Basin.

 

(4) Larger biogenous sediment typically originates from nearshore coastal water, and is carried into the basins, along with sand and gravel, by turbidity currents.   It is usually mixed with terrigenous sediment on submarine fans.   Carcasses of whales that die as they swim across the Southern California Bight can settle on the deep basin floors, randomly contributing their large skeletons to the basin sediment.   (These carcasses, until picked clean by scavengers, can form isolated and unique ecological zones on an otherwise barren basin floor.)

(5) Smaller biogenous sediment is usually in the form of fecal pellets excreted by swimming (nektonic) marine animals.   The tiniest, clay-sized pellets originate from filter-feeding zooplankton.   Such fecal pellets are very abundant on the deep-basin floors.

The diagram below shows the Borderland basins.   The large basins further from the mainland California coast contain very different sediment than the Santa Monica and San Pedro basins.   Explain why this would be the case, and compare and contrast the sediment that exists within the smaller nearshore basins to the larger offshore basins.

 

b. The shallow ocean floor of the Borderland, the continental shelf and narrow island shelves, receives a wide range of terrigenous and biogenous sediment.

(1) Along the mainland coast of California, the primary sediment is sand weathered and eroded from inland mountains and coastal cliffs.   This terrigenous sediment is transported by longshore currents, helping to form the beautiful beaches that southern California is famous for.   Rip currents can carry this sediment offshore, but eventually it is returned to the beach by small waves.   With time, most beach sediment's fate is to descend into a submarine canyon and then out onto basin floors.   At every beach there is a small biogenous sediment component, mainly fragmented shells of molluscs.

(2) Borderland islands receive little rainfall, and their overall surface areas are small in comparison to the mainland, so little terrigenous sediment is carried into the coastal zones of the islands.   So, their beaches tend to be short and narrow, with a larger component of biogenous sediment than beaches of the mainland.   This condition extends into the nearshore coastal-ocean floor as well.

c. Ridges and banks of the California Continental Borderland are separated from islands and the mainland by numerous basins which trap most terrigenous sediment.   Therefore, ridges and banks are covered primarily by biogenous sediment of all sizes and shapes.

 

Effects of the Continental Borderland on Coastal Southern California

The varied topographic features of the Continental Borderland have a significant effect on waves and currents offshore of southern California.

1. Borderland features influence currents in the Southern California Bight, especially with regard to eddy currents, which mix water from the surface down to the ocean floor on the bottom of Borderland basins.

2. Borderland islands impact  wind waves by absorbing waves that directly strike the islands, forming a wave shadow behind the islands.   The islands also diffract wind waves, causing destructive interference of interacting swell and reducing energy and height of swell that eventually breaks along the coast of southern California.   Note the significant decrease in wave height behind the Channel Islands on the Scripps wave map below.

 

3. Since the Continental Borderland is seismically active, the potential for tsunami generation here is very real.

a. Several active faults, including the Palos Verdes and Cabrillo faults, cut across the San Pedro Bay shelf just off shore of Long Beach.   Seismic profiles indicate that there is an element of vertical movement along theses faults, which could potentially produce a tsunami should a long stretch of either fault rupture with significant vertical movement (up or down).

Below is a United States Geological Survey image derived from multi-beam sonar data.   The locations of the Palos Verdes and Cabrillo faults are shown, based on work by Dr. Robert Francis (CSU Long Beach Department of Geological Sciences).

Below is a seismic profile of the Palos Verdes Fault (vertical discontinuity near middle of profile), clearly showing the west (left) side of the fault uplifted about 12 feet higher than the east (right) side of the fault.

Since the Palos Verdes Fault is so close to shore, there would be little if any warning time for coastal inhabitants in case a tsunami was generated due to movement along this oblique-slip fault.

b. Tectonic activity within the Borderland can produce earthquakes that might, in turn, generate mass wasting along the steep island coasts and adjacent ocean floor.   This could result in the formation of tsunami aimed directly at coastal southern California.   The most significant local tsunami threat for the Long Beach and Orange County coast is from Santa Catalina Island.   A powerful earthquake on the island could produce a sizeable slide from the east-facing island slopes, or trigger an underwater slide from the narrow continental shelf.   Either prospect could send a destructive tsunami racing 25 miles across the San Pedro Channel, with little time to warn and evacuate coastal residents and recreationists.  

The USGS diagrams below provide a three-dimensional perspective of the Borderland near Long Beach and Catalina Island.   Note the narrow continental shelves that drop off steeply into the San Pedro Basin.

 

 

Below is a photograph of the northeastern side of Catalina Island, which faces the southern-California mainland.   Note the steep slopes with the potential for large-scale mass wasting.   If a tsunami originated from this coast, and traveled at an average speed of 450 miles per hour, how long would it take to strike the Long Beach coast?   (Determine distance from first diagram above, then use the equation time = distance/rate.)

 

Below is a three-dimensional multi-beam sonar image, from Normark, et al., 2004, that clearly shows the deposit from a major submarine slide and debris flow that occurred 7,500 years ago along the continental slope off the Palos Verdes Peninsula coast.   Based on the size of the deposit and how far it traveled across the ocean floor, it is estimated that it may have caused a tsunami whose original wave height was from 25 to 160 feet high.   If a similar tsunami occurred today from the same location, would Long Beach be affected?   (Hint: review the Papua New Guinea tsunami event.)

Conclusion

The California Continental Borderland's history is a tale of complex plate-tectonics activity and long-term sedimentation.   The product of these processes is one of the most unusual and tectonically active ocean-floor regions on the planet.   The features of the Borderland affect ocean waves and current circulation, and add tremendous variety to the coastal ecosystems of southern California.

References

Atwater, T., 1998, Plate Tectonic History of Southern California with emphasis on the Western Transverse Ranges and Santa Rosa Island, in Weigand, P.W., ed., Contributions to the Geology of the Northern Channel Islands, Southern California: American Association of Petroleum Geologists, Pacific Section, MP 45, p. 1-8.

Berelson, W.M., 1991, The Flushing of Two Deep-Sea Basins, Southern California Borderland, Limnol.Oceanogr., 36(6), 1150-1166.

Fisher, M.A., Normark, W.R., Langenheim, V.E., Calvert, A.J., and Sliter, R., 2004, Marine Geology and Earthquake Hazards of the San Pedro Shelf, Southern California, U.S. Geological Survey Professional Paper 1687.

Francis, R.D., 2009, Inner Borderland research on Palos Verdes Fault and San Pedro Basin, verbal communication.

Gorsline, D.S., De Diego, T., and Nava-Sanchez, E.H., 2000, Seismically Triggered Turbidites in Small Margin Basins: Alfonso Basin, Western Gulf of California and Santa Monica Basin, California Borderland, Sedimentary Geology, v. 135, issues 1-4, pp 21-35. 

Irwin, W.P., 1990, Quaternary deformation, in Wallace, R.E. (ed.), 1990, The San Andreas Fault System, California: U.S. Geological Survey Professional Paper 1515.

Normark, W.R., McGann, M., and Sliter, R., 2004, Age of Palos Verdes Submarine Debris Avalanche, Southern California, Marine Geology 203, Issue 3-4,pp 247-249

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Chapter 6

Southern California Bight

Discussion

The Southern California Bight is the ocean off the coast of southern California which covers the California Continental Borderland.   The term bight refers to an indentation of a coastline, so in this case it represents the indentation of the California coast, from Point Conception south to the Mexican border.   For the sake of clarification, bight is a geographic and oceanographic term, and borderland is a geologic term, but for coastal southern California, they refer to the same physical area.

Since the ocean water of the Southern California Bight is on top of the varied features of the California Continental Borderland, ocean circulation in the Bight is complex.   Surface and deep-flowing Bight currents are influenced by the locations of basins, islands, banks and ridges, as well as seasonal variations in in wind-flow velocity and direction.   Surface-current circulation is stimulated by the California Current, which promotes eddy formation within the Bight.   Deeper Bight circulation is associated with poleward current flow from the south, which enables flushing of the Borderland basins.

Circulation within the Southern California Bight

Southern California Bight (SCB) circulation is forced or stimulated by the California Current, the California Undercurrent, and to a lesser degree by offshore wind flow.   Additional circulation is by the Southern California Countercurrent and seasonal eddy currents that form within the SCB.

A. California Current      The California Current (CC) is an eastern boundary current of the North Pacific gyre.   It flows equatorward (toward the south) from high to low latitude as a broad, cool, low-salinity, nutrient-rich, and slow- moving surface current.   From Oregon south to Point Conception, the CC flows offshore of the continental shelf edge, keeping coastal waters there cool in temperature.   South of Point Conception where the Bight cuts sharply to the east, the CC flows roughly 100 miles offshore of southern California.   As it travels southward, it interacts with the relatively stationary Bight water.   This causes some of the California Current to shear off, forming a poleward-flowing counter current within the Southern California Bight.   During winter and spring, northwest winds can steer some of the CC into the northern portion of the SCB, forming vortices in the Santa Barbara Channel.

B. Southern California Countercurrent      The counter-current flow stimulated by the California Current moves poleward (toward the north) past the Channel Islands and southern California mainland.   Many oceanographers refer to it as the Southern California Countercurrent (SCC), but some prefer to call it the Inshore Current since it seems to flow most strongly closer to the mainland coast.   During the winter and spring, equatorward winds accelerate the flow velocity of the CC, causing it to flow more jet-like, with little shearing taking place into the SCB.   As a result, the SCC slows to its lowest velocity.   During summer and fall, winds relax, reducing the velocity of the CC, allowing more shearing from the CC into the water of the Southern California Bight.   This increases the flow velocity of the SCC which in turn promotes eddy development within the Bight.   General aspects of surface-ocean circulation within the Southern California Bight are shown on the diagram below, from the web site Southern California Bight.

 

B. California Undercurrent      The California Undercurrent (CU) originates near the equator off the coast of Baja California.   It is believed that it forms as evaporation of warm surface water increases salinity content, and therefore water density, producing downwelling from the tropics.   Some of that downwelling water flows poleward along the continental slope off the coast of Baja California, eventually traveling beneath the SCC, hugging the slopes of the mainland and islands of the Southern California Bight.   (Although the undercurrent is warmer than the overlying SCC water, its high salinity makes it denser than the Southern California Countercurrent.)   The UC has maximum flow velocity, averaging less than .4 inch per second, between depths of 300 and 700 feet.   It flows continuously northward to Vancouver Island, British Columbia.   

C. offshore wind      Strong offshore winds from mainland southern California can drag the surface-ocean water offshore, allowing localized shallow upwelling to occur close to shore.   The result of this upwelling is to chill surface water by five to ten degrees Fahrenheit, an unwelcome change for swimmers and surfers.   (On the positive side, offshore winds can improve the shapes of breaking waves, standing them up to form beautiful, curling waves.)

D. eddy currents      Eddy currents are natural vortices that vary in size from a few miles to 80 miles across.   The largest eddy, the Southern California Eddy (SCE), incorporates much of the water of the Southern California Bight in a slow counterclockwise flow shown in the diagram below.    Di Lorenzo (2003) states that recent data collected from the Bight does not show an active, southern portion of this counterclockwise eddy flow, so the SCE may not be a true eddy/vortex.   Future data collection and investigation will confirm the true nature of the SCE.

1. In general, eddy circulation within the Bight is strongest during the summer and fall, when equatorward winds relax, the California Current slows, and water shears away from the CC into the Southern California Bight.   This accelerates the flow velocity of the Southern California Countercurrent, improving the likelihood of eddy formation.   

2. As the diagram above illustrates, the Southern California Eddy carries surface water from near the coastal zone away from the coast, to the outer Bight/Borderland.   In so doing, it not only transports planktonic organisms and fine-grained terrigenous sediment (clay and silt), but also pollutants introduced into the Bight from coastal sewage and stream runoff.

3. Smaller eddies form where the SCC flows past islands and banks, forming the vortex or whirlpool effect so commonly seen in streams.   Alternatively, eddies can form where opposing currents interact, causing meandering of the currents and eventually evolving into cyclonic-style flow, or eddies.   Note that in a sense, eddies within the SCB are similar to hurricanes and tornadoes in the atmosphere: possess cyclonic flow and they promote vertical circulation within the ocean.  

4. The vortices/eddies formed in the Southern California Bight are generally less than 30 miles across, with limited life spans of a week to a month.   Discussed below are two examples of eddies formed by different mechanisms within the Southern California Bight.   The images are products of remote sensing of the SCB by satellites.   The black-and-white images are generated by satellites using synthetic aperture radar (SAR), which can detect roughness of the ocean surface - flatter ocean surfaces are due to reduced wind flow or surface-active substances such as oil, and rougher ocean surfaces are due to higher wind velocity/bigger waves.   The color images are produced by radiometer-scanning of the ocean, which detects ocean-surface temperature.   These sea-surface temperature (SST) images clearly reveal the temperature variations between different masses of water, showing the cold or warm cores of eddies.

a. The SAR and SST images below, from the web site Southern California Bight, show an eddy that formed off the the coast of southern California, between the mainland coast west of Santa Barbara and the northern Channel Islands, in 1994.   This 20 mile diameter eddy was formed as the CC and SCC interacted with each other.   The SST image clearly shows the temperature differences between the two water masses.   Eddy circulation was counterclockwise.

It is likely that the cold-water core of this eddy formed as cooler water, sheared from the California Current, became surrounded by warmer water of the Southern California Countercurrent as these to water masses interacted to form the eddy.

 

b. Also in 1994 but further southeast in the SCB, another eddy was recorded by both SST and SAR imaging.   This eddy had a diameter of 15 miles, and formed due to shearing of the SCC as it flowed northward past Santa Barbara Island.

Note that the core of this eddy is cold water, but it is entirely surrounded by warmer water of the Southern California Countercurrent.   It is possible that the cold water is being drawn upward from greater depth, much like a hurricane sucks surface air into the eye of the cyclone, forcing it into the atmosphere above.  

c. Some smaller-scale eddies are shown in the SAR images below.   These each have diameters less than six miles, and occurred in the San Pedro Channel near Santa Catalina Island.   These vortices were probably produced by shearing of the SCC as it squeezed between the southern California mainland coast and Santa Catalina Island.  

The SAR image above is a close up view of eddy F, from the prior SAR image.   Note the compressed shape of this eddy, a likely product of the forcing of the SCC through the San Pedro Channel between Palos Verdes Peninsula and Santa Catalina Island.

Obviously, circulation of the ocean in the Southern California Bight is complex!

 

E. basin flushing      The deep basins of the California Continental Borderland are within the oxygen minimum zone of the ocean, meaning that there is inherently little oxygen present within the basins for the metabolism of animals.   In addition, the basins are isolated from each other by banks, ridges, islands and low sills.   In general, the basins are so deep that they experience little horizontal current flow from the California Undercurrent.   This leads to stagnant water conditions at the bottoms of the basins, where biological activity and bacterial breakdown of organic matter cause severe oxygen-deficient (anoxic) conditions.   

Larger eddy currents within the Southern California Bight vertically circulate water from deep to shallow, and shallow to deep, alleviating the basins' anoxia to some extent.   This was probably the case in 1997 when oceanographers observed the flushing of the Santa Barbara Basin during a time when the California Current entered the Bight through the Santa Barbara Channel.   

Berelson (1991) indicates that, at least on occasion, flow variation of the California Undercurrent flushes out the Borderland's southern basins, enriching them with oxygen, permitting the return of bottom-dwelling organisms until anoxic conditions return.   These periodic changes may be related to El Nino events, although the connection is tenuous.   (The idea is that during an El Nino event, a thick lens of very warm surface water invades the Southern California Bight from the south.   This would have the effect of forcing the California Undercurrent to flow more deeply than usual, introducing oxygen-rich water into the deepest parts of the California Borderland basins.)  

Core sediment samples collected from basin floors clearly show the changes from oxygenated to anoxic basin-bottom conditions.   A period of flushing and oxygenation promotes biological activity on the basin floor, especially by organisms that burrow into sediment to consume preserved organic matter.   This disruption of sediment layering, called bioturbation, is easily recognized.   During long periods of anoxia, fecal pellets, clay and silt rain down on the basin floors.   Absent the burrowing organisms, this sediment forms thin, horizontal sediment layers on the basin floors characteristic of anoxic depositional conditions.   Below is a diagram showing the direction of flushing (see arrows) causing the change from anoxic to oxygenated conditions in the San Nicolas and San Pedro basins, as reported by Berelson (1991).

Wave Activity within the Southern California Bight

A. Roughly 60% to 70% of the wind waves that reach the Southern California Bight originate from the North Pacific Ocean near the Gulf of Alaska.   Wave diffraction at Point Conception adjusts swell direction from the north (a north swell), to a northwest swell.

B. Wave activity along the mainland shore of the Bight is muted by absorption and diffraction of swell by the Channel Islands.   The wave shadow created by absorption of the waves, and wave interference caused by diffraction can produce wide variabilities in wave heights behind the islands.   Typically, waves within the inner SCB are 30% to 50% smaller than waves in the outer SCB.

