A key component to holistic watershed master planning and stormwater management is the identification and implementation of best management practices (BMPs) and low-impact development (LID) strategies to address urban runoff pollution. Until now, the selection of BMP and LID strategies has been limited to qualitative planning, hindering the planners’ ability to discern effective BMP/ LID practices without long-term monitoring. Consequently, the San Antonio River Authority (River Authority) lead the development of several innovative water quality modeling tools to allow quantitative water quality master planning and BMP/LID prioritization for three major watersheds in the San Antonio River Basin. The River Authority project earned a Gold Medal in the 2016 American Council of Engineering Companies (ACEC) Texas Engineering Excellence Awards, and an ACEC National Recognition Award.