Characterization of Stormwater Physicochemical Parameter Transport Prior to Low Impact Development Installation

San Antonio, Texas (USA) is a rapidly growing city. As urban development accelerates watershed alterations, low impact development best management practices (BMP) will become increasingly necessary to mitigate negative effects on water quality. Here, I present results from the pre-construction phase of a monitoring project that will test a BMP's efficacy on the University of Texas at San Antonio 1604 (Main) Campus. The study area is a 292 meter long stormflow draining an area of impervious cover. Stormwater samples were collected from August 2018 to June 2019. Correlations between ten analytes, changes in concentrations and loads for the analytes between two locations (entry and exit of the stormflow channel), and correlations between the analytes and length of intervening dry period as well as flow rate were examined. Dissolved solids strongly correlated with conductivity and nitrate, while suspended solids strongly correlated with phosphorus and pH. Conductivity, dissolved solids, and organic carbon concentrations increased downstream while suspended solids decreased. Nitrate, calcium, and magnesium loads decreased downstream. Dry period length moderately correlated to total nitrogen concentrations while flow rate strongly correlated to suspended solids. The overall improvement in water quality was minor along the grass-lined channel. Future research will seek to answer if the upstream/downstream changes and correlations in analyte concentrations improve as a result of the planned bioswale installation as well as the effects of dry period length and rate of flow on BMP performance.