The consortium hired two consulting firms and two researchers from the University of California at Los Angeles to conduct a series of applied research studies to meet the project's goal. The goal of this project was to evaluate the feasibility and benefits of using catchbasin retrofit devices as one element in local stormwater management programs. Implementing the Project Characterize Local Runoff and Select Target Pollutants Limited sampling was conducted at four sites to confirm the types and concentrations of pollutants in local urban runoff and differences between land uses. Based on these criteria and the results of sampling conducted both prior to and as part of this project, the pollutants selected for study were total suspended solids, oil and grease, and trash and debris. Evaluate Catchbasin Retrofits Before conducting field and laboratory tests, a set of objectives for evaluating retrofits was established.
Full report includes a similar comparison for all evaluation objectives.
Inserts are devices that attach to the catchbasin entrance or mount inside and thus are relatively easy and inexpensive to install. Inserts are designed to improve stormwater quality by either preventing debris and pollutants from entering the basin or by detaining and treating the water in the basin. Table 1 summarizes the results of the field and full-scale laboratory tests for the candidate devices. These calculations are illustrated for free oil and grease removal in Table 2. Calculations were also made for removal of trash and debris and total suspended solids under various scenarios.