The municipal stormwater management permit issued for north Orange County requires a new level of stormwater management. New land development and significant redevelopment projects must incorporate Low Impact Development (LID) practices to infiltrate, harvest and reuse, evapotranspire, or biotreat stormwater on site to the maximum extent practicable. It is anticipated that many development projects will determine that on-site infiltration is the most effective approach to comply with the permit. In some cases, regional LID practices may be more appropriate than on-site LID. The MS4 permit and emphasis on on-site LID raises new questions about long-term impacts on groundwater resources from installation of many small-scale infiltration facilities. Specifically, how will implementation of the MS4 permit affect the Orange County Groundwater Basin, a vital source of drinking water in a highly urbanized environment? Also, what are the advantages and disadvantages of on-site versus regional LID?
This presentation will examine technical issues and policy questions, such as:
- What should be done to monitor the potential impacts of small-scale infiltration facilities?
- What conditions favor the implementation of regional compared to on-site LID?
- Is there an approach to regional LID that addresses the regulators’ policy goal of managing stormwater as close as possible to the source?
- What are the regulatory barriers to regional LID and how can they be addressed?
- What technical studies are needed to address these issues?
