Historically Bay Area stormwater programs such as CWP were not charged with monitoring urban runoff. This is because in the past it was believed that the majority of sediment which carries pollutants of concern like Mercury, PCBs, PAHs and PBDEs, reach the San Francisco Bay and Delta Estuary from the Central Valley.
However, recent years of Regional Monitoring Program studies by the San Francisco Estuary Institute have found a larger percentage of pollutant loads than previously expected are coming from stormwater/urban run-off flowing to the Bay from smaller, local watersheds.
For example, ten years ago, a draft of the Mercury Total Maximum Daily Load (TMDL) report summarized existing data, which suggested that 70% of the Mercury entering the Bay came from the Central Valley, with only 20% coming via urban stormwater.
Now the estimate is <40% Mercury coming from the Central Valley, and >40% coming from the urban tributaries.The current estimates of PCB loads suggest that about 30% comes from the Central Valley and 60% enters from urban stormwater runoff.
To further assess what's going on, Section C.8 - Water Quality Monitoring
of the MRP, requires municipalities undertake monitoring for a variety of pollutants in stormwater to get a better a picture of how stormwater contributes pollution to creeks, the Delta, and the Bay.
CWP is working cooperatively through the Contra Costa Clean Water Program and our MRP (and East County) co-Permitees represented by the Bay Area Stormwater Management Agencies Association (BASMAA) Regional Monitoring Coalition (RMC) to undertake various water quality monitoring projects, special studies and pilot programs within waterways in both the San Francisco Bay and Central Valley Waterboard regions.
Here are some of the Pollutants of Concern (POC) monitoring activities CWP is currently engaged in:
- Status and Trends (Regional design commencing in Spring 2012)
- Volunteer Monitoring for Benthic Macroinvertebrates via the Contra Costa Monitoring and Assessment Program (CCMAP) find out more at: Volunteer Monitoring Program
- Regional Monitoring Program (Bay Area)
- C.11 Mercury & C.12 PCB by Clean Watersheds for a Clean Bay (CW4CB)
- POC & Long Term Monitoring (commencing in Fall 2011)
For Permit Year 2011/12, the Clean Water Program on behalf of the CWP and our Contra Costa co-Permittees is budgeted to spend over $700,000 in monitoring programs and projects required under Sections C.8 (Water Quality Monitoring), C.11 (Mercury), C.12 (PCBs) and C.13 (Copper).