Inspect the CDIP swell map below and note the effects of wave absorption and diffraction on a northwest swell that entered the Southern California Bight in March, 2008.   By how much did swell height decrease from the open ocean to the mainland shore?

 

C. Both west and south swell can strike SCB shorelines more directly than the more-common northwest swell.   Notably, west and south swells experience roughly half the absorption and diffraction of the northwest swell.   Though less common than the northwest swell, west and south swells deliver more energy to the coast of southern California, generating more beach erosion, rip-current hazards, and longshore current activity.

Marine Biology of the Southern California Bight

A. The surface water of the SCB is rich in nutrients, in part because it is largely derived from the California Current which carries biologically productive, well-oxygenated waters southward from the Northern Pacific Ocean.   Locally, nutrients are introduced into the surface zone by upwelling currents stimulated by eddies and wind in the Southern California Bight.   Prior to modern-day fishing technology and techniques, the Bight had a thriving fishing industry, from the lowest to highest trophic levels.

B. Since the Bight's basins are primarily anoxic, bottom-dwelling (benthic) communities are sparse and poorly developed.   The dominant life forms there are mats of chemosynthetic bacteria which do not require oxygen for survival.   The occasional flushing events change the bottom chemistry of the basins, causing the chemosynthetic bacteria to move into the ocean-floor sediment until favorable conditions return.   During and soon after a flushing event, more typical benthic organisms like clams and foraminifera will populate the basin floors.

Whale carcasses that drop to the basin floors from above can stimulate unusual biological activity forming "island" ecosystems on the basin floors.   These massive carcasses become centers of chemosynthetic bacterial action, breaking down the whales soft tissues over a period of several months.   If anoxia is not too strong, a variety of scavengers will be attracted, forming a teeming but temporary basin ecosystem.

 

References

Berelson, W.M., 1991, The Flushing of Two Deep-Sea Basins, Southern California Borderland, Limnology and Oceanography, vol. 36, No. 6, p. 1150-1166.

Collins, C.A., Garfield, N., Rago, T.A., Rischmiller, F.W. and Carter, E., 2000, Mean Structure of the Inshore Countercurrent and California Undercurrent off Point Sur, California, Deep-Sea Res. II, 47:-782.

Di Giacomo, P.M., Holt, B. and Perry, B.D., 1998, The Southern California Bight, web site available at http://www.cnsm.csulb.edu/departments/geology/people/scbweb/homepage.htm.

Di Lorenzo, E., 2003, Seasonal Dynamics of the Surface Circulation in the Southern California Current System, Deep-Sea Res. II, 50: 2371-2388.

Hickey, B., 1998, Coastal Oceanography of Western North America from the Tip of Baja California to Vancouver Island; Coastal Segment, in The Sea, Robinson, A.R. and Brink, K.H., pp12, 947 - 12,966, Wiley and Sons.

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Chapter 7

Coastal Zone Pollution

The Hyperion wastewater treatment plant, coastal southern California, from Aerial Photography of Southern California web site.

Discussion

Globally, coastal-zone pollution is an increasing problem.   This is because the pollutants introduced into the coastal zone are generated by human activities - from individual and community habits and lifestyles, and industry that supports local and international economies.   Since Earth's human population continues to grow every day, the amount of pollution introduced into the coastal ocean continues to grow.   Nations with strong economies and environmental awareness have made great strides toward reducing their impacts on coastal zones, but many countries lag far behind in their efforts to reduce coastal-ocean pollution.

Coastal-zone pollution comes in a variety of forms, including visible solids such as floating trash, to invisible pollutants like DDT and bacteria.   There are many ways for pollution to enter the coastal ocean: from sewage outfall pipes, from streams that flow through urban areas or agricultural regions, from the atmosphere, and discharged or thrown overboard from ships.   These topics are covered in this chapter, with an emphasis on the coastal zone of the Southern California Bight (SCB).

Pollution From Wastewater Discharge

Historically, sewage generated by coastal cities was allowed to flow directly into the coastal ocean though channels, tunnels, or rivers.   The sewage was untreated, causing significant environmental problems and hazards in the coastal zone.   Beginning in the late 1800's, major coastal cities began treating their sewage before allowing it to enter the ocean.   Since then, most coastal cities have invested in centralized waste treatment plants to better deal with the sewage generated by their citizens.   

Today, wastewater discharge, or treated sewage, enters the ocean via outfall pipes that extend several miles from shore out into the coastal ocean.   These pipes are connected to municipal waste-treatment plants designed to separate most solid organic matter from water before it is allowed to flow into the ocean.   This process is called primary treatment.   The diagram below shows that even though wastewater discharge into the Southern California Bight has increased along with human population, the amount of solids released has decreased due to primary treatment of waste water.

Secondary treatment, while more expensive, removes nearly all solid organic matter and much of the harmful pathogens (bacteria and virus') still present within the primary-treated water.   Even though the wastewater is treated, it can still pose problems for coastal ocean animals where the water spews from the end of an outfall pipe as a plume of contaminated water.   The diagrams below are related to this topic.

The first diagram illustrates how an effluent plume of treated water rises where it mixes with the surrounding ocean water.   Ocean currents and waves, as well as wind can help with the dilution process.   Solids and heavy metals tend to sink downward to the ocean floor.   The second diagram is a flow chart revealing the different stressors introduced into the ocean from sewage outfall pipes and their potential impacts on the coastal ocean environment.

Instead of being released directly into the ocean, this treated water is sometimes used for watering public parks and golf courses, or it is injected into wells as oil is extracted from subsurface rock and sediment.   This last use for the secondary-treated water reduces subsurface compaction of sediment that would otherwise occur.   Prior to this practice, compaction due to oil extraction resulted in subsidence of land surfaces.   Locally, this occurred at the east end of Terminal Island, Port of Long Beach from the 1950's through the 1980's.    

A. In Los Angeles and Orange counties there are three principle outfalls connected to wastewater treatment plants that together release more than one billion gallons of wastewater daily.

1. Playa del Rey (the Hyperion Treatment Plant)      This plant handles the primary and full secondary treatment of approximately 425 million gallons per day (MGD) of sewage from coastal Los Angeles County.   The outfall pipe from Hyperion extends five miles offshore, releasing wastewater at a depth of 187 feet into the outer Santa Monica Bay.   This location is near the head of Santa Monica Submarine Canyon.   The aerial photograph below shows the Hyperion plant and a short stretch of the outfall pipe where it heads off shore into deeper water.

Outfall of organic matter and other contaminants from the Hyperion plant have seriously impacted benthic infauna (organisms that live within ocean-floor sediment).   The Amphioda benthic animal assemblage, shown in the map below, is displaced near the outfall areas, with pollution-tolerant organisms living closer to the outfall pipes.   (The sludge outfall pipe is now used when as a backup to the 5-mile outfall pipe.)

2. Palos Verdes Peninsula (Carson Treatment Plant)      This inland plant provides primary and secondary treatment of wastewater for southern Los Angeles County.   It processes some 400 million gallons of wastewater daily.   The outfall pipe for the Carson plant extends only 1.9 miles offshore from White Point, Palos Verdes Peninsula, releasing its load at a depth of 200 feet into the ocean near the edge of the continental shelf.

3. Huntington Beach (Orange County Treatment Plants 1 and 2)      These plants combine to treat a total of 276 MGD.    Currently, only 207 million of the 276 million gallons are receiving secondary treatment.   The outfall pipe for this facility extends four miles offshore, releasing outfall at a depth of 180 feet.   The goal of the Orange County Sanitation District is to achieve full secondary treatment of all wastewater discharge by 2012 (Armstrong, J., written communication).   Below is an excerpt from an Orange County Sanitation District web page pertaining to testing of coastal water quality associated with the Huntington Beach outfall.   The URL for this web page is: http://www.ocsd.com/environmental/ocean_monitoring_program.asp .

Ocean Monitoring Program The treated wastewater from our two treatment plants is released over four miles out into the ocean at a depth of two hundred feet below the surface of the water. To ensure that the marine environment and public health are protected, the Orange County Sanitation District has maintained an extensive ocean monitoring program for over 25 years. The results of this testing is gathered together each year in an annual report. The report is provided to regulators, the scientific community and the public through a published report, on the district website and through a series of public work shops. These reports are available in our Document Center. The ocean monitoring program is overseen by the United States Environmental Protection Agency, Region IX and the Regional Water Quality Control Board, Santa Ana Region. Testing Programs The Orange County Sanitation District routinely performs three types of ocean monitoring programs. Core Monitoring The core-monitoring program includes measurements, sample collection and analyses, and data interpretation to evaluate potential impacts of treated wastewater on the following: • Coastal water quality; • Sediment quality; • Benthic infaunal community health; • Fish and macro-invertebrate community health; • Fish tissue contaminant analyses; and • Fish health (including external and internal examinations and pathologies). Sampling locations include 17 offshore and 17 surf zone water quality stations, 49 stations to assess benthic (bottom-dwelling) organisms and sediment chemistry, and 9 trawl stations to evaluate fish and macroinvertebrate communities. Regional Monitoring Regional studies measure the environmental conditions within the Southern California Bight (the area from Santa Barbara to Ensenada, Mexico). These results provide valuable information that can be used to improve our understanding of regional-scale processes and provide a regional perspective for comparisons with data collected for the core program and special studies.   Special Studies As specified in the ocean release permit, the district conducts special studies to study important coastal issues and processes that are not addressed by routine monitoring. These projects study oceanographic and biological processes that enhance data interpretations and data quality of the core program.   Testing Methods Trawling Trawling is accomplished by dragging an otter trawl net behind the boat on the bottom at a specific speed and for a specified distance collecting fish and invertebrates as the net is towed along the bottom. OCSD Trawl sampling consists of semiannual sampling at nine stations in summer and winter surveys. All of the fish and invertebrates from each haul are enumerated, weighed and measured, and checked for external parasites or abnormalities. Some fish are also checked for internal pathologies or are saved for laboratory bioaccumulation analyses.   Sediment grabs Sediment grabs samples are collected using a Van Veen sampler that is designed to be lowed from a boat, impact the bottom and close upon retrieval to collect sediments. Separate samples are collected to assess sediment chemistry and to enumerate and identify organisms that are living in the sediment. Samples are collected at 10 stations quarterly and an additional 39 stations annually.   Mooring sampling Mooring stations collect long term (up to one year) of continuous data of currents, temperature, and conductivity to get a more comprehensive look at oceanographic conditions at a fixed location. This long-term data is used to complement the temporal water quality data that is collected as part of the core-monitoring program.   Water quality sampling Offshore water quality sampling includes three days per quarter sample collection of both discrete seawater samples and continuous oceanographic parameters at 17 stations ranging from 0.25 miles from shore to six miles offshore. Continuous data is collected through the entire water column including, data on depth, temperature, conductivity, pH, dissolved oxygen, water clarity, chlorophyll-a, and photosynthetically active radiation. The discrete samples are analyzed for ammonia and bacteria.   Surf Zone sampling Samples are collected in ankle deep water at seventeen stations along the shoreline in Newport Beach and Huntington Beach to assess swimming safety. These samples are analyzed for three indicator bacteria that the Orange County Health department uses to determine the presence of harmful pathogens. Surfzone sampling is conducted five days a week by OCSD staff and results are given to Orange County Health Officials who determine ocean swimming safety.

 

The diagrams below, from Ecology of the Southern California Bight (1993), show the Huntington Beach outfall location and concentrations of copper present in sediment samples collected by two different surveys.   Note the general northwesterly distribution of this contaminant, consistent with the flow of the Southern California Countercurrent and the California Undercurrent.   As expected, the graph indicates that marine life is significantly impacted near the diffuser attached to the end of the outfall, with species diversity increasing with distance from the diffuser.   It is interesting that the number of individuals and overall biomass decreases at a distance greater than one kilometer from this outfall pipe.   This suggests that the high concentration of certain outfall nutrients stimulates growth of a few organisms at the expense of the general shallow-ocean ecosystem near the diffuser.

]

The U.S. Geological Survey map of Long Beach, California below has the Playa del Rey, Palos Verdes, and Huntington Beach outfall locations highlighted.   Note that each outfall terminates close to the drop off to deeper water, near the head of a submarine canyon or at the edge of the continental shelf.

B. Historically, ocean water and sediment in the vicinity of outfall discharge areas has been highly polluted with pathogens (bacteria and virus'), organic matter (reduces water clarity and smothers benthic organisms), and toxins (heavy metals like zinc and copper, DDT, and PCB's).

1. DDT and PCB's are no longer being produced, and larger pathogens, heavy metals, and organic matter are largely removed from sewage wastewater by secondary treatment.   Chlorination and oxidation kill most other pathogens.

2. Unfortunately, a variety of chemicals continues to enter the ocean from sewage outfalls.   Plasticizers and pesticides contain compounds that inhibit fish endocrine systems, which regulate hormone production that controls glandular performance and animal growth.   

Metals like chromium and copper can become concentrated in ocean-floor sediment, impeding animal metabolism.   Floating grease and oil can foul surface water in the vicinity of the outfall plume, eventually moving ashore to popular beach areas.   The diagram below shows the progress in removing these pollutants from wastewater (influent flow) before their discharge (effluent flow) into the ocean.

 

Pharmaceutical waste (pharmwaste), especially estrogen, derived from the urine of women taking birth-control pills, is known to feminize male fish.   Intersexed animals are infertile, so pharmwaste could ultimately reduce fish production in outfall areas.   (Secondary treatment processes do not remove pharmwaste from effluent discharge water.)

3. Pollution Case Study: White Point Outfall, Palos Verdes Peninsula

a. From 1947 to 1971, the world's largest producer of DDT, the Montrose Chemical Company, discharged industrial waste into the Los Angeles County sewer system.   PCB's were introduced into the system by other industrial sources, and into the coastal ocean at the White Point outfall.

b. DDT (dichlor-diphenyl-trichlorethane) was an insecticide widely produced in the mid 1900's.   While very effective as an insecticide, DDT has severe effects on animals in the DDT-treated environment.   It interferes with cellular calcium transport, inhibiting the formation of eggshells in birds and reptiles.   DDT has been identified as a carcinogen as well.   Beginning in 1940, more than one billion pounds of DDT were used for agricultural purposes in the United States until it was banned in 1972.

c. PCB's (polychlorinated biphenols) are a group of compounds originally used as coolants for machinery, from 1930 to 1977.   PCB's act as immune-system suppressors, causing embryonic mortality and brain dysfunction in mammals.   PCB's are probable carcinogens.   Roughly two billion pounds of PCB's were manufactured in the United States before they were banned in 1977.

d. PCB's and DDT are organochlorine compounds little affected by water.   These harmful compounds persist in the environment for years, bioaccumulating in the fat tissues of lower-trophic level organisms, and gradually moving up the food chain due to predation by higher-level organisms.   (PCB's and DDT were identified by the Environmental Protection Agency as "emerging contaminants" back in the 1970's.   Current emerging contaminants are discussed later in this chapter.)   

e. PCB's and DDT in the White Point outfall area are largely buried by sediment now, but they continue to seep to the surface, affecting benthic organisms and some fish.   Bottom-feeding fish like white croaker and flatfish (Sole and Halibut, for example) caught in the coastal ocean near Palos Verdes Peninsula tend to have very high levels of these toxins, so it is strongly recommended that local fishermen and their families consume only small amounts of these fish.

Read the January 28, 2007 Los Angeles Times article related to this topic.   The map below is from that article, showing the affected area and toxicity of fish caught from particular sites off the coast of southern California.

Pollution from Surface Runoff

Most sediment and rock at Earth's surface is at least slightly permeable, allowing some rainfall/snowmelt to percolate underground.   In urbanized areas, much of the surface area is either covered by buildings or by streets and highways - referred to as surface hardening.   These human-made structures are largely impermeable, so surface water has little chance to percolate underground.   Couple this increased runoff due to surface hardening to the many forms of pollution from coastal cities and you have the recipe for placing a large amount of pollution into a coastal system in a very short period of time.   Exacerbating the pollution from surface runoff are accidental sewage spills that can send high concentrations of untreated human waste into the storm-drain systems of coastal cities.   

During 2007 Los Angeles County experienced more than 700 individual sewage spills.   Below is an excerpt from the Heal the Bay website pertaining to 2006 and 2007 sewage spills in Los Angeles County.

Sewage Spill Summary
There were 6 sewage spills affecting area beaches in LA County reported to Heal the Bay this past year. The biggest was an estimated 20,000 gallons of raw sewage spilled to Ballona Creek that resulted in beach closures from Dockweiler State Beach at Sandpiper Street north to Ironsides Street in Venice. A Culver City pump station failure in the early morning of August 8th was not reported to County Officials until early afternoon the next day. The beaches were closed by 2 pm on August 9th, approximately 12 hours after the spill began.

Two smaller spills resulting in short beach closures occurred in Malibu at Surfrider Beach (4 days) when a grease trap overflowed and wastewater drained to Malibu Lagoon, and at Venice City Beach at Topsail Street (3 days) caused by a sewage spill a few blocks from the beach.

