Novel Techniques for Successful Storm Water Treatment BMP Effectiveness Monitoring
Storm water regulations have progressively evolved from characterizing receiving water conditions and outfall runoff to include BMP implementation and effectiveness studies. As a result, storm water treatment BMPs are becoming more systematically integrated into MS4 Permits and monitoring practices. Some BMPs are designed to reduce targeted contaminants, others are designed to reduce aggregate flows, or both; but the overall goal remains the same – reduce pollutant transport affecting beneficial uses in downstream receiving waters. How effective are these BMPs? The quality of flow data alone can contribute significantly to the reported range of BMP effectiveness. While general guidance on traditional storm water monitoring practices is widely available, BMPs often introduce new technical challenges that inhibit data quality and resolution. Further, using a traditional flow monitoring approach to obtain defensible flow data can be challenging and/or impossible where hydraulics are complex.
Although not directly building bridges for water, storm water treatment BMPs implemented by Caltrans throughout California are storing and treating water between bridges, along highway shoulders, medians, and on/off ramps. This presentation will stress the importance of data quality in challenging environments, using the Caltrans District 11 Chollas Creek Diazinon and Dissolved Metals TMDL Implementation Monitoring Program as a case study. District 11 has implemented several types of storm water treatment BMPs, including biofiltration swales and modular infiltration trenches, and monitors their performance annually in the Chollas Creek Watershed. This presentation will discuss the monitoring challenges associated with BMP effectiveness monitoring, focusing specifically on unique monitoring configurations, flow data collection, and flow-weighted composite sampling practices where traditional measures fail. It will also provide a lessons-learned approach by offering the audience adaptive monitoring tools used to obtain representative flow data where stormwater BMPs have otherwise inhibited the ability to gather quality flow data using traditional tools.
This presentation relates to the conference theme, CASQA in the Capital: Building Bridges for Water, in regards to management of the quality and quantity of the stormwater resource in California. The presentation further relates to the Collecting and Managing Data track through a discussion of innovative flow-monitoring approaches to study BMP effectiveness. The presentation will provide for critical discussion with potential collaborators for larger-scale BMP implementation programs. The audience will be stepped through the monitoring design configuration for one of the more challenging locations, which will provide for an interactive, engaging session.
Thomas Arthur is a water resources senior scientist at Amec Foster Wheeler in San Diego, CA, and has 8+ professional years in watershed science and storm water practice. His areas of focus include TMDL regulatory compliance monitoring, surface hydrology, bioassessment, flow meter and autosampler applications, and flow-weighted composite sampling.
Carl is the Chief of the Storm Water, Culvert Inspection and Visual analysis at the Caltrans District 11 office. He has held the position since 2014 and both heads a staff of 14 and oversees several consultant contracts. The team and he are in charge of all the storm water efforts, including new construction, maintenance, mitigation and storm water monitoring in the District. The team and he also investigate the status and maintain the data regarding the condition of over 23,000 drainage systems in San Diego and Imperial Counties. They also ensure the Districts Visual and atheistic goals are maintained. He has been with the Department for over 32 years and in his tenure has been both the Design and Project Manager on numerous major roadway design projects and was also the Resident Engineer on several large construction projects. He has a bachelor’s degree in Civil Engineering from UC Irvine, a Master’s in Business from SDSU and has numerous certificates in Project Management.