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PAPERBACK price:$48.75 add to cart Rights & Permissions Free PDF Access Sign in to download PDF book and chapters Free Resources Display this book on your site! Related Titles Managing Troubled Waters:The Role of Marine Environmental Monitoring Managing Wastewater in Coastal Urban Areas Other Related Titles Monitoring Southern California's Coastal Waters (1990) Commission on Engineering and Technical Systems (CETS) Citation Manager Export the bibliographic data for this book in your chosen format Web Search Builder Use this book's key terms to search within this book, across our collection, or across the Web. Skim This Chapter Skim this chapter and use this chapter's key terms to search within this book. Reference Finder Paste in your own text to find books that relate to your topic. Citation Manager . "1 The Southern California Bight." Monitoring Southern California's Coastal Waters. Washington, DC: The National Academies Press, 1990. Please select a format: Page 1   E-mail Share on facebook Facebook Share on delicious Delicious Share on stumbleupon Stumble Share on twitter Twitter More Sharing ServicesMore Page 1 Front Matter (R1-R14) 1 The Southern California Bight (1-15) 2 Sources of Pollution and Habitat Change (16-41) 3 Regulatory Framework and Public Concerns (42-53) 4 Monitoring and Research in the Southern California Bight (54-96) 5 A Framework for the Analysis of Monitoring (97-115) 6 Analysis of Monitoring Efforts (116-141) 7 Conclusions and Recommendations (142-144) References (145-154)

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The Southern California Bight No system of marine monitoring exists in the abstract. Monitoring occurs in specific geographic regions that have particular qualities derived from their natural characteristics and processes. The marine environment in turn is affected by the human activities that take place in and adjacent to it. Understanding the strengths and weaknesses of monitoring in the Southern California Bight therefore requires a basic knowledge of the physical setting and human activity within it. This chapter describes the physical setting of the Southern California Bight: its bathymetry, drainage basin, circulation and ocean-ography, cli- mate, and hydrology. It also describes the natural habitats and resources of the region and the land use and economic activities of the adjacent coastal areas. Chapter 2 will describe in greater detail the sources and types of habitat change and pollutant loadings to the marine environment that stem from human activities in the bight. PHYSICAL SETTING The Southern California Bight is bounded on the north, east, and southeast by a long cume of the North American coastline extending from Point Conception in Santa Barbara County, southeast 357 mi to Cabo Colnett, Baja California in Mexico (Figure 1-1~. It is bounded to the west by the California Current, which flows southeasterly approximately parallel to the coast and the edge of the continental shelf. The bight system includes

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2 more than 37,000 mi2 of ocean and approximately 8,700 mi2 of adjacent coastal areas draining into it. Bathymetry The bathymetry underlying the Southern California Bight has many features unique to the continental shelf surrounding the United States. For this reason the area was named "continental borderland" by Shepard and Emery (1941~. Topographic features in the continental borderland and adjacent mainland drainage basin are summarized in Bible 1-1. The waters of the bight overlay an alternating series of 2,000- to 8,000- ft-deep basins and surfacing mountains that form 9 offshore islands or island groups and several large submerged banks and seamounts. Nearshore, 12 large submarine canyons influence movement of sediments and other materials deposited on the bottom. There are also 32 submarine canyons on the continental slope bordering the U.S. portion of the bight, including 20 canyons that cut into the mainland shelf (Emery, 1960~. Offshore, there are 18 marine basins, 3 of which are essentially anoxic. These submarine canyons and deep basins are important sites of accu- mulation of fine-grained sediments and particulate materials from land runoff, ocean discharges, and ocean dumping. An important feature throughout the bight is that deep water is close to shore. All slopes are steep, ranging from 5 to 15 percent. Island and mainland shelves are narrow, from less than 0.6-mi wide to a maximum of 12.5-mi wide. The mainland and island shelves constitute only about 11 percent of continental borderland area; marine basins cover about 80 percent of the borderland area. The most important embayments of the mainland shelf are Santa Mon- ica Bay and San Pedro Bay (separated from each other by the prominent and steeply sloping Palos Verdes Peninsula and shelf), San Diego Bay, and Todos Santos Bay in Baja California. Although no true estuaries penetrate the mainland coast, there are at least 26 wetland systems in coastal lagoons and at the mouths of transient streams and rivers in the U.S. portion of the bight (Figure 1-2~(Zedler, 1984~. The total area of these coastal wetlands is only about 129 mi2, an estimated 25 percent of the area they encompassed when the first Europeans arrived in Southern California in the late 1500s. Drainage Basin The onshore mainland drainage basin of the Southern California Bight, occupied by an ever-increasing human population of nearly 15 million, is a triangle-shaped, higher elevation extension of the offshore bathymetry. It consists of nearly equal areas of mountains and basins or plains (Table