Approximately 95,985 gallons of sewage entered the Los Angeles Harbor on May 24, 2006. After implementing a substantial increase in monitoring locations near the spill, the LA County Department of Health determined that the spill did not necessitate any beach closures. A 100 gallon spill by LACSD directly to the beach in Manhattan Beach at 26th and 27th Street on April 27, 2006 also did not result in a precautionary beach closure.

Locations in Long Beach’s Colorado Lagoon were closed for over two months due to high bacteria counts at multiple monitoring locations. Eventually, a leaking pump-out station was found to be the culprit. The south end of Mother’s Beach was closed for almost the entire month of October due to sewage contamination.

In a report released on January 24th, 2007, the Los Angeles County auditor-controller disclosed that more than 90 percent of sewage spills in LA County since 2002 were neither officially recorded nor cleaned up. Specifically, of the 208 sewage spills since 2002 (totaling 11.9 million gallons), only 19 were properly reported to the LA County Health Department, leaving over 9.7 million gallons of spilled raw sewage unaccounted for.

When a sewage spill has impacted the beach, the local California health agency is required by law to notify the media, establish a telephone hotline number to inform the public, and close the beach, prohibiting contact with the contaminated water. The beach must remain closed for at least 72 hours after the source has been identified, the spill ceases and sampling results indicate compliance with state standards.

Unfortunately, the audit showed that the Health Department closed beaches in only 2.6% of the more than 200 spills investigated. This means that countless swimmers, surfers and other beachgoers were unnecessarily exposed to potentially contaminated water.

The audit contained 15 recommendations to address the failures in the spill notification process, and we’re happy to report that these recommendations were adopted by the LA County Board of Supervisors at their January 30th meeting. Heal the Bay strongly supports these recommendations, which cover such diverse topics as setting guidelines and standards for maintenance of sewage systems and setting timelines and procedures for notification when a sewage spill happens.

California State Assembly Bill 800 (AB800), authored by Assembly member Ted Lieu, is an attempt to implement a few of the 15 recommendations stated in the Los Angeles County auditor-controller report. As originally introduced, the bill requires that: 1) local health officers or the directors of environmental health programs be included in the notification protocol for sewage spills into local receiving waters; 2) the notification of any sewage discharged into receiving waters be completed to appropriate agencies within two hours of knowledge of the spill; 3) failure to notify the appropriate agencies in a timely manner is subject to a fine; and 4) each of the nine Regional Water Quality Control Boards, the agency responsible for protecting and improving water quality in California, will be required to have a board member whose expertise is in the area of public health.

To date, the bill is before appropriations, and has been amended significantly. The bill now only requires notification of appropriate agencies, including the local health officer or the director of environmental health program, and fines for failing to notify the appropriate agencies in a timely manner, with no set time defined. Heal the Bay will continue to advocate that, at a minimum, the two hour notification requirement is adopted.

You can find an online article in our News Section that contains links to the copy of the full audit, the 15 specific recommendations, as well as related LA Times articles and an editorial.

Surface-runoff pollution can be introduced directly from coastal land that slopes toward the ocean, but it is usually introduced into the coastal ocean via streams/rivers, or via municipal storm drainage systems.   The locations where each stream or drainage pipe/channel empties into the ocean includes beaches that are prone to closure, as well as bays or harbors whose water quality can decline precipitously.    The pixellated SAR image below shows a storm-water plume from Ballona Creek where it flows into Santa Monica bay.   The polluted, but freshwater of the Creek floats on top of the ocean water, reducing radar scattering caused by the ocean waves, making the plume visible.   Which direction is the plume traveling? Does this coincide with the flow direction of the Southern California Countercurrent?

In poorly circulated portions of the coast, water quality may remain compromised for days or even weeks until tidal currents or wind waves/currents flush out the pollutants, or they become assimilated into the environment.   Two examples of this issue are provided.  

Los Angeles River to Long Beach Harbor       The aerial photograph below shows the Los Angeles River flowing into Queensway Bay where it mixes its brew of treated wastewater with stagnant ocean water of Long Beach Harbor.   Nitrates introduced by the river water can stimulate red tides (now referred to as harmful algal blooms, or HAB's) in the Harbor, which can persist for days to weeks due to its poor circulation.   During the local rainy season (December through April), flow volume of the Los Angeles River can increase 10-fold, placing a staggering amount of pollution into Queensway Bay and outer Long Beach Harbor.

The histogram below illustrates how pollutant levels within the Los Angeles River increase as it flows through Los Angeles County enroute to Long Beach Harbor.   Tujunga Boulevard is in the San Fernando Valley close to the river's source, and Willow Street is just a few miles inland from the Harbor.  

Surface Runoff into Marine Stadium      Long Beach Marina and Alamitos Bay receive some circulation from rising and lowering of tides, but are mainly circulated by water pumping from the Alamitos power plant in the middle distance on the first photograph below.   Marine Stadium, shown in both photographs, was used during past Olympic games for rowing events.   It is poorly circulated, so bacterial levels can build up to dangerous levels, forcing beach closures there.   Note the many houses and streets concentrated near Marine Stadium.   Slopes in the area drain toward the Stadium.

 

A. Generally, surface-runoff pollution is considered to be non-point pollution, that is it is derived from unknown sources or from unknown locations, or both.   A common non-point pollutant is nitrogen, a component of most fertilizers.   It could be derived from golf courses, parks, lawns, or agriculture.   In some coastal zones, all four sources are possibilities.

B. Streams/rivers and their tributaries carry surface runoff from inland areas to the ocean.

C. A storm drainage system is designed to speed runoff from urban and suburban areas where surface hardening enhances surface runoff.   Storm drainage systems include street gutters (shown in photograph below), underground pipes/tunnels, and open-air concrete-lined channels.   

In the Los Angeles County Flood Control District there are more than 50,000 street gutters, 2000 miles of underground pipes/tunnels, and 500 miles of open-air channels, including local rivers such as the San Gabriel, Rio Hondo and Los Angeles, whose channels are mainly concrete-lined.

The photograph below shows the concrete-lined Los Angeles River, and one of its tributaries, Compton Creek.   Flow direction is toward the upper right.

 

D. Within the Southern California Bight coastal zone only surface runoff from the Los Angeles and San Gabriel rivers is treated, but this just includes the so-called "normal flow".   This daily-flow content ranges from 60% to 70% treated waste water from up-river treatment plants.   During a storm event, this treated wastewater flow is overwhelmed by polluted urban runoff.   The aerial photograph below show the San Gabriel River during "normal flow", when it mainly carries treated waste water to the Southern California Bight coastal zone.   During the rainy season in Long Beach, flow volume can rapidly increase by 1000% as rain falls in the Los Angeles Basin and the San Gabriel Mountains.   The first significant rainfall of the season results in the "first flush", as surface pollutants are swept from the hardened surfaces of the Los Angeles Basin and transported directly into the coastal ocean.   Many beaches along the Los Angeles and Orange County coastline are closed for days after this event due to high bacterial counts.   The second photograph is a ground view of the San Gabriel River's normal flow of treated waste water.

Runoff from small coastal streams can have an impact on local beaches and coastal water, especially where they drain from agricultural fields or from golf courses, carrying excess fertilizer and bacteria into the ocean.   Where this occurs, signs are usually posted to warn beachgoers.

 

 

E. Runoff passing into the ocean from Los Angeles Basin storm drainage system is untreated, and usually contaminated with toxins (used motor oil, antifreeze, pesticides, fertilizer, and pet waste), as well as a variety of solid trash (plastic bags, and wrappers, cigarette filters, styrafoam packaging and cups, and plant materials).

Approximately 100 million gallons of contaminated water and debris pass through Los Angeles County's storm drainage system on each dry day; enough to overflow the Rose Bowl.   On a rainy day, the flow can increase to 10 billion gallons per day!   On the positive side of this matter, many storm-drain channels are now outfitted with trash-capture screens to reduce the amount of solid debris entering the rivers, and then into the ocean.   

The introduction of billions of gallons of untreated runoff severely impacts water quality in the coastal portion of the Southern California Bight.   When this occurs, beach closures are common, impacting the quality of life for residents and tourists alike, to say nothing of the negative effects of high bacterial counts on coastal-ocean inhabitants.   The Heal the Bay organization grades local southern California beaches on a regular basis.   Below is their 2007 annual grade report for Los Angeles County beaches taken from the Heal the Bay web site, http://www.healthebay.org/brc/annual/2007/counties/la/analysis.asp .

There are four agencies within the County of Los Angeles that contributed monitoring information to Heal the Bay’s Beach Report Card. The City of Los Angeles’ Environmental Monitoring Division at the Hyperion Sewage Treatment Plant monitored 34 locations (19 of which are monitored weekly; the other 15 are monitored more frequently). The Los Angeles County Department of Health Services monitored 31 locations on a weekly basis. The Los Angeles County Sanitation Districts monitored eight locations, six of which are monitored daily and two weekly. And finally, the City of Long Beach, Environmental Health Division, monitored 25 locations on a weekly basis. This includes the addition of two new monitoring locations in February 2006 — one in Alamitos Bay at Division Street and Bayshore and the other at the south end of Mother’s Beach. All monitoring programs except Long Beach collect samples throughout the year at the mouth of a storm drain or creek.

For additional water quality information visit the Los Angeles County Department of Health Services or the City of Long Beach websites.

LA County’s move to sampling at the mouth of flowing storm drains and creeks due to the Santa Monica Bay Beach Bacteria TMDL has contributed to the county’s grades being well below the state average. Heal the Bay believes that sampling at the outfall (point zero) of these drains and creeks gives a more accurate picture of water quality and is far more protective of human health. Statewide, most monitoring locations associated with storm drains or creeks are actually sampled at a substantial distance from the outfall.

Heal the Bay expected excellent water quality this past year due to the record drought and there were some notable improvements in the Santa Monica Bay. However, Los Angeles County had surprisingly poor water quality overall — by far the worst in the state — due in no small part to a dramatic decline in Long Beach water quality this past year. Both summer AB411 and year-round dry weather water quality was very poor in Los Angeles County this past year. Only 56% of the locations received an A or B for the summer months, and year-round dry weather was very similar with 57% As or Bs (Figures 11 and 12). There were some stretches of excellent water quality in western Malibu from Nicholas Beach to Zuma. The rest of Malibu, from Zuma Beach to Topanga Beach, exhibited very spotty water quality. The grades fluctuated from good to poor at almost every other monitoring location. Overall, Santa Monica Bay beaches scored fairly well with 52 of 68 (76%) scoring A or B grades during the AB411 months and just slightly lower with 49 of 67 (73%) scoring A or B grades during year-round dry weather. Poor grades for dry weather in Santa Monica Bay were received at Paradise Cove in Malibu (F), Escondido Creek (D), Solstice Canyon (D), Marie Canyon storm drain at Puerco Beach (F), Surfrider Beach (F), West Carbon Beach at Sweetwater Canyon (F), Topanga State Beach (F), Castlerock stormdrain (F), Santa Ynez stormdrain at Castlerock beach (F), Santa Monica Pier (F), Ballona Creek mouth (D), Redondo Municipal Pier (F), and Cabrillo Beach harborside at the lifeguard tower (F). Cabrillo Beach harborside at the lifeguard tower has actually earned F grades for all time periods over the last 4 years. Four of 5 monitoring locations at Avalon Beach on Catalina Island received poor grades for the AB411 time period this past year. As usual, Avalon Beach locations were not monitored year-round.

Stretches of beach with good water quality included all of Will Rogers State Beach, including Santa Monica Canyon, which finally scored a respectable B grade during the dry AB411 time period (after consistently being one of the most polluted beaches in the area for years). Clean water for all two miles of Will Rogers State Beach was a first in Beach Report Card history — a testament to Los Angeles City and County runoff diversions and the tougher summer beach water quality regulations. All beaches from the Pico/Kenter storm drain to Ballona Creek outlet (D) scored A grades for both the AB411 and year-round time periods. From Dockweiler State Beach at Culver Blvd. all the way to Manhattan State Beach at 40th Street received A grades as well. From the Manhattan Beach Pier drain all the way to the oceanside monitoring location at Cabrillo Beach, with the exception of Redondo Municipal Pier (F), received A grades for both the AB411 and year-round time periods.

As seen in our 2006 End of Summer Beach Report Card, Long Beach water quality last year was very poor. In fact, Long Beach had by far the worst dry weather water quality in the state. Long Beach exhibited only 12% A and B grades during both the AB411 and year-round dry weather. Forty percent of Long Beach monitoring locations received C grades and 48% received poor grades (D or F). The only A grade was at Long Beach City Beach projection of 54th Street. Two locations in Alamitos Bay received B grades. F grades were found at Belmont Pier (eastside), Long Beach City Beach at Prospect Ave., Alamitos Bay and 2nd Street Bridge and Bayshore, Mother’s Beach (two locations), City Beach at 72nd Place, and Colorado Lagoon. All of these locations, except one in Colorado Lagoon, scored A grades for the same time period in our last annual report. In fact, Long Beach hasn’t scored an F during AB411 since Colorado Lagoon scored one 5 years ago. A comprehensive sanitary survey needs to be performed for the City of Long Beach due to the magnitude and frequency of fecal bacteria exceedances this past year. Heal the Bay hopes to work with Long Beach officials as soon as possible to examine this dramatic decline in water quality.

The lack of rain this year didn’t seem to limit bacterial exceedances at Los Angeles County monitoring locations. In addition to having the poorest overall dry weather grades in the state, LA County also exhibited the worst wet weather water quality in California this year. Dropping from 34% on our previous annual report, the percentage of wet weather A and B grades was 29% this past year. Sixty-five of 92 (71%) sample sites received fair-poor grades, with nearly 50% of sample sites receiving a grade of F. Poor grades were scored as far up coast as Point Dume in Malibu and down coast to Dockweiler. Most South Bay beaches received good marks for wet weather. Of the 20 sites from Hyperion Treatment Plant to Cabrillo Beach oceanside, only 3 received poor grades. These were Manhattan Beach at 28th Street (F), Herondo Street storm drain (D), and the Redondo Municipal Pier (D). Every single monitoring location in Long Beach received an F grade during wet weather, undoubtedly due to the contributions of the Los Angeles and San Gabriel Rivers.

 

F. The following is a general accounting of the impact of surface-runoff pollution in the Southern California Bight coastal ocean.   

1. DDT and PCB's continue to leach from surface sediment in and around industrial areas, although only in trace amounts.   They have been detected in water samples from the mouth of the Los Angeles River at .07 parts per million.

2. Hydrocarbons from street oil/grease foul the water surface and discolor its appearance.   With prolonged exposure, this may harm marine mammals and birds.

3. Chemicals within antifreeze and pesticides are possible carcinogens and organ-impairment stressors.

4. Pet waste and sewage spills introduce coliform bacteria and a variety of pathogens into the coastal zone.   Sickening of marine mammals and surfers has been linked to these pollutants.

5. Solid waste fouls beaches, estuaries and marinas, and can impair plant/algae growth in coastal wetlands by suffocation or blockage of sunlight.   Marine animals can suffer or die from swallowing plastic bags and wrappers, as can coastal birds that mistake cigarette filters for food.   Below is a histogram showing some of the debris collected from the SCB ocean floor during a 1994 ocean-survey project.   Fourteen percent of all ocean-floor samples contain some form of solid debris. 

G. Emerging Contaminants      Emerging contaminants are toxic chemicals already present within the environment that are gaining recognition for the harm they are doing, or will potentially do, to the natural environment.   A long-running concern of environmental scientists is the hazard posed to coastal habitats by the flame retardant, polybrominated diphenyl ethers (PBDE's).   These widely used chemicals are incorporated into a variety of household goods, toys, construction materials and clothing, and apparently leach into groundwater and surface water from industrial centers and landfills, and eventually into the ocean.   A Los Angeles Times article from April 1, 2009 highlights this issue below.

Concerns raised About Coastal Levels of Flame-Retardant Chemicals

U.S. study finds widespread, high concentrations near Southern California and Chicago, as well as Alaska.

By Tony Perry
April 1, 2009

Flame-retardant chemicals that have been linked to reproductive and neurological problems in animals have seeped into coastal environments even in remote regions and have been found in high concentrations off populated areas such as Chicago and Southern California, a federal study revealed Tuesday.

"This is a wake-up call for Americans concerned about the health of our coastal waters and their personal health," said John H. Dunnigan, assistant administrator of the National Ocean Service, a branch of the National Oceanic and Atmospheric Administration, which released the report.
 

The study, part of the Mussel Watch Program, was the most comprehensive look at the nationwide presence of chemicals called polybrominated diphenyl ethers, used in a variety of commercial goods since the 1970s as a fire retardant.

High levels of the chemicals were found in sediment and shellfish samples in areas including the Pacific Northwest's Puget Sound; the Tampa-St. Petersburg, Fla., coast; New York's Hudson-Raritan Estuary; Lake Michigan off Milwaukee, Chicago and Gary, Ind.; and off remote shores in Alaska. The highest concentrations were near industrial centers.

