The coastal waters of San Diego and Orange Counties are important to the economic vitality of the region, but illness-causing bacteria pose a risk to people who recreate along the coast. The 2010 Total Maximum Daily Load (TMDL) set out to limit bacteria entering the coastal ecosystem from stormwater, but estimated costs are in the billions of dollars.
As part of a triennial review, the Cost-Benefit Analysis (CBA) was launched to provide unbiased and credible information to decision makers as they consider changes to TMDL implementation – with the goal of achieving greater benefits at a lower overall cost. Environmental Incentives and our partner EcoNorthwest used the best available science and economic data to analyze 14 scenarios such as targeting sources of human pathogens (sewers), stream/wetlands restoration, and implementation schedule changes. The project also included a screening-level Financial Capability Assessment that examined the financial burden on rate payers for integrated clean water services, including stormwater compliance and wastewater treatment.
The CBA results showed that addressing high-risk human sources of pathogens is 20x more cost-effective than stormwater improvements for reducing illness at San Diego beaches. Stream restoration was much less cost effective than the other scenarios. The Financial Capability Assessment found that San Diego is solidly in the “high burden” category because clean water costs are nearly double the 2% of median household income threshold. The results are statistically significant and findings are strongly supported by numeric analysis. See the complete findings here, which are being used to better target the implementation plan in a permittee-driven TMDL revision.