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3 Point Conception 119° 118° 117° 116° At'. I `~` Barbar~?~ ~ Hueneme Canyon , ~aMGUEL ~ p I LOS ANGELES SANTA Santa Redon . ~ ROSA I. ~ Monica ~\ Canyon ~ ~\S~p~ 1~'': 34o ho 32O 31° _ 3oo f i ~ /~ ~ _ 2000 ~ ~ t ~ 2000 I ~ I 1 1 ~ 120 119 118° \ 2000 l _ 33o _ 32O 31° : 1000 ~Uintin 117° 116° 300 FIGURE 1-1 Bathymetry of the Southern California Bight, emphasizing its deep basins (shaded). Depth contours are shown in fathoms (1 fathom = 6 ft). SOURCE: Moore, 1969. 1-1). The rising shoreline is characterized by vertical scarps and wave-cut cliffs. There are as many as 20 raised marine terraces on land that are an extension of the 5 submerged terraces that lie at depths to 289 ft along the mainland shelf (Emery, 1960~. The drainage basin is bordered on the north by transverse (east-west ranges extending from Point Conception eastward along the Santa Monica,

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4 TABLE 1-1 Topography and Bathymetry of the Southem California Bight Area Area Area Feature Mi2 % Total % Borderland Mainland mountains4,600 10.0 -- basins and plains4,090 9.0 -- Subtotals_8,690 19.0 -- Borderland islands340 0.7 1.1 mainland shelf1,890 4.1 6.2 island shelves1,390 3.0 4.6 bank tops2,420 5.3 8.0 basin and trough slopes19,120 42.0 63.3 basin and trough floors5,120 11.2 16.8 Continental slope1,960 4.3 -- Abyssal seafloor4,740 10.4 -- Subtotals36,980 81.0 -- Totals45,670 100.0 100.0 SOURCE: Emery, 1960. San Gabriel, and San Bernardino mountains; and on the east by coastal ranges that continue southward down the length of the Baja Peninsula (SCCWRP, 1973~. These mountain ranges separate the semiarid coastal plain from the very arid desert basins. Because of the semiarid nature of the drainage basin and the highly seasonal pattern of annual precipitation, most of the rivers draining into the bight are small and are dry for much of the year. From north to south, the major rivers in the drainage basin are the Santa Clara, Los Angeles, San Gabriel, Santa Ana, San Luis Rey, San Diego, and Tijuana rivers (Figure 1-2~. Much of the length of the Los Angeles and San Gabriel river beds and other major drainages are now lined with concrete. Most rivers have dams and debris basins constructed upstream to aid in flood control. In Southern California, there are separate systems to handle stormwater runoff and municipal wastewater flows. Circulation and Oceanography The western border of the Southern California Bight is marked by the California Current, which flows southeastward along the coast, continuing the clockwise geostrophic transport of water in the North Pacific Ocean (Figure 1-3~. Water current regimes in the Southern California Bight are