The new report builds on a 1996 study that reported levels of the chemicals in limited areas.
 

The chemicals are credited with saving hundreds of lives each year from the spread of fire, federal scientists said Tuesday in announcing the study's results. But studies on animals have shown that flame retardants can cause thyroid hormone disruption and interfere with developing reproductive and nervous systems.

The chemicals enter the environment through runoff, improper disposal of household and electronic waste, and through sewage sludge. The chemicals also appear to be airborne.

"Action is needed to reduce the threats posed to aquatic resources and human health," Dunnigan said.

Production of the chemicals has been banned in several European and Asian countries. Eleven states in the U.S. have banned certain chemical combinations, and some manufacturers have instituted a voluntary ban. The chemicals are among those targeted in California's green chemistry initiative, which would replace substances thought to pose a health hazard to humans.

Steve Weisberg, executive director of the Southern California Coastal Water Research Project, hailed the federal study for helping to frame the issue of public health and "emerging contaminants."

Weisberg's agency, a joint-powers arrangement among 14 public agencies involved with water issues, has a partnership with the NOAA to study the chemicals' effect on mammals. The concern among scientists is that the chemicals may have reached the food chain in large quantities.

Preliminary studies suggest that pregnant women and their fetuses may be particularly susceptible to damage. The chemicals have been found in breast milk. But federal scientists have yet to determine at what level the chemicals pose a health threat.

Last year, a research team that included scientists from UC Berkeley found that Californians have more of the chemicals in their blood and in their homes than any other group in the country.

Levels in children exceeded those in their mothers, the study found.

High levels have also been found in the eggs of urban peregrine falcons near Los Angeles, Long Beach and San Francisco, according to a study released last year.

 

The United States Geological Survey has a web site devoted to emerging contaminants, some of which is included below.   To see the entire site go to: http://toxics.usgs.gov/regional/emc/index.html .

Emerging Contaminants In the Environment "Emerging contaminants" can be broadly defined as any synthetic or naturally occurring chemical or any microorganism that is not commonly monitored in the environment but has the potential to enter the environment and cause known or suspected adverse ecological and (or) human health effects. In some cases, release of emerging chemical or microbial contaminants to the environment has likely occurred for a long time, but may not have been recognized until new detection methods were developed. In other cases, synthesis of new chemicals or changes in use and disposal of existing chemicals can create new sources of emerging contaminants. Research is documenting with increasing frequency that many chemical and microbial constituents that have not historically been considered as contaminants are present in the environment on a global scale. These "emerging contaminants" are commonly derived from municipal, agricultural, and industrial wastewater sources and pathways. These newly recognized contaminants represent a shift in traditional thinking as many are produced industrially yet are dispersed to the environment from domestic, commercial, and industrial uses.   The major goal of the Emerging Contaminants Project is to provide information on these compounds for evaluation of their potential threat to environmental and human health. To accomplish this goal, the research activities of this project are to: (1) develop analytical methods to measure chemicals and microorganisms or their genes in a variety of matrices (e.g. water, sediment, waste) down to trace levels, (2) determine the environmental occurrence of these potential contaminants, (3) characterize the myriad of sources and source pathways that determine contaminant release to the environment, (4) define and quantify processes that determine their transport and fate through the environment, and (5) identify potential ecologic effects from exposure to these chemicals or microorganisms. Project research on emerging contaminants is being conducted within these five areas. The following links provide more detailed information. Analytical Methods Development Environmental Occurrence Sources and Source Pathways Transport and Fate Ecological Effects

 

Pollution From Boats

Ocean-going vessels of all sizes and nationalities ply the waters of the Southern California Bight.   These include small recreational sailing and motor craft, mid-sized fishing and research vessels, and large commercial transport and military ships.   Recreational boaters routinely throw waste overboard, usually solids that sink to the ocean floor.   In addition, large vessels can discharge ballast or sewage into the ocean, forming mobile polluted zones.     

A. All ocean-going vessels leak at least a little oil or fuel as they move across the ocean, leaving a thin petroleum slick behind them as they travel through the SCB.   The effect of this slick is to act as a surfactant, reducing wind's pull on the ocean surface, and therefore the formation of waves.   This phenomenon is illustrated in the aerial photographs below, showing ship traffic in the ports of Los Angeles and Long Beach and the smooth trail of water they leave behind.   Eventually, the petroleum can be carried shoreward by the dominant onshore winds in the Bight, fouling beaches and harming intertidal organisms.

 

B. Wind-powered vessels are responsible for only a small amount of pollution in the Southern California Bight.   With sails raised and engine off, they leak very little petroleum into the ocean, and no exhaust is emitted into the water and atmosphere.   In addition, the crew of sailing vessels tend to be more environmentally aware than their motoring equivalents, so they are less likely to pollute as they travel the ocean.

C. Recreational fishing in the Bight is from small, privately owned boats as well as from larger vessels that carry up to 50 paying fishermen and women at a time.   These vessels usually range over the inner and middle shelf of the SCB as they seek out prime fishing locations.   The main pollutants coming from such boats include fish guts, fishing gear (line, lead sinkers, and hooks), beverage bottles and cans, and fast-food wrappers and containers.   As indicated by the "Debris" histogram above, this marine pollution is common in Bight water.

D. Professional fishermen, using large fishing trawlers, often in fleets, work the outer Bight waters away from the continental shelf.   The principle solid pollutant from these vessels is netting, which floats on the surface or sinks to the ocean floor.   The larger nets can be several miles long, and can easily entangle pelagic (swimming) animals or compromise the functioning of benthic (bottom-dwelling) organisms.   Fish processing at sea can result in washing a variety of fish waste matter into the ocean.   Some secondary pollutants/hazards that fall overboard include hooks, lines, and wire.

E. Large ocean-going ships sometimes acquire ballast water in their holds to balance and steady the vessel as it travels the open ocean.   The ballast water is pumped on board while at dock in one port, and then released as it approaches its next port.   This is one way that non-indigenous and potentially invasive species are transported from one distant port to another.   Ships are now supposed to release their ballast water well before entering a port, but this practice is not always followed.   A query about this topic, to Dr. Robert Kanter with the Port of Long Beach, provides further insight to the introduction of non-indigenous species via ports worldwide.

"... in our last biological study, conducted in 2000, we identified 60 non-indigenous species. Although we cannot ascertain where they all came from we suspect many were introduced through ballast water or as fouling organisms on hulls. We do know that others have been introduced from people trying to conduct "new aquaculture", and disposed of "pets". We (Port of Long Beach officials) are currently conducting an update of our biological study. Current laws regulating ballast water and hull-fouling transport have reduced the potential for future introductions. It is not a major issue here today."

F. Large cruise ships can take as many as 5,000 people on a journey of a week or more.   This is a great way to experience the ocean, but that many people can generate a tremendous amount of sewage - up to one million gallons!   By law, cruise ships are required to discharge their onboard waste at least three miles off shore.   Even then, coastal winds and currents could direct the plume of untreated waste toward the shore, resulting in beach closures due to high bacterial counts.   In addition to sewage discharge, large vessels often have fuel leaks that can be hazardous to the coastal environment, especially when they occur in port.   The following link http://www.cruisejunkie.com/envirofines.html details some of the many violations committed by the crew of cruise ships around the world.   Below is a photograph of a cruise ship docked in Long Beach Harbor, outfitting for its next voyage.

Pollution From Offshore Drill Rigs

Offshore drilling for petroleum has been ongoing in the Southern California Bight since 1905.   As the demand for petroleum products continues to increase, pressure to step up exploration for offshore oil supplies continues to rise.   Presently, roughly 30% of the world's petroleum is being recovered from continental shelf and slope environments in the ocean.   This figure will probably increase with time as more-accessible terrestrial supplies play out and pressure mounts to further tap offshore petroleum reserves.   So, expect to see more offshore rigs in the coastal ocean of the SCB, as well as other coastal zones around the planet.  

In addition to the lack of aesthetic appeal, offshore drilling can cause significant environmental damage, with oil spills fouling entire sections of a shoreline.   But, much more common is localized pollution around the drill platform itself.   Below are photographs of drill platforms in the San Pedro Channel.   The third photograph shows the grand scale of the Channel, with three platforms and a ship sailing off into the distance.

A. Oil spills from offshore drilling rigs are usually small in scale, forming slicks that are biodegradable, given time.   (Note that crude oil, such as the oil extracted at the drill rig, is less harmful to the environment than refined oil, which is more reactive with water and organisms that it comes into contact with.)   Crude-oil slicks can form dense mats that float at the ocean's surface, shading photosynthetic organisms below and fouling the feathers of sea birds and the fur of sea mammals.   If the slick washes ashore, it will foul the beach with globs of tar-like oil.   The photograph below illustrates how this problem can become your problem.  

Here is a link to the description of a small oil spill that occurred in 2008 in the Santa Barbara Channel.   It came from the same drill platform that was responsible for the disastrous spill of 1969, which is discussed below.   The recent spill was cleaned up in just over a day, with little damage to the environment and animals.   You can read about this spill event in the linked Los Angeles Times article, Crews clean up 1,134-gallon oil leak in Santa Barbara Channel - Los Angeles Times.

The last major oil spill in the SCB was off the coast of Santa Barbara in 1969.   This event released 17,000 gallons of crude oil into the Santa Barbara Channel, killing thousands of marine organisms and fouling beaches all the way south to Palos Verdes Peninsula.   The coastal devastation of this event galvanized public opinion against offshore drilling, and led to the formation of the Environmental Protection Agency in 1972, and a national moratorium on offshore drilling that continues to the present.   Below are photographs related to this topic, taken from a UC Santa Barbara website.   The URL is: http://www.geog.ucsb.edu/~jeff/sb_69oilspill/69oilspill_articles2.html.   The photograph on the left shows an oil slick trailing away from an offshore drill rig.   The photograph on the right shows a seal pup covered with oil, lying on a Santa Barbara beach.

B. Less harmful but annoying is the solid waste that drops from a drill platform.   This includes 55 gallon drums, plastic pipe-thread connectors by the hundreds, tools and construction materials, and golf balls.

C. Untreated sewage is released directly into the ocean from drill platforms, altering the local biological community due to the small but constant release of organic matter into the ocean around the platform.

D. It should be noted here that the drill-rig structure can become a very positive aspect of marine life in the Southern California Bight by providing a hard, vertical surface onto which a variety of vertebrate animals attach.   A case for retaining rig structures, even after the rig no longer serves its original purpose is made by Tom Raftican in his workshop presentation "Rigs to Reefs", a portion of which is copied below.

Mineral Resources Management Division - Rigs to Reefs Workshop

Tom Raftican

~ From Transcript ~

Rigs to reefs is an excellent opportunity to examine and do something about that out of sight out of mind attitude that we've had with the ocean.  I’d like to share some of the ideas that Dr. Dick Glen had. Dr. Glen is the president of the San Diego Oceans Foundation, which is an affiliate member of the United Anglers of Southern California.

"Dear Tom, I wish that you would relay the following brief comments to the workshop attendees. They concern the large quantities of sea life associated with Southern California’s oil rigs and their importance to the Marine ecosystem. I am basing my comments on a lifetime as a professional biologist, aquaculturist and environmental analyst.

Riparian Concept  Much like a water course in Southern California, an oil rig serves as a highly productive habitat in a virtual desert. It should be given at least as much legal status as riparian habitat on land.

Seed source  The eggs, spores and larvae, and the many plants and animals associated with a oil rig, move throughout the Southern California Bight  and sea areas far away. For some species this is undoubtedly an extremely important source for maintaining stable populations. 

Oasis concept  Just as a spring in the middle of the desert provides the basis for a biological community, an oil rig performs the same function in the ocean. There are numerous spineless animals attached to the rig which form the beginning of a food chain which passes through to fish and on to birds and seals. Each rig can easily support hundreds of tons of sea life at one time.  Over the course of the seasons, the total production could easily amount to millions of pounds.

Rainforest analogy  It is now widely accepted that the uniqueness of much of the revered rainforest is due to vertical stratification. An oil rig is similar in that near the top, the plants and animals are involved in the primary production much as the canopy of a rain forest. The production falls to the levels below and eventually reaches the ocean floor. On the sea floor as a diverse biological community which depends on the continuing rain of sustenance from the top layers.

Spineless creatures need consideration too. It seems that only fish are deemed important when analyzing the biological significance of oil rigs. In fact the mussels, scallops, worms, anemones, starfish and many other invertebrates make up a mass of life much greater than the fish which is dependent on a oil rig. It is reasonable to expect at least 10 pounds of assorted sea life to be attached to each square foot of the legs and crosspieces down to a depth of 70 feet.

In summary, an unintended consequence of placing structures in southern California’s offshore waters is the creation of habitat which supports thousands of tons of sea life. Prior to seriously considering the removal of any oil rigs, society needs to know what and how much sea life will be destroyed. Furthermore, there will be biological consequences elsewhere, and that needs to be addressed.

Thanks for conveying my thoughts to the workshop attendees. Maybe some eyes will be open.

Sincerely Richard G. Glen, Ph.d."

In terms of the big picture, it's going to be very crowded in California.  We look at where we come from 1943 to the present. A recent estimate at 2020 our population will have a nearly 50 percent increase in California.

If you think our resources are strained right now, we talked before about endangered fish.  We have endangered invertebrates.  We have endangered mammals.  It is very necessary to enhance these resources in the future.  Rigs to reefs offers a tremendous opportunity to do that.   Thank you.

 

Pollution from Power Plants

Coastal power plants use ocean water to cool turbines that produce electricity for coastal communities.   The intake of ocean water, called once-through cooling, has a negative impact on marine organisms by physically withdrawing them from the natural coastal system.   The coolant water, warmed by 15° to 20º F as it passes through turbine condenser tubes, is discharged into the ocean via drainage channels or pipes.   This altered water affects local benthic, pelagic and planktonic communities.

A. Marine organisms are removed from the coastal ocean by entrainment, during which smaller organisms (plankton, eggs, larvae and juvenile fish) are sucked through the power plants' cooling systems.   Few organisms survive the experience of pressure changes, turbulence, and chemical treatment.   Larger fish, crustaceans, turtles and marine mammals may experience impingement, where they are trapped against screens designed to strain larger animals from entering the power plants' cooling systems.   Invariably, trapped animals die, and are eventually removed as waste matter.

The California Energy Commission's 2005 report on the environmental impacts of once-through cooling (OTC) for coastal power plants indicates that "most impacts are to early-life stages of fish and shellfish", and that power plants that intake and release water in coastal zones (bays, estuaries, and near shore) have a greater impact on ocean organisms than if water is removed and discharged from offshore pipes.   This is because coastal-zone water is typically more productive than offshore water.  

The environmental group California Coastal Keeper is promoting the conversion of these OTC power plants to safer technology.   One option is to convert the OTC power plants to recycling their coolant water, allowing heated water to drop through cooling towers before returning to the power plant.   Another option is to use air to cool power plants' turbines using condensers and fans.   Either approach will cause a significant rise in electricity rates for consumers.   Read a related article posted on the California Coastal Keepers' web site.  

Below is California Coastal Keepers' map of California's once-through cooling power plants.   Two are in Long Beach, along the San Gabriel River a mile or so inland from the ocean. 

 

B. The warmed power-plant water is regarded as thermal pollution, which drives away cold-water species from coastal waters.   The impact of this warmed water is greatest in bays and estuaries, such as Morro Bay and San Diego Bay, where there is little opportunity for mixing with the open ocean.   Secondarily, impact is significant where discharge is directly onto the ocean floor, causing scouring of the ocean bottom and reduction in benthic community diversity and abundance.

C. Chlorine, used to prevent microbial fouling of condenser tubes in a power plant's cooling system, reduces primary productivity in the local ocean and drives away fish from the warm effluent plume emanating from the discharge channel or pipe.   Typically, chlorine is flushed through a power plant system twice a day, for 20 minutes each time.

Note that discharge from the 13 Southern California Bight power plants is approximately seven times greater than the discharge from local wastewater treatment plants, and that combined, California's 19 coastal power plants use 17 billion gallons of ocean water daily!

Pollution from Natural Hydrocarbon Seeps

Natural hydrocarbon seeps originate from fractures in ocean-floor rocks.   This is especially true of the area offshore of Santa Barbara, where faulted and fractured anticline folds have been seeping natural gas and water into the ocean for hundreds, if not thousands of years.   Tar blobs wash ashore and foul local beaches, and tidepools near Goleta have been contaminated by hydrocarbons for years.   Below is a geologic profile of the California Continental Borderland just offshore of Goleta and Santa Barbara, illustrating the complex nature of the faults and anticlines of this portion of the Inner Borderland.   

The map below shows major areas of ocean-floor seepage of hydrocarbons in the SCB, including the Santa Barbara-area seeps as well as seeps offshore of Malibu and Redondo Beach/Torrance.

The SAR image below shows the extent of large oil slicks formed due to natural seepage from the ocean floor off the Santa Barbara coast.   Note the eddy circulation helping to break up the slicks.

