San Diego Bay contributes greatly to our local economy by helping to sustain our maritime and recreational industries, and also providing a home to marine mammals, green sea turtles (Chelonia mydas) and over 600 species of fish, birds and invertebrates—many of which are rare or endangered. The San Diego Bay watershed is comprised of three hydrologic units (Pueblo, Sweetwater and Otay) that encompass an area of over 282,000 acres. The watershed is home to some of the more extensive and intensive urban development in the San Diego Region. The watershed also houses the most diverse population in the region and it is estimated that 934,550 reside within its boundaries. Urban development in the watershed has resulted in channelization, floodplain encroachment and the loss of associated wetland habitats. Much of the pollution in the San Diego Bay watershed and its receiving waters is attributed to non-point sources, which reach the waterways via the storm drain conveyance system. According to a 1996 National Oceanic and Atmospheric Administration (NOAA) study, San Diego Bay ranked as the nation’s second most toxic of 18 bays studied throughout the nation.
The San Diego Coastkeeper’s BWQMP is working closely with regional agencies to identify and abate major sources of water pollution into the bay to protect the biotic integrity of this important habitat. Since 2001 the San Diego Coastkeeper has been involved in implementing monitoring efforts in the Chollas and Paleta creeks, which comprise two of five toxic hotspots in the Bay. Chollas Creek is a CWA 303(d) impaired waterbody and its mouth a moderate priority Toxic Hot Spot (BPTCP 1996) due to the presence of high levels of pesticides, metals, and toxicity. Stormwater samples from Chollas Creek have frequently exceeded both chronic and acute water quality criteria established in the California Toxics Rule (CTR) (40 CFR Part 131) for copper, lead, and zinc. Also, this waterbody has not met the RWQCB Basin Plan toxicity objectives for almost all tests performed since 1994 (URS Greiner Woodward Clyde 1994-1999). In addition, just south of Chollas Creek is Paleta Creek that drains into the 7th Street Channel, a high priority Toxic Hot Spot (BPTCP 1996) also on the CWA 303(d) list. Paleta Creek and 7th Street Channel receive industrial, commercial and municipal discharges and continue to be impacted by urban stormwater runoff. Water samples from Paleta Creek indicate the presence of high levels of dissolved metals and coliform bacteria while sediment samples from 7th Street Channel show elevated levels of dissolved metals and pesticides (DDT). Furthermore, during rain periods, pollutants from these creeks flow directly into San Diego Bay resulting in a visually distinct plume of contaminants (SCCWRP 2001). These contaminants affect sensitive habitat, harm biodiversity and pose a latent risk to public health. Already, 14 acres of San Diego Bay adjacent to the mouth of Chollas Creek have been 303(d) listed for having impaired benthic communities and elevated sediment toxicity. To address some of these problems, the San Diego Regional Water Quality Control Board (SDRWQCB) is currently implementing Diazinon and Dissolved Metals Pollution Control Plans (known as Total Maximum Daily Loads or TMDLs). The San Diego Coastkeeper is working with government agencies to track pollution levels and evaluate the performance of these pollution management plans, develop environmental information resources for San Diego Bay and evaluate the effectiveness of new pesticide and organic chemicals monitoring technologies.
Current Projects in San Diego Bay:
Monitoring Sites:
Monitoring Frequency: Monthly and quarterly
Type of Effort:Volunteer and applied research water quality monitoring
Parameters: Water temperature, dissolved oxygen, pH, turbidity, conductivity/salinity, nitrate-nitrite, indicator bacteria, dissolved metals and organophosphate-pesticides and field observations.