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s ETA CLARA RIVER -4_~1-~ ~ LOSANGELES RIVER ~ ~ , ~ ~ ~ ~ ~ ~ ~ f l SAN GABRIEL RIVER POINT CX~ ~ ~ ~ j ) ~ MA MARGARITA C t PALOSVERDES~LUIS REY RIVER ~)~P~ lo go 30 do ~Bo SCALE IN ALES p 4 <~, '/C o 1. TIJUANA ESTUARY 2. SWEETWATER MARSH, PARADISE CREEK MARSH, E,f &~.MARSHES, SOUTH SAN DIEGO BAY WETLANDS 3. MISSION BAY MARSH IKENDALL FROST RESERVEI. FAMOSA SLOUGH AND CHANNEL SAN DIEGO RIVER MARSH 4. LOS PENASQUITOS LAGOON 5. SAN DIEGUITO LAGOON 6. SAN ELIJO LAGOON 7. BATIQUlTOS LAGOON B. AGUA H EDIONDA LAGOON 9. BUENA V ISTA LAGOON 10, SAN LUIS REY RIVER MARSH 11. SANTA MARGARITA RIVER 12, LAS FLORES MARSH 13. SAN MATED MARSH 14. UPPE R NEWPORT BAY 15. BOLSA CHICA BAY 16. ANAHEIM BAY, HUNTINGTON BEACH MARSH, SANTA ANA RIVER MARSH 17 ALAMITOS BAY (LOS CERRITOS MARSH) 18, BALLONA WETLANDS 1DEL REY LAGOONI, BALLONA LAGOON, AND BALLONA MARSH 19, MALIBU CREEK 20. MUGU LAGOON 21 McGRATH LAKE 22. SANTA CLARA RIVER 23. V ENTU RA R IVE R 24. CARPINTERIA MARSH 25. GOLETA SLOUGH 2e. DEVERAUX LAGOON SAN DIEGO RIVER OR VeR MEXICO FIGURE 1-2 Location of Southern California coastal wetlands and major nvers. SOURCE: Zedler, 1984. complex and variable on seasonal and longer time scales. Only the general patterns will be described here. Because of the eastward indentation of the coast in the Southern California Bight, a surface counterclockwise gyre, the Southern California Eddy, breaks off the California Current and carries water northward through the central bight (Jones, 1971; Hickey, 1979~. The eddy is usually well developed in summer and autumn and weak in winter and spring. Closer to the shore along the mainland shelf, prevailing onshore (north- westerly) winds reverse this flow, resulting in a net aIongshore surface flow toward the southeast at speeds of 1 to 3.3 cm/s (Lentz and Winant, 1979~. Hendricks (1977) reported that the mean direction and velocity of water currents just below the thermocline are upcoast at 3 cm/s, and that this near-bottom current has a significant offshore component. Coastal currents reach maximum velocity in water depths of about 197 ft (Jackson, 1986~. These complex nearshore currents are interrupted by coastal headlands and upwelling epicenters and respond to both regional and local land-sea breezes. During the afternoon, sea breezes are responsible for both cool- ing on land and shoreward movement of natural and man-made floating materials. There is also a very nearshore circulation pattern caused by surf along

