Evaluation of Urban Stormwater Pollutant Loadings Using Hydrologic Simulation Program, FORTRAN (HSPF) and Optimization of Urban Stormwater Best Management Practices (BMPs) PDF Download

Author: Peter Paul Rausch
Publisher:
ISBN:
Category : Bacterial pollution of water
Languages : en
Pages : 118

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Book Description
The 2008 Spring Creek Fecal Coliform Total Maximum Daily Load (TMDL) attributed 13.7 percent of fecal coliform load to urban runoff and recommended a stormwater management plan (SWMP) be developed to guide best management practice (BMP) implementation for stormwater runoff control. To improve understanding of pollutant sources, behaviors, and loadings within the Spring Creek Watershed, and in turn guide development of the SWMP, an evaluation of fecal coliform, total suspended solids (TSS), and total phosphorus (TP) loadings from urban stormwater to Spring Creek was conducted. For fecal coliform and TSS, results from an existing, calibrated Hydrologic Simulation Program - FORTRAN (HSPF) model of the Spring Creek Watershed (Schmitz, 2011) were used to understand accumulation and washoff behaviors, as well as the significance of the urban stormwater load in relation to loads from the entire watershed. The urban area of focus is the city of Hill City, SD. Modeled results were compared for the years 2002 and 2010 as periods of dry and moist flow conditions, respectively. Results indicated that further study is required to understand the fecal coliform processes in the Schmitz model. However, the model indicated that the TSS load from Hill City stormwater in 2002 and 2010 accounted for 27 percent and 6.8 percent of the total TSS load in Spring Creek at the inlet to Mitchell Lake from March through October, respectively. This indicates a greater impact to Spring Creek during lower flows. During both periods, 70 percent of modeled daily average TSS concentrations in Spring Creek exceeding the single sample maximum of 53 mg/L occurred on days when precipitation was recorded in Hill City. This indicates that Hill City stormwater has a major impact on the daily water quality of Spring Creek. In addition, correlation of observed TSS and TP concentrations from 2002 and 2010 produces a correlation coefficient [(R2)] greater than 0.9. This indicates that removal of TSS from stormwater will inherently result in removal of TP. In addition to the pollutant analysis, a method for optimizing and recommending urban stormwater best management practices (BMPs) was developed for the SWMP. Because Spring Creek is currently impaired due to fecal coliform, emphasis was placed on this pollutant. Research has concluded that wet ponds and infiltration BMPs are the most effective for fecal coliform reduction (Clary, et al., 2008). To reduce high maintenance costs associated with sediment removal from these BMPs, it was recommended that they be implemented in series with dry ponds and vegetated swales. This will also reduce TSS load to Spring Creek, thus reducing the TP load. Wetland BMPs were not recommended for the Spring Creek Watershed due to potential TP production. Over 60 BMP alternatives were developed for the SWMP, each including estimates for initial cost, life cycle cost, and seasonal fecal coliform reduction. Sixteen optimum BMP alternatives were identified to treat all catchments with an estimated total initial cost of 5574,000 and total estimated fecal coliform reduction of [111 * 10'9] colony-forming units (cfu) per recreation season (May-September).