Methods for evaluation of ultra-urban best management practices

In response to increasing regulation of stormwater discharges, a new generation of proprietary treatment systems targeted for space-limited situations has recently emerged on the market. Application of these “ultra-urban best management practices” (BMPs) is rapidly increasing without proven effectiveness as stormwater BMPs. Based on extensive field monitoring, the work presented in this dissertation provides an evaluation of two ultra-urban BMPs and a method for direct comparison of different systems.; A Vortechs™ Model 3000 and two configurations of the Stormvault™ (Models SV68x1 and SV68x2) were monitored during 2001. Both Stormvault™ configurations effectively reduced the effluent to low event mean concentrations (EMCs) which were comparable to reports for conventional BMPs. Confidence intervals (95%) on the mean indicate an upper level of EMC_out at 12.5 mg TSS/L and 0.11 mg Zn/L for Model SV68x1. Confidence intervals (95%) on mean values had an upper level of 25 mg TSS/L and 0.14 mg Zn/L for Model SV68x2. Under the specific testing conditions, Model SV68x2 pollutant mass removal efficiencies are comparable to many conventional systems. Differences between system results are attributed to variations in influent loadings.; The Vortechs™ Model 3000 tested displayed erratic results. Mean TSS EMC_out was 64.5 mg/L with an upper confidence level (95%) of 80 mg/L. Mean Zn EMC_out was 0.22 mg/L with an upper confidence level of 0.28 mg/L. The system is not as effective at reducing receiving water pollutant loads in terms of either EMC _out or mass removal efficiency compared to conventional stormwater BMPs.; Accumulated material in the Stormvault™ was not subject to resuspension, whereas, the Vortechs™ was subject to pollutant wash-out during storms with intensity greater than 0.7 in/hr.; A one-dimensional plug flow model was successfully applied to the Stormvault™. Results indicate that advection and vault length have the most significant influence on system performance. Regression techniques were used to identify relationships between factors influencing pollutant removal efficiency as well as outlet concentrations under a variety of rainfall and runoff conditions. The simple equations can be used to directly compare multiple systems for a given site, between watersheds, or to evaluate changes in performance due to modified system design.