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Santa Barbara i,. 15° C-: j ~ ~: ~San Diego 5 Prevailing Winds ~ Surface Water Flow _ Mid-depth Water Flow Below 660 ft (230 m) OCR for page 7
7 the periodic climatic anomalies known as "E1 Nino" events (described in detail later in this chapter). There is still some uncertainty about the continuity between the Davidson Current and the deep countercurrent in the bight (Hickey, 1979~. Because surface waters in the bight originate primarily from the south- flow~ng California Current, they are more nutrient-rich, less saline, and cooler (annual range 13° to 20°C) and undergo less seasonal temperature variation than nearshore surface waters at similar latitudes along the east coast (e.g., South Carolina and Georgia). Temperature drops with increas- ing water depth to about 4° C in the basins. Dissolved oxygen concentration also tends to decrease with depth, such that waters below the sill depths of the Santa Barbara, Santa Monica, and San Pedro basins are periodically or permanently anoxic (Emery, 1960~. Due to anoxic conditions, bottom water and sediments in these basins are virtually devoid of higher life forms. The basins are major repositories for sediments and other particulate materials (including sludge) transported onto the shelf from the land and coastal waters. Climate and Hydrology The climate of Southern California is like that of the Mediterranean, with most of the precipitation occurring during winter months. Monthly mean temperature and precipitation for Los Angeles and San Diego are summarized in Able 1-2. Monthly mean temperatures in both cities vary by only about 10°C, though periodic extreme temperatures may range over about 35°C. Mean monthly precipitation ranges from near zero in June, July, and August to 2.0-3.3 in. (50 to 85 mm) in December, January, and February. It is now clear that many environmental changes in the bight are connected more with long-term, low-frequency, interannual patterns than with seasonal Cycles. Displacement of cool surface waters including their inhabitants-in the bight by clear, nutrient-poor warm water is correlated with periodic warm-water events off the coast of Peru and in the tropical Pacific. These are the El Nino events, which occur several times per decade (e.g., 1976, 1979, 1982-1984, 1986-1987) and are characterized by warm wa- ter, a deeper surface-mixed layer, elevated sea levels, increased abundance of southern planktonic and pelagic organisms, alterations of benthic com- munity structure, and degeneration of coastal kelp beds (Jackson, 1986~. E1 Nino events and other long-term oceanographic changes also affect the weather in the bight. In some years (e.g., 1969 and 1982-1983) floods rule the coastal plain; in other years drought occurs (e.g., 1976-1977~. In some years, there is a deep-penetrating, southerly ocean swell that mixes and resuspends mainland shelf sediments.

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8 a ~ ~0\ ~ ~ -~ Cal Cal Cal ~Cal Cal 0 __ e . lo 0 . C) C) U. .s - .~ . PA I} PI Ed o ~5 - Cal i_ o . - C) C. PI % O ~ - 00 Cal Cal Cal X of _ _ ~00 _ _ of en m 00 __ = - e' _ _ on mm O __ CD Cot C) 0 ~ 0 S . ~ . 6 ~< o ~o Cat ~fi ~. ~C) Go to . . C) to Cat

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9 Crustal blocks between numerous faults move with alarming frequent y, causing earthquakes. Oil and tar continuously ooze from shelf and island seeps, periodically creating large marine oil slicks. During some droughts, brush fires, fed by northeasterly Santa Ana winds, spew plumes of ash and soot onto the adjacent sea and coastal plain Landslides and subsidence are common and predictable in certain hill and bluff areas. In short, the predominantly mild sunny climate of the Southern California Bight area does not reflect the major impacts of occasional meteorological and geological events. Fresh water enters the bight from a variety of sources. Riverine runoff from rain and melting snow is very seasonal. Much of the water imported from Northern California through the California Aqueduct, from the high Sierra Mountains through the Owens Valley Aqueduct, and from the Col- orado River through the Metropolitan Aqueduct (%ble 1-3) eventually finds its way to the bight through land and subterranean runoff and dis- charges of waste water. The cost of wastewater disposal from municipal and industrial activities is 5 to 10 times the cost of supplying the water (World Bank, 1980~. Disposal costs for agricultural drainage are about half those of water supply, unless treatment is required. Because of the semiarid climate of the bight drainage basin, the vol- umes of water entering the bight from wastewater discharges are compara- ble to those from riverine and storm drain inputs. Because stormwater flow is more variable than wastewater flow, in dry seasons and years wastewa- ter flow far exceeds that of storm water. For example, the mean treated wastewater flow to Santa Monica Bay between 1967 and 1982 was 346 million gal/day, with the annual mean increasing from 320 million in 1967 to 379 million gal/day in 1982 (Gerber, 1987~. Stormwater flow to Santa Monica Bay over the same period averaged 143 million gal/day and ranged from 51 million gal/day in 1972 to 400 million gaVday in 1969. However, nearly all of this stormwater flow occurred during and shortly after a few winter storms each year. Thus, the only continuous freshwater flow to the bight is treated municipal waste water. This includes primary, secondary, and tertiary treated sewage discharged directly to the ocean from coastal treatment plants and tertiary treated sewage discharged from inland treat- ment plants to Southern California rivers and streams. This pattern of freshwater input to coastal waters is quite different from that in much of the rest of the coastal United States, where riverine and stormwater flow far exceeds wastewater flow. HABITATS AND NATURAL RESOURCES Natural habitats and resources characteristic of the Southern Califor- nia Bight include abundant deep water close to shore, extensive coastal

