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For a more specific summary of the most prominent water quality issues facing each California Regional Water Quality Control Board (Regional Water Board), select your region from the following list.

The North Coast Region

The North Coast Regional Water Board covers approximately 10 percent of the State yet yields about 40 percent of the surface water in the State. The region is characterized by numerous rivers and streams of the highest quality, with vast areas of wilderness and managed forests. Most significant point source discharges are well regulated and significant progress has been made with nonpoint sources. In addition to monitoring point sources and working with resource users to enhance beneficial uses, the primary focus is pollution prevention. While a small fraction of the waters have been assessed, these were generally found to be of good or intermediate quality.

In the North Coast Region only a small portion of the total assessed river and stream miles are impaired (about 84 miles). Due to the large number of smaller tributary streams, a large percentage of the total river and stream miles have not been assessed. The economy of the North Coast relies heavily on the timber industry and agriculture. These activities provide jobs, however, they also create changes in the watershed that affect the beneficial uses associated with healthy rivers and streams. Because the area is not densely populated there is a relatively small impact from the sources of impairment that are more common to highly populated areas such as stormdrains and municipal sources.

For more information on the North Coast Regional Water Board, visit www.waterboards.ca.gov/northcoast.

The San Francisco Bay Region

The area encompassed by the San Francisco Bay Regional Water Board is one of the largest urbanized estuaries in the country. Portions of the region also have significant agricultural areas, e.g., the Napa/Sonoma wine region. The rivers and streams of San Francisco Bay Region feed two of California's greatest estuarine assets the San Francisco Bay Estuary and Tomales Bay. Water quality problems result from the diversion of fresh water inflow from the Sacramento/San Joaquin Delta. Other impacts come from the pollutants generated by the six to seven million people living in the region. This includes point and nonpoint, industrial and agricultural, and urban and rural sources of pollutants.

About one quarter of the assessed river and stream miles are considered impaired. More than half the river miles are considered good or are unassessed. The types of water quality problems facing the Regional Water Board are fairly well balanced between those that are typically considered rural (agriculture and mining) and urban (stormdrains, municipal, and land development).

For more information on the San Francisco Bay Regional Water Board, visit www.waterboards.ca.gov/sanfranciscobay.

The Central Coast Region

The Central Coast Regional Water Board includes a rugged seacoast, coastal mountain ranges, wide river valleys of prime agricultural land, a high rainfall redwood forest, and extremely arid inland plains. Many of the rivers and streams of the Central Coast have been harnessed by storage reservoirs for municipal and agricultural purposes. Surface water use has been overextended which has resulted in water quality degradation for aquatic habitat, ground water recharge, and other beneficial uses. Competition for adequate quality water will become more intense in the future.

About one eighth of the total river miles assessed are considered impaired. About the same amount of miles are considered good with the majority of river miles assessed as intermediate or unknown. The types of water quality problems associated with the impaired waters are more weighted toward urban (stormdrains, land development, municipal) than rural (logging, agriculture).

For more information on the Central Coast Regional Water Board, visit www.waterboards.ca.gov/centralcoast.

The Los Angeles Region

The Los Angeles Regional Water Board is characterized by a mix of pristine mountain streams, highly urbanized foothill and valley areas, and heavy residential and industrial coastal areas with highly used recreational beaches and harbors. All of these different land uses present actual or potential threats to water quality from either point or nonpoint sources of pollution.

In 1991, the Regional Water Board assessed 874 miles of rivers and streams, of which, 55 miles (less than 10%) were considered impaired and 464 miles intermediate (threatened). About a third of the river miles are considered good, and a small amount unknown.

Although the Los Angeles region is densely populated with the characteristic water quality problems associated with stormdrains and municipal discharges, there are also rich agricultural lands within the region and these have significant influences on water quality.

For more information on the Los Angeles Regional Water Board, visit www.waterboards.ca.gov/losangeles.

The Central Valley Region

The Central Valley Regional Water Board is the largest of the nine Regional Water Boards, covering about 40 percent of the State. It stretches almost two-thirds the length of California from the Oregon border to the northern tip of Los Angeles County and includes all or part of 38 of the State's 58 counties. Its diversity is exemplified by extensive timber lands, active and abandoned mines, world renowned agricultural productivity from the Sacramento and San Joaquin Valleys and growing metropolitan areas. The main stems of the rivers and streams in the Region have been estimated to be approximately 5,800 miles. Of these, about 5,600 miles have been assessed by the Regional Water Board. Approximately one sixth of the rivers and streams (988 miles) are considered impaired, nearly one third are good, over one third are intermediate and a small fraction are unknown.

