Monitoring the Effectiveness of Stormwater Control Measures on Reversing Deteriorated Stream Functions in an Urban Setting

Abstract

Redevelopment of the Granite Run Mall, a nearly 100% impervious 34 ha site in Media, Pennsylvania, required upgrading the site’s 40-year old stormwater control measures (SCMs) to comply with local modern ordinances. With its headwaters adjacent to the site, Chrome Run has received the mall’s stormwater runoff for decades with deleterious effects on all levels of stream functions. Thus, the mall’s redevelopment was an ideal opportunity to examine the effectiveness of current stormwater practices and validate the approach of focusing SCM implementation in headwaters. Specifically the study aimed to determine if the damage to the receiving waters could be reversed by conducting a 3 year long Before-After-Control-Impact study. To these ends in the summer of 2016, a rigorous monitoring program was established in Chrome Run along with three control streams. Areas of investigation included hydrology, hydraulics, geomorphology, biology, and numerous physicochemical parameters. This thesis details the materials and methods employed in addition to an analysis of the pre-redevelopment data to establish the baseline conditions along Chrome Run and quantify the stream’s impairment.