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10 TABLE 1-3 Water Supply and Demand in Southem California Parameter19902010 Estimated population (millions)&15.2917.75 Water suWly (millions of gal/day) local1,9551,955 reclaimed143152 Los Angeles Aqueduct375375 Colorado River714420 state water project ~1~295 Total supply4,3304,147 Water utilization (millions of gal/day) residential1,6a72,090 commercial473643 industrial330411 publics4114M agricultural794580 Total demand3,6154,188 Supply minus demand+ 715- 41 Per capita demand (gallday) residential1051 18 commercial3136 industrial2223 publics2726 agriculture5230 Total per capita demand237233 California Department of Finance data, assuming half of total increases in county projections will occur in coastal drainage area. bIncludes unaccounted for water. SOURCE: Califomia Department of Water Resources, 1987; Los Angeles Department of Water and Power, 1985-1986 Annual Report; State Water Contractors, Bay-Delta Hearings, June 1987, SWC Exhibit Numbers 3, 6, 13, 17, 76. and offshore oil reserves, commercially or recreationally valuable fish and shellfish stocks, wildlife breeding and overwintering areas, kelp beds, beach and water recreation areas, and a climate tempered by the special oceano- graphic processes reviewed above. As a result of the local oceanographic regime, particularly the Southern California Eddy, the bight is an enclave of communities of marine life specific to the area, except during E1 Nino years. It is also a trap for warm water and natural and anthropogenic materials entering the area from land, sea, and air. Six species of seals and sea lions and the northernmost Pacific popula- tion of pelicans breed on several islands. Regional populations of porpoises

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11 occur in the bight, and the entire population of gray whales spends a por- tion of fall and winter there during its annual migration between the Bering Sea and Baja California. Commercially exploitable stocks of anchovies, sardines, and mackerel spawn and grow primarily in the bight, as do bass, croakers, Catfishes, and rockfishes. Mariculture operations have been established in Agua Hedionda Lagoon in San Diego County (mussels and oysters) and in the Santa Barbara Channel (oysters, mussels, and scallops) (California Department of Health Services, 198Sb). Deeper waters of the bight host a diversity of mesopelagic fishes that spend part of their life Cycle in surface waters. The benthic fauna of the continental shelf, especially polychaetes and crustaceans, are very diverse and constitute an important food source for many fish species. Rocly intertidal and subtidal areas, which cover large areas of the shoreline of the bight, host a rich diversity of epifauna (snails, mussels, crabs, etc.) and attached seaweeds. Beds of the giant kelp Macrogystis pyrifera, which attach to the bottom and can grow to over 164 It in length, extend along the coast of the bight. There are 33 locations in the bight between Point Conception and San Diego where kelp beds are found at least periodically at water depths ranging from 20 to 65 ft. From the 1930s lo 1979, individual kelp beds occupied up to 2,720 acres, with the total area occupied by kelp beds in the range of 12,000 to 15,000 acres (Foster and Schiel, 1985~. The size and distribution of kelp beds varies spatially and temporally in response to changes in natural and anthropogenic conditions. Natural changes in surface water temperature and nutrient concentrations associated with El Nino events, and.possibly with longer-term ocean warm- ing trends, have resulted in declining kelp beds in some areas, and winter storms like those of 1983 and 1987 can devastate large kelp beds. These storms probably are the most important factor influencing the condition and areal extent of kelp beds, but human activities such as kelp harvests, boat traffic, and possibly wastewater discharges at Palos Verdes and Point Loma have also affected local giant kelp beds. LAND USE AND ECONOMIC ACTIVITY A combined U.S.-Mexico population of about 15 million people lives in, works in, and enjoys the coastal climate and resources in the drainage basin of the Southern California Bighte The population in this area has increased steadily since the 1890s. Although once primarily an agricultural region, Los Angeles and ad- joining counties now comprise the manufacturing, petrochemical, commer- cial, and aerospace center of western North America. There also are large military bases throughout the area. Accessible land space is now largely