Slightly more than half of the impairments are the result of rural activities associated with agriculture and mining. The remaining river miles are impaired by activities that are the result of urbanization including industrial sources, municipal sources and stormdrains.

For more information on the Central Valley Regional Water Board, visit www.waterboards.ca.gov/centralvalley.

The Lahontan Region

The Lahontan Region, larger than the State of Maine, stretches from the State border to the north and San Bernardino to the south and includes hundreds of streams. Many mountain streams have naturally excellent water quality; desert streams provide important aquatic and wildlife habitat. Both stream types historically supported rare fish species and subspecies. Many streams in the Lahontan Region receive heavy recreational use. Two streams are State wild and scenic rivers; many others are under study for federal wild/scenic designation. Very few point source discharges occur; some streams are impaired by water diversions or by nonpoint source problems. Most Lahontan Regional Water Board regulatory activities are related to nonpoint source control, including stream/watershed restoration efforts.

About one third of the river and streams miles are considered impaired and another one third is unknown water quality. Good and intermediate waters make up the remaining third. Water quality problems typical of the region result from using the land for livestock grazing or recreation use (habitat modification). Mining and impairments resulting from agricultural practices are also significant. About a third of the impairment is due to the urban pressures of increased populations (land development, stormdrains, septic tanks, and municipal).

For more information on the Lahontan Regional Water Board, visit www.waterboards.ca.gov/lahontan.

The Colorado River Basin Region

The Colorado River Basin Regional Water Board covers the most arid area of California. Despite its dry climate, the region contains two substantial surface water bodies, the Colorado River and the Salton Sea. The five rivers that flow into and sustain the Salton Sea are, in order of size, Alamo River, New River, Coachella Valley Stormwater Channel, San Felipe Creek, and Salt Creek. The last two are natural, perennial waterways while the first three exist mainly because of their use as conduits for farm runoff flows from the Imperial and Coachella Valleys. Most of the water used to irrigate farmland in this region comes from the Colorado River via canals.

More than half the river and stream miles are considered impaired. This is due primarily to the fact that the Colorado River Basin has limited river miles and many of those are the result of transporting agricultural runoff. Other river miles consist mainly of sewage overflows from south of the border. Good and intermediate waters make up approximately one third of the total river miles.

For more information on the Colorado River Basin Regional Water Board, visit www.waterboards.ca.gov/coloradoriver.

The Santa Ana Region

The Santa Ana Region, although the smallest in the State, is one of the most densely populated. The variety of local water resources is impressive: pristine mountain lakes and streams, lowland reservoirs filled with imported water, inland streams made up of reclaimed wastewater or nuisance water and runoff, critically important coastal wetlands, and the Pacific Ocean, with its broad, sandy beaches. Both the reason for development and the source of the problems has been the large population increase. Of the 448 river miles assessed, 109 miles are impaired by nutrients, pesticides, metals and/or pathogens, originating from agriculture, urban areas, and wastewater discharges. The Regional Water Board is focusing its efforts on preventing further degradation where it exists and developing management strategies to improve the quality of the impaired water bodies.

About a quarter of the total river and stream miles are considered impaired. The majority of the river miles are good with a small amount of intermediate river miles. Water quality impairment resulting from municipal and stormdrain sources make up approximately two-thirds of the impaired river miles and agricultural type impairments make up the remaining third of the impaired river miles.

For more information on the Santa Ana Regional Water Board, visit www.waterboards.ca.gov/santaana.

The San Diego Region

The San Diego Region is characterized by a semi-arid climate, with historically ephemeral inland surface waters. Urbanization of this region, coupled with increasing amounts of imported water is leading to changes in the characteristics of many of the region's streams. Increasing water use is producing an increase in dry weather runoff to the streams. Active management programs need to be designed to maximize the water resource benefits of the increased dry weather runoff, while minimizing all potential detrimental effects.

Only a small percentage of the river and stream miles are considered impaired. The remaining river miles are divided roughly equally into good, intermediate and unknown water quality. The sources of impairment are typically urban (stormdrains and industrial). A small proportion of impairments are considered to be the result of agricultural practices.

For more information on the San Diego Regional Water Board, visit www.waterboards.ca.gov/sandiego.


( Updated 11/17/08 )