Conclusion

Pollution within the Southern California Bight comes from a wide variety and number of sources, with varying degrees of negative impact on the coastal-ocean environment.   Although there is a heightened awareness and concern for the quality of our coastal habitats and their long-term well being, economic and population pressures are offsetting measures undertaken to mitigate human impacts in the SCB.   Unfortunately, coastal-ocean pollution is now a fact of life.   With education and determination, we can hope to lessen the harmful effects caused by human habitation and industry to coastal ecosystems.

References

Armstrong, J., 2008, Senior Scientist with Orange County Sanitation District, written communication.

California Energy Commission, Issues and Environmental Impacts Associated with Once-Through Cooling at California's Coastal Power Plants, June 2005, Staff Report, 66 pages.

Daily, M.D., Reish, D.J. and Anderson, J.W., 1993, Ecology of the Southern California Bight, University of California Press, Berkeley and Los Angeles, California, 926 pages.

Eichbaum, W.M. and panel, 1990, Monitoring Southern California's Coastal Waters, National Academy Press, Washington, D.C., 154 pages.

Steinhart, C.E and Steinhart, J.S., 1972, Blowout: A case Study of the Santa Barbara Oil Spill, Duxbury Press, Belmont, California, 138 pages.

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Chapter 8

Los Angeles and Long Beach Harbors

Discussion

The term harbor refers to the physical area protected from the open ocean waves and currents, whereas the term port links the harbor to a particular coastal city where significant amounts of cargo are loaded onto or discharged from ships, stimulating the local economy.   Locally, in the Southern California Bight (SCB), the largest and most productive harbors are called ports - the Port of Los Angeles, the Port of Long Beach, and the Port of San Diego.   An exception to this is Port Hueneme, a small but long-time commercial port that expanded its cargo capabilities in 1997 when it annexed the U.S. Navy's port facilities there.   Lesser SCB harbors such as those at Santa Barbara, Marina del Rey, and Oceanside primarily serve recreational vessels, with little trade occurring.   So, these harbors are not ports.

A harbor is a body of water that is deep enough to provide anchorage for ships, and that is protected from ocean waves and currents.   Natural harbors along the west coast of North America are rare, with San Francisco Bay and the many inlets of Puget Sound being notable exceptions.   In the Southern California Bight, the only truly natural harbor is San Diego Bay.   The rest of the SCB's harbors are artificial, relying on large rock walls, called breakwaters, to protect a portion of the coastal zone from waves and currents.   The coast behind the breakwater is then modified by a combination of dredging of wetlands to form channels and basins, and filling operations to create land for roads, storage, docks and piers.

Since this web book is oriented toward understanding the coastal systems and human impacts in the Southern California Bight, our focus will be on the artificial harbors of the SCB, and especially the major harbors/ports of Los Angeles and Long Beach.

Los Angeles Harbor

Los Angeles and Long Beach harbors are located within San Pedro Bay, which is protected from the dominant northwest swell by Palos Verdes Peninsula.  San Pedro Bay's coastal region was originally a tidally dominated coastal system, with broad, channelized mud flats and wetlands that were occasionally impacted by flooding of the Los Angeles River.   The map below, from Ecology of the Southern California Bight, shows the natural state of the Los Angeles/Wilmington/Long Beach coast prior to development of Los Angeles and Long Beach harbors.

Prior to 1871, ships visiting San Pedro Bay either anchored offshore and ferried goods ashore in small boats, or beached themselves during a low-high tide to unload cargo onto long wooden docks.   Below is a description, from the official Port of Los Angeles web site, of the conditions that existed for discharging cargo in the late 1840's, before the harbor was improved for trade purposes.

Still relatively undeveloped, the harbor did not offer deep-water access, forcing merchants to send small boats and rafts to meet cargo-carrying ships at anchor in the bay. This method was particularly cumbersome in transporting lumber which, as a result of the growing towns surrounding San Pedro, was in enormous demand. Once ashore, there was the added obstacle of expeditiously transporting the lumber to various markets in the region. Recognizing these shortcomings, one inexhaustible man was instrumental in bringing innovative changes to San Pedro Bay — changes that marked the first steps toward developing the bay into one of the great seaports of the world.

Phineas Banning arrived in Los Angeles in the 1850's, and soon set about to develop a harbor and port for the Los Angeles region.

The Los Angeles and San Pedro Railroad began service between San Pedro Bay and Los Angeles in 1869. This 21-mile stretch of track was the first railroad in Southern California and marked the beginning of a new era of development for the harbor region. As the nation recovered from the Civil War, and with business booming, Banning led the crusade to solicit Congress for the first harbor improvements. These included dredging the shallow Main Channel in 1871 to a water depth of 10 feet and constructing a breakwater between Rattlesnake Island (now Terminal Island) and Deadman's Island (formerly located near Terminal Island). In that year alone, 50,000 tons of lumber, coal and other types of cargo moved through the Port as the railroad became the dominant mode of transportation.

By 1900, port business had grown to the point that major infrastructure changes became necessary.

By the turn of the century, the City of Los Angeles had grown to a population of 100,000 residents. City officials knew that the existing infrastructure could not handle further growth in either population or commerce. With that in mind, the City in 1906 annexed a 16-mile strip of land on the outskirts of San Pedro and Wilmington — towns that three years later would join the City of Los Angeles. The Port of Los Angeles was officially founded in 1907 with the creation of the Los Angeles Board of Harbor Commissioners.

While City officials were primarily concerned with port infrastructure and how to encourage and utilize regional economic development, they also understood the importance of developing a port of global prominence. This was reflected in additional improvements to the harbor between 1911 and 1912. During that period, the first 8,500-foot section of the breakwater was completed, and the Main Channel was widened to 800 feet and dredged to a depth of 30 feet to accommodate the largest vessels of that era. Concurrently, Southern Pacific Railroad completed its first major wharf in San Pedro, allowing railcars to efficiently load and unload goods simultaneously.

Other notable developments for Los Angeles Harbor included the completion of the 3.5 mile long Middle Breakwater in 1937, construction of the Vincent Thomas Bridge which alleviated the need for the ferry system that connected Terminal Island with San Pedro, and construction of the largest single-user container storage facility in the world - Pier 400 - in 2004.   The photographs below provide different perspectives of the modern Port of Los Angeles/Los Angeles Harbor.

Long Beach Harbor

Long Beach Harbor is an extension of the harbor channels and infrastructure initially established in Los Angeles Harbor.   Long Beach Harbor was founded in 1911 when the State of California granted the City of Long Beach ownership of tidelands three miles inland from the high-tide shoreline along the coast of San Pedro Bay.   Channels and turning basins, dredged from salt marshes and tidal flats, were completed in 1916.   

Long Beach Breakwater      The final portion of the Los Angeles/Long Beach harbors breakwater system, the Long Beach Breakwater, was completed in 1949 eight years after construction began.   When initially conceived, the Long Beach Breakwater was designed to form protected water for Navy vessels.   During the years following World War II, increasing numbers of Navy ships were assigned to ports in Honolulu and San Diego, eventually leading to the closure of the Long Beach Naval Base and Long Beach Naval Shipyard on Terminal Island in the 1990's.   

Today the Long Beach Breakwater is seen by many as a negative for the City of Long Beach.   It breaks the force of incoming waves to the once-gorgeous beaches for which Long Beach was named.   Lacking the natural wave energy, little wave mixing and generation of longshore currents occurs, reducing circulation within this part of San Pedro Bay.   In addition, the breakwater acts as a trap for surface-runoff pollution coming from the Los Angeles River.   The combination of poor circulation, and introduction and trapping of pollutants in the harbor leads to the formation of harmful algal blooms and high bacterial counts within the harbor.   Notice how green the water is in Outer Long Beach Harbor in the photograph below.   This is likely a product of excess nutrients from the river feeding an algal bloom in the harbor.

Surfrider Foundation as well as other environmental advocates strongly recommend removing or reducing the breakwater to mitigate its harmful effects on the coastal ocean, and to allow waves to once again break along the beaches of Long Beach.   Almost certainly this would result in added tourism dollars for the City of Long Beach, and increase the enjoyment of this portion of the coast by the residents of southern California.   The vintage photograph below shows the surfing that used to be available along the Long Beach coast prior to construction of the Long Beach Breakwater.   (Photo credit is unknown.)

Below are three Surfrider Foundation proposals to reduce the negative impact of the Long Beach Breakwater on coastal Long Beach: 

flatten breakwater

Remove the top 20-30 feet of rock and spread the excess boulders flat along the ocean floor close to the area of the existing breakwater, thus creating an underwater marine sanctuary while still allowing ocean currents and pleasure craft to flow freely in and out of Alamitos Bay.

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convert to island

Gather boulders from the top 20-30 feet of the breakwater and create an island in the vicinity of the existing structure.   The island would serve as both a submerged and above-ground habitat for marine life and a bird sanctuary.

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recycle breakwater rocks

Re-deploy boulders from the top 20-30 feet of the breakwater to other breakwater projects currently underway or being considered by the Port of Long Beach.   The rocks which comprise the existing breakwaters in the Long Beach and Los Angeles harbor areas were quarried on Santa Catalina Island at substantial cost.   Redeploying this material within the harbor would significantly reduce the costs of projects planned or underway.   This approach to altering the breakwater would likely be spread over many years, as harbor projects arise and rocks are needed.   This would enable the monitoring of the outer harbor and changing of plans if necessary.

---

Opposition to reconfiguration of the Long Beach Breakwater comes from three different perspectives:

A. Opponents to removal/reduction of the Long Beach Breakwater cite the cost of removal as being prohibitive.   Surfrider Foundation estimates that the cost to reconfigure the breakwater would run between $20 and $30 million dollars.   However, this could be funded by Environmental Mitigation Accounts mandated by law when a project causes harm to an environment.   

B. The Port of Long Beach is in opposition to removal of the breakwater because it may want to expand into this portion of the harbor in the future.   Clearly, if the Long Beach Breakwater is gone, then port expansion will be severely impacted.

C. Shoreline residents of Peninsula Beach are opposed to this change because they fear flooding that might occur once the breakwater is removed.   Since flooding already occurs due to the combination of high tide and storm surge, their concerns seem to be unfounded.   Beach erosion, a long-term and significant problem along the ocean side of Peninsula Beach, may cease to be an issue once normal longshore current flow is re-established.   The longshore current will then carry sediment eastward from the rest of Long Beach, widening Peninsula Beach and reducing the possibility of flooding.   Currently, south swells produce a longshore flow that moves westward, taking sediment away from the southeast end of Peninsula Beach, narrowing the beach and exposing homes there to  flooding and wave damage.   This effect is illustrated in the photograph below.

In July, 2005 the Long Beach City Council voted to inquire about Federal interest in reconfiguring the Long Beach Breakwater, which is property of the Federal government.   At that time, California congressmen declined to support the inquiry, so it was never considered.   In July, 2007 the Long Beach City Council again took up the matter of reconfiguring the breakwater.   They voted to fund a reconnaissance study of the role of the Long Beach Breakwater on the Port of Long Beach and the Long Beach shoreline.   $100,000 was appropriated from coastal-project funds to consider the economic and environmental impact of the breakwater, its effects on water quality and beach erosion, and its significance regarding national security.   Only data previously collected is being used for this study. 

Meetings held during the summer of 2008 were open to all interested parties, and guided by engineers of the firm Moffat and Nichol Engineering, hired to do the study.   Many participants strongly favored altering the breakwater, but to varying degrees.   Most thought it wise to retain some of the breakwater, reducing its size by 1/3 to 2/3.   Some favored forming a series of small gaps in the breakwater, but concerns about complex wave interference patterns tip the balance to a simpler approach - removing the western 1/3 to 1/2 of the Long Beach Breakwater.   This would both reinvigorate wave action along the beaches of Long Beach and return longshore current flow to the coastal system of Long Beach outer harbor.   As of early 2009, Moffat and Nichol Engineering has not made a recommendation to the Long Beach City Council on this important matter.

Below is a June 2008 Los Angeles Times article which addresses many of the points made above concerning the Long Beach Breakwater.

Long Beach at Sea Over Breakwater Removal Plan

Some fear flooding if the barrier is removed, but others say waves would attract visitors to the city.

By Deborah Schoch, Los Angeles Times Staff Writer
June 30, 2008

Long Beach has been preening its oceanfront image for more than a decade by pouring money and support into a wealth of new projects on its shores: a $117-million aquarium, gleaming Miami Beach-style condominium towers, a waterfront shopping center with sea-themed eateries, such as Gladstone's and Bubba Gump Shrimp Co.

What's missing amid all this sea fever, some say, is a Southern California style seashore.

 

 

Long Beach Breakwater site

One of the world's largest breakwaters stands between Long Beach and the Pacific Ocean, reducing mighty waves to mere lake-like lapping along the city's beaches. Without surf to cleanse them, those beaches were recently graded among the dirtiest in the state.

Surfers, environmentalists and some residents believe that restoring the surf would improve coastal water quality and draw visitors to the shoreline. They want officials to consider altering or removing the 2.2-mile eastern portion of the 8.4-mile San Pedro Bay breakwater -- the portion that sits offshore from the city's downtown, Bluff Park, Belmont Shore and Naples.

Known as the Long Beach Breakwater, that piece helped protect the U.S. Pacific Fleet when it was stationed in the city. (Not accurate.   The Naval installation was already protected by the Middle Breakwater.)   After the Navy and its ships left in the mid-1990s, some began to wonder if the breakwater had become obsolete.

This month, the Long Beach City Council voted 6 to 2 to hire Moffatt & Nichol Engineers to conduct a $100,000 preliminary study of the federally owned breakwater, to be funded equally by the city and the California Coastal Conservancy.

Some local officials say that the key cause of the dirty beaches is not the breakwater but the Los Angeles River, which drains 51 miles' worth of trash, urban runoff and sewage into Long Beach Harbor. They said cleaning up the river, not just improving water circulation in the bay, would be a better solution.

The city's surf-free beaches are among the least popular in the region. Even families within walking distance drive their children to cleaner beaches in nearby Seal Beach and Huntington Beach.

"If you take the hottest day of the year and you go down to the ocean side of the beach, it's empty," said Councilman Patrick O'Donnell, who sponsored the June 18 motion to conduct the study.

Robert Palmer of Long Beach recalls that when he first moved to the city and bought a house three blocks from the ocean, he walked his 7-year-old daughter to the beach to test the water.

"She wasn't out there 20 minutes when she came back with two plastic bags around her legs," said Palmer, chairman of the local chapter of Surfrider Foundation, a national environmental group.

Surfer lore has it that the sport got its start in California in 1911 when two men returned from Hawaii with surfboards and began surfing at Long Beach. Early surfers ranked the city's beaches among the best for surf in Southern California, and the city hosted the first National Surfing and Paddleboard Championships in 1938.

Old black-and-white photographs show the city's pre-World War II beaches teeming with swimmers, surfers and sunbathers. Then came the breakwater. The Long Beach segment was finished in 1949, and the waves ebbed.

Some believe that a return of waves would bolster the city's economy by drawing more beachgoers and tourists and recast the former Navy town as more of a beach city. The Long Beach chapter of the Surfrider Foundation has suggested three options: remove a piece of the breakwater, create holes in it large enough to let in part of the surf or remove the segment's upper 20 feet and place it on the ocean floor as an artificial reef to foster sea life.

Now, C.P. "Bud" Johnson, a local retired engineer, is proposing lowering 1,800 feet of the breakwater in one or two spots to sea level at low tide, so water can circulate twice a day at high tide.

News of his 44-page plan broke last week on two local news blogs, one trumpeting it with the headline, "The Man Who Solved the Breakwater."

Even before the city's proposed study has begun, numerous concerns are being raised.

Councilman Gary DeLong, who represents Belmont Shore and other beach areas, opposed it, troubled by the lack of guarantees that federal funding would be available for further study.

Some wonder how changing the breakwater would affect navigation into the ports of Los Angeles and Long Beach, the nation's first and second largest seaports.

Long Beach port spokesman Lee Peterson said the facility had not taken a formal position on the breakwater issue. Ships can safely anchor outside the breakwater, although some prefer to anchor closer to shore for convenience, he said.

 

Terminal Island      Terminal Island (formerly Rattlesnake Island) is the heart of both port facilities.   During the early to mid 1900's docks, warehouses, fishing canneries and terminals were constructed as port business boomed.   U.S. Navy docks and piers established on Terminal Island during World War II were turned over to the Port of Long Beach in the late 1990's, then converted into container storage and crane terminals for efficiently unloading and loading cargo containers.    Note the large metal containers stacked on the docks next to the cranes in the photograph below.

Beginning in 1943, petroleum extraction from the Long Beach Harbor area gradually lowered the land surface there.   In 1945 this subsidence was recognized as a potential threat to some harbor facilities.   By the late 1980's, subsidence of the east end of Terminal Island reached 20 feet, subjecting it to flooding from the ocean.   Large dikes were constructed to keep this from happening.   Recent injection of wastewater into well holes has stemmed the subsidence to where it is no longer detectable.   The east end of Terminal Island received land-fill material in the late 1990's to raise it up to the level of the rest of the island.

