Storm water from urban runoff is one of the leading causes of pollution in creeks, rivers, and lakes. In fields and forests, most rain water is absorbed by the soil and taken up by plants and trees. However, developed areas contain impermeable surfaces like roofs, parking lots, and streets that cause rainwater and snowmelt to runoff (storm water) and collect pollutants. Storm water that flows from those impermeable surfaces and into storm drains or other conveyance structures without first flowing through best management practices (BMPs), such as grass lined swales or detention basins, goes untreated directly into our creeks, rivers, lakes, deltas and eventually, the ocean.
Storm water is a resource and is ultimately part of the hydrologic cycle, along with our potable water, so it is imperative to keep it as clean as possible. Storm water can become polluted by pesticides, paint, fertilizers, pet waste, litter, oil and other automotive fluids, eroded soil and household chemicals. Even small amounts of pollutants that accumulate on roads, parking lots, and sidewalks can be transported into nearby streams and rivers. Identifying sources of storm water pollution and keeping this pollution away from storm drains and ditches is the best and most economical way to keep storm water clean - which ultimately protects our vital water resources.
Storm water pollution is controlled by the Clean Water Act (CWA) amendments of 1987. The amendments authorized the U.S. Environmental Protection Agency to expand the National Pollutant Discharge Elimination System (NPDES) Program to cover storm water discharges (CWA Section 402). In California, under authority of the Porter-Cologne Water Quality Control Act of 1969, the
State Water Resources Control Board (SWRCB) and the nine Regional Boards beneath it, have the responsibility of managing NPDES Permits under the auspices of the Environmental Protection Agency (EPA).
The NPDES Program is a permitting mechanism that requires the implementation of controls designed to prevent harmful pollutants from being washed by storm water runoff into local water bodies. Ultimately, the SWRCB has complete authority over State water rights and water quality policy.
El Dorado County is covered under two SWRCB Regional Boards. The
West Slope Phase II Municipal Separate Storm Sewer Systems (MS4) NPDES Permit is administered by the
Central Valley Regional Water Quality Control Board (RWQCB) (Region Five). The Lake Tahoe Phase I MS4 NPDES Permit is administered by the
Lahontan RWQCB (Region Six). The current West Slope MS4 NPDES Permit was adopted by the SWRCB on February 5, 2013. The Permit became effective on July 1, 2013 for a term of five years and focuses on the enhancement of surface water quality within high priority urbanized areas. The current
Lake Tahoe MS4 NPDES Permit was adopted and took effect on December 6, 2011 for a term of five years. The Permit incorporated the
Lake Tahoe Total Maximum Daily Load (TMDL) and the
Lake Clarity Crediting Program (LCCP) to account for the reduction of fine sediment particles and nutrients discharged to Lake Tahoe.
On May 19, 2015 the El Dorado County Board of Supervisors formally adopted revisions to Ordinance 4992, Chapter 8.79 - Storm Water Quality Ordinance, which was applicable only to the Lake Tahoe Basin, to include the entire unincorporated portion of the West Slope of the County. Ordinance No. 4992 is now replaced with
Chapter 8.79 - Storm Water Quality Ordinance No. 5022. The Storm Water Quality Ordinance establishes the Legal Authority for the entire unincorporated portion of the County to protect the health, safety, and general welfare of the citizens of the County, enhance and protect the quality of Waters of the State in the County by reducing pollutants in storm water discharges to the maximum extent practicable and controlling non-storm water discharges to the storm drain system, and cause the use of Best Management Practices by the County and its citizens that will reduce the adverse effects of polluted runoff discharges on Waters of the State.
Construction activities include clearing, grading, excavating, stockpiling, and re-constructing new or existing facilities. Construction activity does not include routine operations and maintenance.
When it rains or snows, storm water can carry pollutants from construction sites into storm drains, which convey untreated storm water directly to our creeks, rivers and lakes. Tracked mud and dirt at construction site access points and materials left uncovered, or improperly disposed of can get carried into storm drains.
Use care on construction sites to keep pollution contained at the source. Proper use, storage, and disposal of materials goes a long way toward preventing storm water pollution. It is critical to install
BMPs to help minimize erosion and keep wastes on-site and away from storm drains leading to our waters.
Removing vegetation or disturbing the ground surface between October 15th and May 1st is prohibited in the Tahoe Basin, and for the rest of El Dorado County, additional requirements may apply. To view local erosion and sediment control requirements please visit the
El Dorado County Storm Water Construction Permit Information website.
Specific state regulations extend to construction sites disturbing one acre or more of ground surface or to sites less than one acre in size if they are a part of a larger common development.
For additional state information on construction in Lake Tahoe, visit: Lake Tahoe Construction General Permit
For additional state information on construction on the West Slope, visit: State of California Construction General Permit (West Slope)