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12 occupied by several hundred cities, hundreds of square miles of residential areas, highways, airports, and citrus groves. Because of current land and water use practices, the entire region is heavily dependent on water diverted from northern and eastern California and the Colorado River system Cable 1-3) that would otherwise flow into the San Francisco Bay and delta area, Mono Lake, the Owens Valley east of the Sierra Mountains, and the Gulf of California. Water utilization in Southern California is projected to increase in the next 22 years due to an expected 16 percent increase in population, and despite a projected slight decrease in per capita consumption of water Cable 1-34. However, at the same time, total freshwater supply will decrease due to partial loss of water rights to the Colorado River. Disputes over other water sources continue, and these supplies are by no means assured for future use by Southern California. As a result, demand will be greater than supply by the year 2010, requiring increased conservation and on-site reclamation. As described in "Climate and Hydrology," the base flow for most of the Southern California drainage system is now derived from treated waste water (see Chapter 2, Figure 2-2 for further detail). Secondary or tertiary treated sewage from inland treatment plants makes up much of the permanent flow of the Los Angeles, San Gabriel, Rio Hondo, and Santa Clara rivers in Los Angeles and Ventura counties. These discharges, as well as other NPDES-permitted (National Pollutant Discharge Elimination System) flows to the rivers are strictly regulated to protect water-contact recreational areas. However, storm drains and nonpoint source runoff to rivers are not regulated. Such flows may contain elevated concentrations of chemical contaminants and pathogens. Highways are the principal basis of transportation in Southern Califor- nia. Heavy manufacturing (metals, chemicals) is located near the coast and within convenient access to well-developed port facilities in Los Angeles, Long Beach, and San Diego harbors. The most active shipping, shipbuild- ing, and maintenance in western North America occurs in the combined complex of Los Angeles-Long Beach harbors; and military activities oc- cur around Mugu Lagoon and Anaheim Bay (munitions), along the north San Diego County coastline (Camp Pendleton Marine Base), and at San Clemente Island (target practice). The harbors of Long Beach and San Diego were principal Pacific staging areas during World War II (1941-1945) and continue today as active naval and ship building bases. Oil extraction has occurred for eight decades within and onshore of coastal city limits of Goleta, Carpinteria, Ventura, Oxnard, Santa Monica, Redondo Beach, Wilmington, San Pedro, Long Beach, Seal Beach, and Huntington Beach. Terminal Island and adjoining areas sank up to 30 ft (Allen, 1973) when oil was pumped out in the 1930s and 1940s. Offshore oil extraction from shore-based facilities began near the turn of the century

