Low Impact Development Monitoring and Assessment, Lessons Learned and a Path Forward
As Low Impact Development (LID) continues to be the focus of stormwater permits and has be increasing implemented over the past 10 years in California an understanding of the effectiveness of the LID BMPs is needed. The current understanding of the true effectiveness of LID BMPs in California however is lacking. Based on a recent experience and a recent survey of local jurisdictions in California, few LID BMPs are being regularly inspected and even fewer have monitoring or evaluation requirements. Monitoring is conducted primarily at grant-funded public demonstration and research sites. Even within these case sites, current monitoring methods and objectives are not consistent. The result is a lack of data regarding LID effectiveness in California. A consistent approach for monitoring LID in California is needed to understand the effectiveness and benefits of LID, which can then help to modify design and implementation of LID as well as understand the overall watershed effects through implementation of LID.
The presentation will explore lessons learned from recent monitoring of LID measures as well as describe the current efforts in California to monitor LID. The presentation will also describe a comprehensive effort to identify the key elements for a consistent approach to monitoring and determining the effectiveness of LID BMPs for pollutants of concern and for reduction in hydromodification impacts in California. The effort to have a comprehensive understanding of LID monitoring efforts in California through coordination with agencies and organizations which are working to monitor and understand the performance of LID BMPs will also be described. The presentation will also explore an initial approach to identifying answering key questions regarding LID BMPs including evaluation of relevant LID BMP monitoring work, compilation of existing LID BMP performance data and information, characterization and quantification of water quality benefits, evaluation of LID BMP performance over time, evaluation of the role of maintenance of LID BMPs in performance and monitoring, evaluation of LID BMP designs for inclusion of monitoring and maintenance features, and determination of what data to collect that will most effectively improve LID BMP performance over time. This approach will help to guide future design, implementation, and monitoring of LID including the adequate collection of data to have a more comprehensive understanding of LID in California and its true benefits.