The middle and outer portions of Long Beach Harbor began to expand in the 1940's, with piers F through J being added over a twenty-year period.   This massive land-fill project cost millions of dollars, but has formed the basis for a modern and efficient port complex.   Channels connect the inner and middle harbor areas to the outer harbor and open ocean.

Wave reflection within the small side channel in the middle of the photograph above, where white container cranes are located, caused docked ships to rock back and forth.   Construction of the hooked breakwater has dampened that effect, reducing the likelihood of damage to ships, dock and cranes.

Hydrography of the Harbor Complex

Movement of water within the harbors of Los Angeles and Long Beach is complex, but generally slow due to the protective nature of the external breakwater system and the many channels and terminals within the harbor complex.   Generally speaking, the hydrography of the harbors is as follows: the outer harbor regions are more energetic and have better water quality than the inner harbor basins and channels.   This is mainly due to the three gaps in the breakwater system, Angels Gate, Queens Gate, and the open eastern end of Long Beach harbor, which allow some movement of waves and currents between the open ocean and the outer harbors.   Secondarily, the Middle and Long Beach breakwaters are somewhat porous, enabling some wave surge and water movement to exchange from the open ocean into the outer harbor area.

A. water circulation in the harbors

1. The inner-harbor channels and basins are primarily circulated by tidal currents.   This circulation is sluggish at best, allowing toxic materials like fuel to settle and accumulate within sediment.   Freshwater inflow from residential and industrial channels introduce sediment and pollution into the harbor area.   Boat traffic keeps fine sediment suspended within the harbor, reducing water clarity.

2. The outer harbor is mainly influenced by shelf circulation, which is primarily eastward.   This weak nearshore current is a product of dominant onshore flow of wind, which drags surface water shoreward, and the Coriolis effect, which diverts the current toward the east.   The nearshore current enters the harbor through the gaps in the breakwater system, exiting the harbor from the large gap between the Alamitos Bay jetties and the eastern end of the Long Beach Breakwater.   Minor eddy currents spin off from the outermost harbor piers, promoting circulation to central portions of the harbor complex.

B. waves in the harbors

1. The dominant swell direction for waves that strike the Southern California Bight coast is from the north-northwest.   Waves refracting around Palos Verdes Peninsula tend to approach the breakwater at a slight angle from the west, with little wave energy entering the harbors through Angels Gate.   This is illustrated in the photograph below, showing the swell sweeping past Angels Gate.   If large, this cross-swell can be problematic for small vessels entering/exiting the harbors.   Queens gate opens directly southward, so waves tend to enter through this gap a bit more than through Angels Gate.   Due to diffraction, the waves' energy is spread throughout the Outer Long Beach Harbor area, reducing them to ankle height as they wash ashore.

2. A strong south swell, generated by distant storms off the coast of Baja California or beyond, can send significant waves passing through the breakwater gaps.   Though the waves lose considerable energy due to diffraction, which spreads out the wave front over a greater area, they can still churn up sediment in the outer harbor, clogging ship channels and forcing the ports to expend money for dredging operations.

A south swell also enters through the broad gap at the eastern end of Long Beach Harbor, between the east end of the Long Beach Breakwater and the jetties that protect the entrance to Alamitos Bay/Long Beach Marina.   The south swell diffracts from the end of the west jetty, focusing some of its energy where the jetty meets the beach, eroding and narrowing the beach there.   Longshore current produced as the south swell breaks at an angle to Peninsula Beach, carries sediment eroded from the end of the beach toward the northwest where it settles near Belmont Pier.   Annual and expensive beach reconfiguration replaces the the beach sand back to the southeast end of Peninsula Beach, shown below. 

 

3. Wind waves within the harbor tend to be small due to the short fetch of the harbor.   Yet, they help to mix the outer harbor enough to maintain a healthy level of primary productivity and therefore dissolved-oxygen content within the water.

 

C. freshwater influx into the harbor

1. The primary source of freshwater flowing into the harbor complex is the Los Angeles River.   It introduces significant sediment and pollution loads into the eastern portion of Long Beach Harbor.   Entrances to several small-boat harbors must be dredged after significant rainfall events, and local shorelines are posted as no-swimming areas year around.   (Outflow of the San Gabriel River at the far eastern end of Long Beach Harbor rarely impacts harbor water.   Instead, the San Gabriel River's pollution flows southeast to Seal Beach and beyond.)

2. For Los Angeles Harbor, the main source of freshwater is the Dominguez Channel, which drains the densely populated and industrialized area north of the harbor.   The Dominguez Channel enters Los Angeles Harbor at the inner harbor area, which is poorly circulated by tidal flux.   Needless to say, the inner harbor/Dominguez Channel water is highly polluted.

3. Rainfall over the Los Angeles coastal plain tends to spike pollution levels within the harbor complex as runoff flows directly into the harbor from piers and docks, or enters via the Los Angeles River or Dominguez Channel.   After significant rainfall it can take days to weeks for harbor water quality to return to normal conditions.

 

Impacts of the Ports of Los Angeles and Long Beach on the Southern California Bight

A. Initially, the negative impact associated with port development was destruction of roughly 15 square miles of tidal flats, wetlands and marshes of the Los Angeles River estuary.   Undoubtedly this has had a far-reaching effect on coastal ecosystems of San Pedro Bay, reducing local fisheries and habitat for indigenous and migrating water fowl.   Ultimately, the effects are unknown because no scientific studies were attempted before the coastal habitat was modified for human activities.

B. Water pollution from thousands of ships, a dozen canneries, a naval base and airfield, surface runoff from piers, and the past sewage outfall from the Terminal Island Treatment Plant have greatly reduced water quality within inner harbor channels and basins.   The better-circulated outer harbor is far less polluted.   The maps below, from Ecology of the Southern California Bight,  illustrate the improving conditions in the harbor area from the 1950's to the 1970's.   Water quality continues to improve, especially in the outer harbor regions.

C. The influx of nutrients, especially nitrates, from the Los Angeles River promote rapid plankton growth within Long Beach Harbor.   These algal blooms are most prevalent during the springtime when days are longer and temperatures are higher, aiding their explosive growth, called "blooming".   As the plankton die off, pigments in their tissues color the water brown to red, forming a so-called red tide.   Since the blooms are not associated with tides, they are now referred to as harmful algal blooms (HAB's).   Decay of the dead plankton removes oxygen from the water, threatening the survival of benthic organisms unable to flee the harbor.   A strong HAB event can travel as far south as Huntington Beach before it is dispersed by waves and currents.

Lesser HAB events can occur within inner harbor channels and basins.   These can be associated with illegal discharge of sewage from ships, or pollutants introduced by Dominguez Channel.

D. Water pollution from the ports is confined to the shelf of the Bight, carried southward by the dominant surface coastal currents, both longshore and nearshore.

E. Port air pollution, derived from ship and truck diesel emissions, is carried north and west over the Los Angeles coastal plain.   Together the ports form the single greatest source of air pollution in the region!   During offshore wind events, port pollution moves out across the SCB, with particulate matter settling onto the ocean surface.   Exact harmful effects to marine organisms are unknown, but low-level toxicity and the shading effects of pollution probably inhibit primary production within the surface zone of the Bight.

 

Impact Mitigation of the Ports of Los Angeles and Long Beach on the Southern California Bight

A. Reduction in port air pollution is an ongoing effort.   Plans are to hook up ships at dock to "green terminals", where ship-energy needs are supplied by onshore power plants versus a ship's onboard diesel generators.   Cleaner-burning diesel trucks, which transport containers from terminals to inland warehouses and distribution centers, are being subsidized to remove older more-polluting trucks from roads.   A new rail service has been proposed to ferry containers from the ports to an inland terminal where they would then be loaded onto trucks.   Victorville and Riverside have both been mentioned as possible terminal locations.

B. Little has been achieved to diminish pollution into the Los Angeles River, but future plans for river recovery and beautification will significantly improve river water quality by adding floodplain and wetlands to stretches of the river that are presently confined within a concrete channel.   Wetlands will slow the flow of water, enhancing natural filtration of particulate matter from the water, and the natural floodplain will enable percolation of water to recharge local groundwater supplies.

C. The Terminal Island Treatment Plant was recently upgraded, adding another level of treatment to remove bacteria before discharging treated water into the harbor.   The outfall location has been shifted from its original inner-harbor location to where it now discharges into the outer harbor, as shown on the map below.   Outfall "undertreatment events" are very rare, but when they occur contaminants are readily dispersed by outer-harbor current and wave action.

 

D. Removal of the Long Beach Breakwater, if and when it occurs, will restore northern/western swell influence along the coast of Long Beach, returning the normal southeastern flow of longshore current to the local coast.   

1. This combination of renewed swell and longshore current will:

a. efficiently dilute and spread out pollutants otherwise confined within the harbor.

b. reduce harmful algal blooms by rapidly dispersing the growing blooms, and with increased wave mixing, add oxygen to the water.

c. restore beach equilibrium along Peninsula Beach that was upset by construction of the breakwater in the 1940's.   To review, the breakwater has eliminated swell coming from a westerly direction, preferentially allowing southern swell to produce longshore current which has carried beach sediment from the southeast end of Peninsula Beach toward the northwest, where it settles near Belmont Pier.   The removal of the breakwater will enable the return of swell out of the west, reinvigorating the once-normal southeastern flow of longshore current.   This will allow the beach to return to typical width, which would be maintained by natural processes.

2. Potential negative effects of "sinking" the Long Beach Breakwater include:

a. damage to oceanfront homes and property due to a combination of high tide and big waves.   (It is likely that the natural widening of the beaches of Long Beach, due to renewed southeasterly longshore-current flow, would largely eliminate property damage from wind waves during a high-tide event.)

b. loss of protected water used by day-sailors and for overnight anchorage by ships of all sizes.

c. the upfront expense of dismantling the breakwater, which may exceed $50 million dollars.

d. loss of future economic development - port expansion - into eastern Long Beach Harbor.   (This is seen as a definite plus by residents of east Long Beach who are not pleased with the prospect of noise, light and air pollution that would come with port expansion.)

Other Harbors of the Southern California Bight

For many Californians and tourists, the smaller harbors of the Southern California Bight are the primary way they experience the ocean.   They provide ready access to the ocean for small sailing and power vessels, and for limited commercial-fishing and whale-watching businesses.   

Generally these small-boat harbors' entrances are oriented toward the east or south, away from the dominant direction of approaching waves.   Inspection of ocean-floor maps that show the bathymetry of local harbors reveals that many harbor entrances coincide with the upper ends of submarine canyons.   This is beneficial for two reasons: 1) the deeper water above the canyon will not allow waves to break at the harbor entrance because the waves don't feel bottom there, and 2) sediment will not accumulate at the harbor entrance because it is diverted into the submarine canyon and away from the harbor, negating the need for dredging.

Below are photographs of many of the small-boat harbors of the Southern California Bight, from Santa Barbara to San Diego.

Santa Barbara Harbor and Stearns Wharf      Note the spit that exists at the entrance to the harbor, formed due to longshore current that transports sediment, form west to east (left to right), along the outside edge of the breakwater.   Sediment is constantly dredged to keep the channel entrance open for harbor craft.

Ventura Harbor      Ventura Harbor opens to the ocean toward the west, so it is susceptible to the occasional strong west swell.   Note the two jetties that protect the harbor entrance from swells from the northwest and the south, and the breakwater offshore to break the force of the west swell that would otherwise cause problems for vessels entering or exiting the harbor.        

Channel Islands Harbor      This small harbor is similarly oriented like Ventura Harbor which is northwest of Channel Islands Harbor.   So, it is protected in a similar manner.   Note the large amount of sediment in the coastal zone here, a product of excessive runoff due to the wettest rainy season on record, in the winter of 2005.

Port Hueneme      This small port specializes in the rapid unloading of cargo, especially cars, for transport to the rest of the United States.   Hueneme Submarine Canyon comes right up to the harbor entrance, providing deep-water access for large ships.   Channel Islands Harbor is visible above (west of) Port Hueneme.

Marina del Rey      This is the principle small-boat harbor along the coast of Santa Monica Bay.   Its entrance opens toward the southwest, so it is protected like Ventura and Channel Islands harbors, with jetties and a breakwater.

Below is a reverse-angle view of Marina del Rey showing the layout of channels and docks, and the channel for Ballona Creek adjacent to the harbor's main channel.

King Harbor      King Harbor, at Redondo Beach, is protected by a long, curved breakwater.   When initially formed in the early 1950's, its breakwater was much shorter, providing only a small protected anchorage area for small boats (see the second, vintage photograph).   Sedimentation, from longshore current and wave diffraction reduced the anchorage area even further, so the breakwater was eventually extended to its present size.   Redondo Submarine Canyon comes right up to the harbor entrance, eliminating the need for dredging of the entrance area.

Below is another perspective of King Harbor as it is today.

Cabrillo Marina      This large marina is tucked into the extreme western end of Los Angeles Harbor.   It's protected by the San Pedro Breakwater, as well as its own small breakwater which guards against small wind waves created in Outer Los Angeles Harbor, and the rare storm event that sends surge and waves into the outer harbor.

Downtown Long Beach Marina      This small-boat harbor is inside of Long Beach Harbor, protected from the open ocean by the Middle and Long Beach breakwaters.   The Downtown Long Beach Marina has a long wharf/breakwater and smaller entry breakwater to protect against the rare storm surge event, and the small wind waves that often form within Outer Long Beach Harbor.   At its entrance is one of four human-made oil islands within Outer Long Beach Harbor.

Long Beach Marina      This small-boat marina is safely nestled behind Peninsula Beach, which itself is protected from the open ocean by the Long Beach Breakwater.   Access to the ocean from this marina is particularly easy, via the channel formed by the two jetties.

Anaheim Bay/Huntington Harbor      Anaheim Bay's jetties protect the entrance to the Naval Dock and Huntington Harbor, as shown in the first photograph below.   The second photograph shows the layout of well-protected Huntington Harbor.   Only sailboats that can lower (step) their masts can access Huntington Harbor, due to the low bridge crossing of Pacific Coast Highway over the channel to Huntington Harbor.

Newport Bay/Harbor      This small-boat harbor is protected by Balboa Peninsula, a large spit formed where the Santa Ana River empties into the Pacific Ocean.   The spit/peninsula is stabilized by a number of groins that break up the longshore current, trapping the sediment instead of letting it move on to the end of the spit.   The opening to this fine harbor is protected by jetties (lower right corner), which divert longshore transport of sediment out to the mouth of the Newport Submarine Canyon at the end of the jetties.   Note that much of the western harbor is not included in this photograph.   The smoke visible in the upper left corner of the photograph is from a wildfire at the northern end of the Santa Ana Mountains.

Dana Point Harbor   This tiny harbor is well-protected from the north swell by the Dana Point headland.   Refracting waves are muted by the long breakwater, which juts outward a bit to protect the harbor entrance from west and south swells.

The entrance to Dana Point Harbor, and Capistrano Creek and sediment plume.

Below is a better view of the layout of Dana Point Harbor.   It is a good launching area for kayaking this stretch of the southern California coast.

Oceanside Harbor      The next three photographs show the layout of Oceanside Harbor.   The right side of the harbor is open to the public, but access to the western side of the harbor is for the Camp Pendleton Marine Corps Base only.   Note the unusual T-shaped jetty easily visible in the second and third photographs.

The T-shaped breakwater is designed to mute wave diffraction, from a strong south swell, from traveling unimpeded into the public channel to the right side of the photograph.

Mission Bay and Marinas      Mission Bay is protected by a long spit that extends southward from Pacific Beach.   Two small-boat marinas are present within the calm bay water.

San Diego Bay marinas and piers    This large, natural bay includes six small-boat harbors and numerous piers for cruise and cargo ships, as well as naval vessels.   Though not as impacted by pollution as Los Angeles and Long Beach harbors, San Diego Bay does have its share of problems related to the population and industrial density along its shores.   It is naturally circulated by tidal currents, and occasionally flushed out when heavy winter rains send large volumes of freshwater into the bay via the Sweetwater and Otay rivers, and Chollas Creek.

Conclusion

The harbors of the Southern California Bight vary in size and configuration.   Except for the harbors naturally protected from waves and currents by spits or prominent headlands, local harbors employ breakwaters and jetties to protect harbor slips, docks and terminals from wave action.   Harbors that function as ports experience severe pollution problems, but help to power the southern-California economy.

References

Daily, M.D., Reish, D.J. and Anderson, J.W., 1993, Ecology of the Southern California Bight, University of California Press, Berkeley and Los Angeles, California, 926 pages.

Eichbaum, W.M. and panel, 1990, Monitoring Southern California's Coastal Waters, National Academy Press, Washington, D.C., 154 pages.

Phillips, C.A., 2003, Los Angeles Harbor Report, Chapter 1 Introduction.

Surfrider Foundation web site, http://www.lbsurfrider.org/ .

