Bioretention is one of the most widely use stormwater control measures to mitigate hydrologic impacts of development. Many designers are aware of the water quality benefits that bioretention has been proven to provide in studies around the world. Yet many designers and permitting agencies overlook the flow reduction and stream protection benefits that online bioretention features can provide. This presentation will present an assessment of bioretention designs implemented on a steeply sloping residential site with low permeability soils. The presenter will give a background on the design requirements, design approaches, design solutions, modeling assessment, and construction plan review challenges of the project. Results will be compared from using the National Stormwater Calculator, HEC-HMS, Rational Method, and SUSTAIN to evaluate individual features and assessing the impacts at a watershed scale for a site near Boerne, Texas. Attendees will learn the limitations of different approaches to better determine what type of modeling and reporting is appropriate for their area. This information can be used to help set performance requirements, design integrated stormwater management ordinances, and educate both decision makers and designers on the best way to structure the full suite of stormwater control measures to protect their community.