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13 along the Santa Barbara Channel and slightly later in southern Los Angeles and Orange counties. Oil production from offshore platforms began 35 years ago on nearby shelves (1 to 3 mi from shore) and now extends nearly to the shelf break. Proposals for more extensive offshore oil exploration and development in the bight are being hotly debated because many Southern Californians consider them a great potential pollution hazard to the marine environment. An extensive shore-based infrastructure has sprung up to support offshore oil production activities including pipelines, refineries, produced water treatment facilities, and oil terminals. Year-round commerce, fisheries, and marine recreation, combined with steady population growth, have resulted in constant development of har- bors, marinas, and coastal home sites in Southern and Baja California. The region's 30,000 to 40,000 pleasure boats are concentrated primarily in Marina del Rey on Santa Monica Bay, in the new Los Angeles City Cabrillo Marina, in Alamitos Bay, Long Beach Marina, Huntington Har- bor, Balboa-Newport harbors, northern San Diego Bay, and Mission Bay; and secondarily in marinas at Oceanside and Dana Point, and in Ox- nard, Ventura, and Santa Barbara. Because pleasure boats are sources of fuel leaks and toxins from antifouling paints, they constitute a potential environmental problem that has not yet been quantified. Fourteen coastal electric power plants in Southern and Baja California supply much of the region's power and recirculate nearly 11 billion gaVday of nearshore seawater, some of which controls circulation in harbors and marinas. Most generating plants operate on oil delivered by offshore tankers, and of! spills occasionally result from accidents involving tankers supplying fuel to plants in Southern and Baja California (e.g., Nishikawa- Kinomura et al., 1988~. For example, in Los Angeles/Long Beach harbors where most of the tanker terminals are concentrated, an estimated 1.3 million gal of oil and fuels have been spilled since 1976; in the Santa Barbara Channel, since 1969 over 3.5 million gal of oil have been spilled from two oil platforms and a tanker collision. The San Onofre Nuclear Generating Station (SONGS) is the only nuclear plant on the coast of the bight. Much of the region's 1.5 billion gaVday of raw sewage is collected via large-scale intercity networks of trunklines and transferred to 13 coastal Publicly Owned Treatment Works (POTWs) where effluent is subjected to primary, advanced primary, and in some cases secondary treatment and discharged to the ocean via submarine outfall diffusers at depths from 65 to 328 ft. Tertiary treatment currently reclaims almost 150 million gaVday of water, and there is a future potential to reclaim 0.5 billion gaVday. The reclaimed water is used for landscape irrigation, groundwater recharge, industrial processing, and control of saltwater intrusion into coastal aquifers. Storm water is completely separated from sewage in all

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14 major systems, but overflows occasionally occur. However, as discussed above, several POTWs discharge secondary or tertiary effluent to Southern California rivers for transport to the ocean. For example, the Los Angeles and San Gabriel rivers each receive about 100 million gaVday of treated waste water. Percolation of storm water into aging sewer lines during storms occasionally overwhelms the system, resulting in release of raw sewage to the bight. The least developed areas of the bight include the northwesternmost 37-mi stretch of coast between Point Conception and Santa Barbara, the 12-mi coastline of Camp Pendleton in northern San Diego County, the central San Diego County coastline, the Channel Islands, and the Baja California coast south of Ados Santos Bay, near Ensenada. In summary, there is little coastal space that has not been subject to construction, mineral extraction, or other forms of resource utilization. There is keen competition for coastal space, access, and resource utilization and, as a consequence, conflict among the many potential users. The California Coastal Commission, formed as a result of a 1969 ballot initiative, resolves conflicts related to multiple uses of the coastal zone. SUMMARY There are several natural and anthropogenic features of the Southern California Bight that are important for the consideration of environmental impacts and marine monitoring in the bight. The continental shelf through- out the bight is very narrow, and deep water exists near shore as a result of the bight's many submarine canyons and basins. The bight's western border is defined by the California Current, and the complex pattern of currents, eddies, and counter currents creates enclaves of indigenous bio- logical communities. Many important environmental processes and changes are related more to long-term, low-frequency, interannual patterns than to yearly or seasonal cycles. The semiarid drainage basin of the bight receives sparse rainfall and much of the human activity in the area depends on imported water. As a consequence, many area rivers are dry much of the year, and wastewater flows constitute the only continuous freshwater input to the bight. Wastewater flows from treatment plants exceed natural flows from runoff and storms. Because waste water and storm water are man- aged by separate systems, however, the bight does not have the combined sewer overflow problems that characterize other coastal areas in the United States. The Southern California Bight contains rich biological resources that support diverse commercial and recreational activities. In addition, many marine mammal species, including the entire gray whale population, spend part or all of each year in the bight.

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15 Finally, as a result of Southern California's large population and attendant intense economic and recreational activity, there is little coastal space that has not been subject to construction, mineral extraction, or other forms of resource utilization. This activity has resulted in extensive habitat change and lame and wried inputs of contaminant to the bight. louse are reviewed in the next chapter.

Representative terms from entire chapter:

drainage basin