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Chapter 9

Coastal Ocean Food Resources

Discussion

Harvesting food from the ocean has been practiced by humans for thousands of years.   Historically, the primary approach has involved casting nets from the deck of a boat, or towing nets of varying shapes and sizes to harvest large quantities of fish from the ocean.   And for centuries, fish and oysters have been farmed in calm estuaries on most continents.   More recently, the ocean-food industry has developed modern techniques to catch wild fish and shrimp in the open ocean, and farm kelp, molluscs, crustaceans and fish on a large scale in the coastal-ocean environment.

Commercial Fishing Industry

A. Net-fishing, employed by most commercial fishermen,  is an efficient method of harvesting large quantities of fish from the ocean.   Unfortunately, the fishing industry has become so efficient that major fisheries have become depleted.   Consider these numbers, from the Monterey Bay Aquarium web site: "Between 1950 and 1994, ocean fishermen increased their catch 400% by doubling the number of boats and using more effective fishing gear. In 1989, the world's catch leveled off at just over 82 million metric tons of fish per year".    This intense pressure on ocean fish stocks is forcing restrictions on the fishing industry concerning the type and/or amount of fish caught , and even closure of entire areas to fishing.   Restrictions and closures on fishing can be directly related to commercial-fishing practices as well as habitat destruction. 

1. Fishing Fleets       Commercial fishing fleets work year-round, using scouting vessels and planes, sonar, and satellite photographs to locate large schools of fish.   Large fishing boats tow huge nets behind them.   Trawl nets can open up to greater than the size of the Statue of Liberty, catching everything in their path.   Worse still are huge drift nets that can be 25 feet tall and 50 miles long.   Now banned, but still used by rogue fishermen, drift nets entangle anything they touch, from desired fish such as tuna and salmon, to marine mammals and birds.   The accidental "bycatch" is removed from the net and thrown back into the ocean as trash.   This highly efficient and indiscriminate removal of marine animals from the world's best fishing areas has led to the collapse of some fisheries, with many more on the verge of crashing.   The first photograph below shows a shrimp trawler at work, with booms extended and cables attached to the net.   The second photograph shows a full fishing net about to be unloaded into the holds of a fishing trawler.

 

   

In the early 1990's, the Georges Bank fishery off the New England coast in the North Atlantic Ocean collapsed.   Historically, this region yielded huge catches of cod and halibut, but by 1992 local catch of these fish had dropped to nearly zero.   Tardy actions to restrict fishing in those waters came too late to allow the stocks of halibut and cod to recover.   

 

The same mistake is now being played out on the other side of the North Atlantic Ocean, where European fishers are efficiently removing young cod before they have the chance to reproduce!   It is estimated that trawlers cover every square meter of the Dutch continental shelf twice a year.   Similar pressures are being exerted in other fish-rich portions of the ocean every day, and the sustainable fishing yield from the ocean is now being exceeded.

The discussion above makes it seem that over-fishing occurs in far-away locations, but it also affects California's coastal ocean.   From 1950 to 1990, the abundance of White Sea Bass declined to only 10% of what it was in 1950.   This was due to the practice of draping huge, plastic-filament gill nets through offshore kelp forests.   This had a significant impact on White Sea Bass as well as many other fish of the Southern California Bight.   This practice was finally outlawed in 1990.

The salmon fishing industry has long provided jobs and an abundance of Chinook salmon for our dinner plates, at least until 2008.   Salmon require freshwater streams for spawning, with adults swimming many miles inland to lay their eggs or release sperm into water with ideal temperature and current conditions.   For thousands or years, the Sacramento River Delta and its tributaries have been the breeding grounds for a huge population of Chinook salmon.   Once hatched, juvenile salmon (called smolt) make their way to the Pacific Ocean where they live out their adulthood as pelagic fish.   The Los Angeles Times article below provides a vivid description of the problems facing wild salmon spawned from California rivers.

U.S. halts commercial salmon season  

(Los Angeles Times article from April 11, 2008, by Eric Bailey)

EUREKA, CALIF. -- -- Instead of preparing to hit the Pacific's wind-tossed waters next month, veteran fisherman Dave Bitts sat at the counter of a dockside restaurant on Humboldt Bay recently, mulling fate and a cloudy future. For the first time since the birth of the West Coast fishing industry 150 years ago, Bitts and other fishermen face a season without salmon.

Federal regulators, worried about sagging runs up and down the coast, agreed Thursday to cancel this year's commercial and recreational catch of Chinook -- the prized king salmon of the fish market -- off California and Oregon. The ban adopted by the Pacific Fishery Management Council after a weeklong meeting in Seattle marks the new low point for a trade enshrined in the West since the Gold Rush.

An aborted season will wallop coastal communities in which salmon has long been a financial and cultural mainstay. Repercussions are expected to ripple out, with the ban hurting not just fuel docks and tackle stores but also supermarkets and truck dealerships. In California, commercial salmon fishing is a $150-million business.
Hardest hit will be full-time fishermen like Bitts, a gray-bearded Stanford graduate who three decades ago chucked plans to follow his family into teaching. He preferred the sea.

Like most North Coast fishermen, a hearty but shrinking brotherhood scattered in harbor towns like Fort Bragg, Bodega Bay and Santa Cruz, Bitts depends on the salmon catch for more than half his income. After the last two dismal salmon seasons, he and other commercial fishermen knew 2008 would be bad.

The Sacramento River has in recent years been the West Coast's spawning powerhouse. While other rivers suffered, it became the backbone of the industry, with a productive run that reliably dispatched enough fish into the Pacific to keep the commercial fleet afloat and sport fishermen happy. But lately the number of Chinook returning to the river has been dropping. Scientists now predict that fewer than half the fish needed to ensure a sustainable population will return this fall.

Given these bleak realities, Bitts and many other fishermen are greeting the ban as a grim necessity for a livelihood that depends on the fickle nexus of Mother Nature and mankind. "Going fishing this year would be like a farmer eating his seed corn," Bitts said. "For a sliver of a season and a tiny catch, it's not worth it." Federal regulators approved a truncated salmon season for Washington and allowed a 9,000-fish catch of hatchery-raised Coho salmon off central Oregon.

A normal season in the West is long and prosperous, running from May to October, with more than 800,000 fish caught off California and Oregon. This year the season ended before it started. "Fishermen are born with an extra helping of hope," Bitts said. "But I never had much hope for this season." Now he and other fishermen are pushing hard for financial help and for the government to find a way to fix what ails the salmon.

Last week, Bitts and half a dozen peers flew to Washington to lobby for disaster relief. They warned that the economic hit they will take this year will eclipse that of 2006, when a sharply curtailed season required more than $60 million in federal aid to keep the commercial fleet from sinking in red ink. The fishermen also are aggressively promoting potential solutions -- such as better practices at hatcheries that raise juvenile salmon and environmental fixes for the ecologically challenged Sacramento-San Joaquin River Delta.

Federal scientists have laid much of the blame for the salmon slump on shifting ocean conditions and a flagging offshore food chain, possibly brought on by global warming. But fishermen contend that there are other culprits. "We've come to the conclusion there are a whole bunch of smoking guns," said Duncan MacLean, a Half Moon Bay angler representing fishermen at this week's meeting. Factors as unexpected as bridge construction -- in particular the underwater noise caused by pile-driving tower supports -- may have impeded tiny juveniles venturing to sea, MacLean said.

The fishermen also see trouble in long-enshrined hatchery practices. A federal hatchery in the state's far north releases baby salmon right into the upper reaches of the Sacramento River for a perilous 250-mile journey out to sea. Studies have found that in some years just 2% survived the trip, said MacLean, who believes the fish should travel by truck.

State hatcheries do haul juveniles by truck, dumping them beyond the delta near the entry to San Francisco Bay. The fish have traditionally been placed first in floating "net pens" to ease their adjustment to a predatory world. By 2005, however, the pens had fallen into such disrepair that state crews stopped bothering to use them. When the juvenile salmon were dumped into the bay, "it was like having a neon dinner sign up," Bitts said. Little fish quickly fell prey to sea gulls and striped bass, he said. Chastened, the state resumed use of the pens last year.

But the 800-pound gorilla remains the troubled Sacramento River Delta. The state's biggest estuary saw a marked decline in several fish species as water exports ballooned, peaking in 2005 at more than 6 million acre-feet. The pumps that divert river water into aqueduct channels are so strong they can suck up fish, including migrating juvenile salmon. Salmon may be benefiting this year from a federally ordered pumping cutback intended to protect the tiny delta smelt. Bitts and other fishermen want permanent cutbacks in the water exported to Southern California cities and San Joaquin Valley farmers.

They are pushing for the state to meet future water needs with conservation, recycling, increased groundwater storage and bolder efforts at desalinization. They would like to see Central Valley farmers shift away from water-intensive crops, and they want regulators to crack down on pesticides that taint delta water.

Salmon are survivors, Bitts said. They can rebound. But they need help. "It's painful to watch what's happening," he said. "To the fish and the fisherman."

Note:  On April 14, 2008 California State regulators banned commercial and sport salmon fishing from State waters that reach from the shoreline out to three miles off shore.   This action, in addition to the Federal government's decree that banned commercial salmon fishing from three to 200 miles off shore on April 11th, provides further protection to the declining salmon stock in the eastern Pacific Ocean.

2. There are many methods to catch fish in the ocean.   Some of these are covered below in an illustrated overview provided by the Monterey Bay Aquarium web site.

How Fish are Caught or Farmed Commercial fisheries use a variety of fishing methods and fishing gear to catch the fish we eat. Some are environmentally friendly; others aren't. Fishing Methods   Dredging Fishermen drag a heavy frame with an attached mesh bag—called a dredge—along the seafloor to catch bottom-dwelling shellfish. Some dredges have metal “teeth” along the base of the frame that act like a rake. As the gear is dragged along the seafloor, it stirs up shellfish, which flow into the bag. Water, sand or mud pass through the mesh. The durable bag is made of metal rings to withstand being dragged along the seafloor. Dredgers rake the seafloor for shellfish Most dredgers catch scallops, clams, oysters and other shellfish that live on the seafloor or burrow into mud or sand. Dredging damages the seafloor and results in unintentional catch Dredges cause significant habitat damage when dragged along gravel and rocky bottoms. Dredges also smooth out sandy and muddy bottom habitats, removing or smothering a variety of animal and plant life. Fish, sponges and other marine life unintentionally caught as bycatch are unlikely to survive under the weight of the heavy bag.     Gillnetting A gillnet is a curtain of netting that hangs in the water at various depths, suspended by a system of floats and weights, or anchors. The netting is almost invisible to fish as they swim into the gillnet. The mesh spaces are large enough for a fish's head to pass through, but not its body. As the fish tries to back out, its gills are entangled in the net. The size of a gillnet's mesh determines the type of fish it will catch Small mesh can catch small fish like sardines. Larger mesh can entangle fish such as salmon and cod, while allowing smaller species to pass through. Gillnets may accidentally entangle and kill sea turtles Gillnets entangle large numbers of marine mammals and sea turtles in addition to other marine life, resulting in a significant amount of bycatch. Habitat damage can occur when gillnets anchored to the seafloor are hauled in and become tangled on structures such as coral and rocky bottoms.   Harpooning Harpooning is a traditional method for catching large fish—and it’s still used today by skilled fishermen. When a harpooner spots a fish, he or she thrusts or shoots a long aluminum or wooden harpoon into the animal and hauls it aboard. Harpooners fish for open ocean swimmers Harpooners catch large, pelagic predators such as bluefin tuna and swordfish. Harpooning is an environmentally responsible fishing method Bycatch of unwanted marine life is not a concern because harpoon fishermen visually identify the species and size of the targeted fish before killing it.     Hook and Lining Hook-and-line fishermen use a pole (rod) and fishing line with one to several hooks. Handliners don’t use a pole—they simply hold a line in their hand. To attract fish, hook and liners use artificial lures or bait, “jigging” or jerking the line to simulate the motion of smaller fish. Sometimes they toss baitfish into the water to start a feeding frenzy among the fish. The catch is hauled in manually or with a mechanized reel. Hook and liners fish near the surface and down below Hook and liners target a variety of fish, ranging from open ocean swimmers, like tuna and mahi mahi, to bottom dwellers, like cod. Hook and lining is an environmentally responsible fishing method Fishermen can quickly release unwanted catch from their hooks since lines are reeled in soon after a fish takes the bait.   Longlining Longliners attract fish with a central fishing line that ranges from one to more than 50 miles (80 km) long. This central line is strung with smaller lines of baited hooks, which dangle at spaced intervals. After leaving the line to “soak” for a time to attract fish, longliners return to haul in their catch. Longlines at different depths attract different species Pelagic longliners hang their hooks near the sea surface to catch open ocean fish, such as tuna and swordfish. Demersal—or “bottom”—longliners float their hooks just off the seafloor to catch fish that live on or near the bottom, such as cod or halibut. Pelagic longlining can accidentally kill sea turtles and seabirds   The baited hooks of pelagic longlines attract a variety of open ocean swimmers, such as endangered sea turtles, sharks and other fish, resulting in wasteful bycatch. As the line is deployed into the water, seabirds dive for the bait and are ensnared on the hooks and drown. By sinking their longlines deeper, U.S. fishermen avoid the migratory paths of sea turtles. Other innovations to reduce bycatch include the use of “circle” hooks to ease the release and survivability of unwanted species and the deployment of longlines through a chute to reduce seabird interactions.   Purse Seining A purse seine is a large wall of netting that encircles a school of fish. Fishermen pull the bottom of the netting closed (like a drawstring purse), herding the fish into the center. Purse seiners either haul the net aboard or bring it alongside the boat to scoop out the fish with smaller nets. Purse seines are primarily used for schooling fish Fishermen use this method to catch schooling fish, such as sardines, or fish that gather to spawn, like squid. The most popular fish caught by purse seines are tuna used for canning. Purse seining for tuna results in large amounts of unintended catch   To locate schools of tuna, fishermen look for schools of dolphins (tunas often travel below dolphins) or set out floating objects (logs or rafts) to attract fish in the open ocean. The net encircles the school of tuna, but also catches the dolphins and a variety of other species, including sharks, sea turtles and juvenile fish. In response to public outcry over the deaths of hundreds of thousands of dolphins, innovations have been developed to release dolphins alive—but dolphin populations have yet to recover. Scientists believe this may be due to the stress of the chase and frequent capture.     Traps and Pots Traps and pots are submerged wire or wood cages that attract fish and hold them alive until fishermen return to haul in the gear. Traps and pots may or may not be baited, and they usually lie on the bottom—either singly or in a row. A rope runs from the trap or pot to a buoy floating at the surface, so fishermen can locate their gear. Traps and pots catch bottom-dwellers Traps and pots are often used to catch lobsters, crabs and shrimp. They're also used to catch bottom-dwelling fish, such as sablefish or Pacific rockfish. Most traps and pots are environmentally responsible, but have issues too   Baited traps may attract juveniles or unintended species. However, these animals can either escape through specially designed vents or be released alive once the trap is hauled aboard. Traps may damage seafloor habitats when large ocean swells and tides bounce the gear around. Hauling in a row of traps may also drag the cages along the seafloor, causing damage. Marine mammals can become entangled in the lines connecting the traps to the buoys.   Trawling/Dragging Trawlers tow a cone-shaped net behind a boat. They tow midwater trawl nets at various depths, ranging from just below the surface to just off the seafloor. They drag bottom trawl nets along the seafloor. Trawlers can add chains to the mouth of a net to stir fish like shrimp and flounder up off the seafloor and into the net. They can also add heavy tires—called “rockhoppers”—to help the net roll over rough, rocky seafloor areas without getting snagged. Trawling at different depths catches different animals Midwater trawlers catch faster-swimming schooling fish such as sardines. Bottom trawlers catch fish that live on or near the seafloor, such as cod, flounder and shrimp. Trawl nets catch everything in their path and can damage the seafloor   Pelagic trawlers often accidentally catch endangered sea turtles, juvenile fish and other unwanted species, resulting in a significant amount of bycatch. Trawlers (such as U.S. shrimpers) can reduce bycatch by adding turtle excluder devices and bycatch reduction devices to their nets, which allow sea turtles and unwanted fish to escape. Dragging nets along the seafloor can damage or destroy fish habitat. Bottom trawlers can minimize habitat damage by avoiding rocky or coral habitats and ceasing the use of rockhopper gear.   Trolling Trolling is a hook-and-line method that tows fishing lines behind or alongside a boat. Fishermen use a variety of lures and baits to “troll” for different fish at different depths. Trollers catch fish that will follow a moving lure or bait Trollers catch fish that will follow a moving lure or bait, such as salmon, mahi mahi and albacore tuna. Trolling is an environmentally responsible fishing method Fishermen can quickly release unwanted catch from their hooks since lines are reeled in soon after a fish takes the bait.

