Ballona Creek Watershed

Ballona Creek Watershed

The Ballona Creek Watershed covers approximately 130 square miles in the coastal plain of the Los Angeles Basin. Its boundaries are the Santa Monica Mountains to the north, the Harbor Freeway (110) to the east, and the Baldwin Hills to the south. The watershed includes the cities of Beverly Hills, West Hollywood, portions of the cities of Los Angeles, Culver City, Inglewood and Santa Monica, unincorporated areas of Los Angeles County, and areas under the jurisdiction of Caltrans. The watershed is highly developed: residential (59%), vacant/open space (17%), and commercial (14%) are the predominant land uses. Overall, 49% of the watershed is covered by roads, rooftops and and other impervious surfaces.

Ballona Creek flows as an open channel for just under 10 miles from mid-Los Angeles (south of Hancock Park) through Culver City, reaching the Pacific Ocean at Playa del Rey (Marina del Rey Harbor). The Estuary portion (from Centinela Avenue to the outlet) is soft bottomed, while the remainder of the creek is lined in concrete. Ballona Creek is fed by a network of underground storm drains, which reaches north into Beverly Hills and West Hollywood. Major tributaries of the Creek and Estuary include Centinela Creek, Sepulveda Channel, and Benedict Canyon Channel. The average dry weather flow at the Watershed’s terminus in Playa del Rey is 25 cubic feet per second – a slow, steady flow. The average wet weather flow is ten times higher, or even more during large storms.

Water Quality in the Ballona Creek Watershed

As of March 2012, the USEPA has approved 22 TMDLs throughout the region that list the City of Los Angeles as a responsible jurisdiction. These include waterbodies within the Los Angeles River, Ballona Creek, Santa Monica Bay, and Dominguez Channel Watersheds.

Ballona Creek and selected tributaries are impaired by pollutants (i.e., trash, metals, bacteria, nutrients) mainly because of the Watershed’s large, dense population and the amount of impervious ground surface that prevents large quantities of runoff from infiltrating into the soils. Currently there are several TMDLs that are in the Watershed, including:

  • Ballona Creek Bacteria TMDL
  • Ballona Creek Metals TMDL
  • Ballona Creek Estuary Toxic Pollutants TMDL
  • Ballona Creek Wetlands Sediment and Exotic Vegetation TMDL

The City with other agencies in the Ballona Creek watershed is currently developing an Enhanced Watershed Management Program (EWMP). The EWMP will identify the measures for compliance with all Ballona Creek TMDLs and other water quality mandates, while maximizing potential benefits of stormwater for local water supply. The draft EWMP will be available by June 2015 and be finalized by April 2016 after review by the Regional Water Quality Control Board.

What is a TMDL?
A Total Maximum Daily Load (TMDL) is the maximum amount of a specific pollutant, such as trash, bacteria, or pesticides that could be discharged into a waterbody without causing it to become impaired. Development of TMDLs, which are driven by the Clean Water Act, are an important step in cleaning up our creeks, lakes, rivers, and beaches.

Related PDF documents available for download

BC Estuary Toxics TMDL Implementation Plan 2011 (7.7mb)
BC EWMP Work Plan 2014 (6.8mb)
Trash TMDL Implementation Strategy and Plan 2006 (4.3mb)
BC Bacteria TMDL Draft Implementation Plan 2009 (8.8mb)
BC Draft CIMP 2014 (9.2mb)
BC Metals TMDL Implementation Plan 2010 (7.1mb)