New consolidated MS4 permit to manage runoff with flexibility

Stormwater management adapted to each watershed’s land uses, water quality

The Los Angeles Regional Water Quality Control Board (Los Angles Water Board) has adopted a new regional permit to control polluting from stormwater and urban runoff in Los Angeles County, Ventura County, and the City of Long Beach, following four days of hearings that included testimony from the cities and counties subject to the permit, environmental organizations and other interested stakeholders.

The effort to better control bacteria, trash and other pollution that flows from municipal storm drains into surface waters is anticipated to ensure clean water for over 10 million residents and to protect the environment.

Regional rivers, lakes and beaches are significantly impacted by urban and stormwater runoff from one of the most heavily urbanized areas in the country. During lengthening dry periods, inefficient landscape irrigation, construction projects and car washing carry pollutants through the storm drains to surface waters.

Highlights from the 7/28/2021 Media Release appear, below:

  • Under 1990s-era MS4 permits, Los Angeles County, Ventura County and the City of Long Beach were regulated by three separate board orders. This (year’s) action consolidates the permits while reflecting the region’s diverse land uses and water quality characteristics by allowing customized approaches to meet requirements on a watershed basis.

    The permit gives cities and counties the time and flexibility to choose, plan and construct stormwater projects that are appropriate for local conditions and generate other social, economic and water resource benefits such as creation of more parks and green spaces, clean streets, improved wildlife habitat and jobs.

  • Stormwater capture and groundwater infiltration are encouraged as an effective way to improve water quality; the permit increases local water supply resilience to climate change impacts.

The National Pollutant Discharge Elimination System permit for the municipal separate storm sewer system (or “MS4”) covers discharges from 95 cities, Los Angeles County, Ventura County and their two respective flood control districts.

With over 10 million residents, the Los Angeles Water Board regulates the most densely populated region in the state of California, including the coastal watersheds of Los Angeles and Ventura counties and small portions of Kern and Santa Barbara Counties.

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