 

3. Habitat degradation       Habitat degradation within coastal environments and inland waterways has led to the reduction of breeding and nursing of small fish and crustaceans, which compromises the balance of coastal and open-ocean marine animal communities.   Couple the eradication of wetlands, as humans have drained and filled low-lying coastal areas for subdivisions and commercial ventures, with the modification of river hydrography discussed in the "U.S. Halts Commercial Salmon Season" article above, and it is obvious that human activities are degrading the health of ocean ecosystems.   Then factor in the effects of coastal-ocean pollution, global warming and the pressures from the fishing industry and it's not surprising that wild fish production and catch is on the decline worldwide.   This disturbing news is compounded by the fact that global demand for fish continues to increase in lock step with the growing human population on Earth!   The Los Angeles Times article below examines the critical issues related to salmon runs and fisheries of coastal California.

Sharks vs. Salmon

Decades of legal and political stalling have stymied protection of the fish and spawned a crisis.

By Paul Vandevelder
May 18, 2008

Last month, while late-winter storms pounded the Cascade and Sierra mountains and flooded dozens of salmon streams in the Pacific Northwest, members of the Pacific Fishery Management Council huddled around a table in Seattle and pored over marine biologists' latest predictions for West Coast salmon. The news was shocking: The spring and summer runs of chinook salmon, once numbering in the millions, in California's Sacramento River had dwindled to a few thousand. The message in the data was unmistakable: Like many of its cousins to the north, the Sacramento chinook could be extinct within a few seasons.

In response, the council canceled all summer commercial salmon fishing off the California and Oregon coasts, a projected $200-million hit to the industry and the coastal communities that depend on it to survive. But more than economics was at stake. The salmon is the coastal ecosystem's "keystone" species, one on which more than 500 other species depend for their own survival.

Unfortunately, the salmon fishing moratorium cannot possibly undo decades of political mismanagement of the region's aquatic resources. The fishermen and scientists know that the salmon's long-term survival will depend on overcoming the four horsemen of its looming apocalypse -- wildly fluctuating ocean conditions, habitat degradation, widespread agricultural pollution and dams. The question is whether the politicians will get out of the way and let the scientists run the show.

Congress anticipated that they wouldn't, so it pinned the efficacy of the 1973 Endangered Species Act on scientists, who could identify and implement the environmental measures that would support the biological needs of the fish. Unfortunately for the salmon, that's not how the law has worked out. A generation of politicians has devised myriad ways -- through lawsuits, stalling tactics and endless "follow-up" studies -- to get around the scientists and protect such industries as agriculture, aluminum smelters, barge operators, loggers and power producers. This endless political "logrolling," as lawyers call it, is a big reason why salmon populations have continued to decline for 30 years.

The Klamath River in southern Oregon flows through the center of a textbook case of logrolling. In the early 1980s, the Klamath Indians sued the state of Oregon to ensure that sufficient water was flowing in the river so that oceangoing fish, including salmon, could get to the ocean and back. The Indians depend on the fish for their economic and cultural survival.

 

But farmers who depend on diversion of the river's dam-captured water to irrigate their crops joined the state of Oregon to fight the suit. Although the farmers and Oregon lost in federal court, the case was far from over. The farmers brought two more suits -- encouraged and supported by regional and national politicians -- in hopes of keeping a larger share of the river's water. They lost both times, but throughout the legal contests, the water levels on the Klamath remained about the same, and the fish counts continued to plummet.

Nor did the setbacks in court stop the farmers from trying to keep the scientists at bay. Following the promptings of scientists, a federal court in 2002 ordered water spilled from dams on the Klamath to help juvenile fish reach the sea and to help adult fish migrate upstream. Outraged farmers prevented the spill. Then the Bush administration stepped in to restore peace and resolve the dispute. But while negotiations between the tribes and the farmers were stalled, the Interior Department withheld water from the river, a decision that played a significant role in the death of 33,000 adult chinook salmon on the rocks of the lower river.

Now it seems that the days of logrolling may soon be over. For many years, Don Chapman, the federal government's chief biologist on the Columbia River in the states of Washington and Oregon and a highly influential salmon expert, had argued that salmon and dams could coexist if more money was spent on making dam turbines more fish-friendly, upgrading habitats and improving "fish slides," which help salmon get around dams. Then in 2006, he dramatically reversed course and announced that dam removal was the only solution for pulling salmon from the jaws of extinction.

Chapman based his new opinion on an analysis of what could be done about the factors that threaten the salmon's survival. This is what he found.

* Wildly fluctuating ocean conditions: In the short term, scientists are powerless to stop them because they result from global climate change. They can only hope that salmon stocks are resilient enough to survive the new perils of predation and hypoxia (reduced oxygen content in the water) on continental shelves.

* Widespread agricultural pollution: If all agricultural and industrial pollution stopped tomorrow, the fact is that chemical toxins have been warehoused in millions of cubic yards of sediments that have been collecting behind dams for more than 50 years. There are no quick ways to cleanse those sediments.

* Habitat degradation: The billions of dollars spent on habitat enhancement over the last 30 years have done very little to improve fish counts. The value of improved spawning grounds are reduced to zero if the fish can't get to them.

All this led Chapman to conclude that removing dams that block salmon from reaching critical spawning habitats and the ocean is the only realistic way to save the salmon.

But will the politicians allow them to be removed?

They may have no choice, because U.S. District Judge James A. Redden, the special master of the Columbia River basin in charge of enforcing the Endangered Species Act in the Pacific Northwest, will probably have the last word on the fate of the salmon. After lambasting the 2006 salmon protection plan from the Bush administration, which is charged with enforcing the act, as "shameful," Reddin said that he would not rule out dam removal to fulfill his obligations under the law and save the salmon.

Any day now, Reddin is expected to rule on the administration's latest proposal for salmon recovery. The question he faces is whether the time has come for the courts to let science trump politics. If the answer is in the affirmative, perhaps the salmon will not go the way of the dodo bird on our watch.

 

B. Local commercial-sport fishing in the Southern California Bight has diminished as fish have become progressively depleted over the past 100 years.   Once-vast stocks of small fish such as sardines and anchovies were removed during the 1950's and 1960's by local fishing fleets to be ground up for oils and meal to feed livestock.   This undercut the food supply to higher-trophic fish, causing their numbers to dwindle.   Now, the main catch for local sport fishermen is bass, bonito, halibut, squid, yellowtail tuna, mackeral and rock cod, accomplished from the ends of piers or from breakwaters, or from the decks of sport-fishing boats.

Little remains of the abalone and urchin industry due to overexploitation through the 1970's.   Legislation passed in California in the 1970's now protects California's nearshore waters from most forms of harvesting, allowing abalone to slowly rebound in abundance.

Lobster trapping and free-diving is still permitted during a brief season.   Curiously, the region of the Southern California Bight with the best lobster diving is along the breakwater system for Los Angeles and Long Beach harbors, where lobsters up to two feet long have been removed by bold divers at night, using just a flashlight and their bare hands.

 

Ocean Farming Industry - Mariculture

Mariculture, also known as aquaculture, is the growth of marine organisms in a controlled environment.   This farming of marine algae and animals is providing an increasing amount of food for human consumption, coinciding with the decline of wild catch in the world ocean.   Today, mariculture produces half of all the seafood consumed on Earth!    Since ocean farming can be labor intensive, and it generally is best done in areas protected from large, destructive waves, mariculture is a coastal-zone industry, and one that has many negative impacts on coastal-ocean habitats.   

A. Here are some facts about the mariculture industry:

1. Worldwide, mariculture production is increasing by 8% annually.

2. In the United States, annual income from mariculture exceeds $150 million dollars.

3. In Asian coastal waters, shrimp mariculture has an annual value of $10 billion dollars.

4. The United States ranks third in the world as a consumer of seafood, but only 11th in worldwide ranking of mariculture production.

B. Fish farming is projected to become the largest segment of the global mariculture industry.

1. Ideally, fish farming will reduce the pressures on wild fish stock, allowing them to rebound from over-fishing and the effects of environmental degradation.

2. Practically, fish farming tends to occur within bays and estuaries where fish are raised in pens or cages.   The intensive concentration of feed, medicine and fish waste can:

a. spur the spread of disease and pests through the crowded penned-fish population.

b. alter fishes' chemistry in unnatural, undesirable ways.

c. harm the local marine environment.

 

3. The Monterey Bay Aquarium web site provides illustrations and descriptions of different types of fish mariculture. 

Open Net Pens or Cages Open net pens and cages enclose fish in offshore coastal areas or in freshwater lakes. Salmon and tuna are typically raised in net pens or cages. What are the issues? Waste from the fish passes freely into the surrounding environment, polluting wild habitat. Farmed fish can escape and compete with wild fish for natural resources. Escaped fish can interbreed with wild fish of the same species, compromising the hardiness of the wild population. Diseases and parasites can spread to wild fish living near or swimming past net pens.

Ponds Ponds enclose fish in a coastal or inland body of fresh or salt water. Wastewater can be contained and treated. Shrimp, catfish and tilapia are some of the most common species raised in ponds. What are the issues? The construction of shrimp ponds in mangrove forests has destroyed more than 3.7 million acres (1.5 million hectacres) of coastal habitat important to fish, birds and humans. The discharge of untreated wastewater from the ponds can pollute the surrounding environment and contaminate groundwater.

Raceways Farmers divert water from a waterway, like a stream or well, so that it flows through channels containing fish. Farmers usually treat the water before diverting it back into a natural waterway. The government requires strict regulation and monitoring of on-site and nearby water quality. In the U.S., farmers use raceways to raise rainbow trout. What are the issues? If untreated, wastewater from the raceways can contaminate waterways and spread diseases. Farmed fish can potentially escape and compete with wild fish for natural resources. Escaped fish can also interbreed with wild fish of the same species, compromising the hardiness of the wild population.

Recirculating Systems Recirculating systems enclose fish in tanks, where water is treated and recirculated through the system. Almost any finfish species such as striped bass, salmon and sturgeon can be raised in recirculating systems. What are the issues? Recirculating systems address many environmental concerns associated with fish farming: fish cannot escape, and wastewater is treated. However, recirculating systems are costly to operate and rely on electricity or other power sources.

 

4. Read the Los Angeles Times article below about farm-grown salmon to learn more about the negative effects of fish farming on the coastal ocean and local inhabitants.

Fish Farms Become Feedlots of the Sea

Like cattle pens, the salmon operations bring product to market cheaply. But harm to ocean life and possibly human health has experts worried.

By Kenneth R. Weiss, Times Staff Writer
December 9, 2002

PORT McNEILL, Canada -- If you bought a salmon filet in the supermarket recently or ordered one in a restaurant, chances are it was born in a plastic tray here, or a place just like it. Instead of streaking through the ocean or leaping up rocky streams, it spent three years like a marine couch potato, circling lazily in pens, fattening up on pellets of salmon chow. It was vaccinated as a small fry to survive the diseases that race through these oceanic feedlots, acres of net-covered pens tethered offshore. It was likely dosed with antibiotics to ward off infection or fed pesticides to shed a beard of bloodsucking sea lice. For that rich, pink hue, the fish was given a steady diet of synthetic pigment. Without it, the flesh of these caged salmon would be an unappetizing, pale gray.

While many chefs and seafood lovers snub the feedlot variety as inferior to wild salmon, fish farming is booming. What was once a seasonal delicacy now is sometimes as cheap as chicken and available year-round. Now, the hidden costs of mass-producing these once-wild fish are coming into focus.

Begun in Norway in the late 1960s, salmon farming has spread rapidly to cold-water inlets around the globe. Ninety-one salmon farms now operate in British Columbian waters. The number is expected to reach 200 or more in the next decade.

Industrial fish farming raises many of the same concerns about chemicals and pollutants that are associated with feedlot cattle and factory chicken farms. So far, however, government scientists worry less about the effects of antibiotics, pesticides and artificial dyes on human health than they do about damage to the marine environment. "They're like floating pig farms," said Daniel Pauly, professor of fisheries at the University of British Columbia in Vancouver. "They consume a tremendous amount of highly concentrated protein pellets and they make a terrific mess."

Fish wastes and uneaten feed smother the sea floor beneath these farms, generating bacteria that consume oxygen vital to shellfish and other bottom-dwelling sea creatures. Disease and parasites, which would normally exist in relatively low levels in fish scattered around the oceans, can run rampant in densely packed fish farms.

Pesticides fed to the fish and toxic copper sulfate used to keep nets free of algae are building up in sea-floor sediments. Antibiotics have created resistant strains of disease that infect both wild and domesticated fish. Clouds of sea lice, incubated by captive fish on farms, swarm wild salmon as they swim past on their migration to the ocean.

Of all the concerns, the biggest turns out to be a problem fish farms were supposed to help alleviate: the depletion of marine life from overfishing. These fish farms contribute to the problem because the captive salmon must be fed. Salmon are carnivores and, unlike vegetarian catfish that are fed grain on farms, they need to eat fish to bulk up fast and remain healthy.

It takes about 2.4 pounds of wild fish to produce one pound of farmed salmon, according to Rosamond L. Naylor, an agricultural economist at Stanford's Center for Environmental Science and Policy. That means grinding up a lot of sardines, anchovies, mackerel, herring and other fish to produce the oil and meal compressed into pellets of salmon chow. "We are not taking strain off wild fisheries. We are adding to it," Naylor said. "This cannot be sustained forever."

In British Columbia, the industry, under pressure from environmentalists, marine scientists and local newspapers, is taking steps to mitigate some of the ecological problems. "We have made some mistakes in the past and we acknowledge them," said Mary Ellen Walling, executive director of the British Columbia Salmon Farmers Assn. "We feel the industry is sustainable, if well-managed, and we have a code of practices that is followed by all of our member companies."

Nearly 30 farms are preparing to move to less ecologically fragile areas, under orders from Canadian authorities. Some farms have installed underwater video cameras to detect when fish quit feeding, so workers can stop scattering food pellets. Many farms are switching to sturdier nets to stop fish from escaping and keep out marauding sea lions, which are shot if they penetrate the perimeter. The industry now recognizes that it will soon be pushing the limits of the ocean.

"There will come a time when our industry will use more of the fish oil and fish meal than is available," said Odd Grydeland, an executive at Heritage Salmon in British Columbia. "Our biggest challenge is to find substitute grains for fish meal and fish oil."

Farm-raised salmon now dominates West Coast markets, arriving daily from Canada and Chile. About 80% of the salmon grown in British Columbia goes to markets from Seattle to Los Angeles. The salmon industry took off so fast in British Columbia in the 1980s that the provincial government, worried about the environmental toll, imposed a ban in 1995 on any new farms. The industry responded by stuffing, on average, twice as many fish into each farm. Today, farms typically put 50,000 to 90,000 fish in a pen 100 feet by 100 feet. A single farm can grow 400,000 fish. Others raise a million or more.

The moratorium on new farms was lifted in September by the provincial government after voters elected a pro-business slate of lawmakers and administrators. As a result, 10 to 15 farms are expected to open each year over the next decade. Five international companies -- three of them based in Norway -- control most of the existing farms. Nearly all are situated around Vancouver Island, which begins outside Seattle's Puget Sound and extends up the coast for 300 miles.

It's a lightly populated place of stunning beauty. Cedar, hemlock and Douglas fir grow right down to the high-water mark. Massive tides flush rich blue-green waters through the archipelago of islands, straits, bays and inlets, nurturing five types of wild salmon. These, in turn, attract seals, sea lions, white-sided dolphins and the world's best known pods of killer whales. Residents rely on boats and seaplanes to reach surrounding islands that host many of the farms. Each farm is a cluster of pens, often interconnected by metal walkways and tethered offshore by a lattice of steel cables, floats and weights.

In the midst of this idyllic setting, signs of strain on the marine environment are bubbling to the surface much the way diseases and parasites, incubated in European salmon farms, fouled the fiords of Norway and the lochs of Scotland. In Norway, parasites have so devastated wild fish that the government poisoned all aquatic life in dozens of rivers and streams in an effort to re-boot the ecological system. "The Norwegian companies are transferring the same operations here that have been used in Europe," said Pauly, the fisheries professor. "So we can infer that every mistake that has been done in Norway and Scotland will be replicated here." Dale Blackburn, vice president of West Coast operations for Norwegian-based Stolt Sea Farm, said his staff works very closely with its counterparts in Norway. But, he said, "It's ridiculous to think we don't learn from our mistakes and transfer technology blindly."

Still, more than a dozen farms in British Columbia have been stricken by infectious hematopoietic necrosis, a virus that attacks the kidneys and spleen of fish. Jeanine Siemens, manager of a Stolt farm, said, "It was really hard for me and the crew" to oversee the killing of 900,000 young salmon last August because of a viral outbreak. "We had a boat pumping dead fish every day," she said. "It took a couple of weeks. But it was the best decision. You are at risk of infecting other farms."

Farms are typically required to bury the dead in landfills to protect wild marine life and the environment. But Grieg Seafood recently got an emergency permit from the Canadian government to dump in the Pacific 900 tons of salmon killed by a toxic algae bloom. The emergency? The weight of the dead fish threatened to sink the entire farm.

About 1 million live Atlantic salmon -- favored by