Unlocking a Solution for a Complex Hydrologic Issue Using Hydraulic Modeling

The 1,790 square mile watershed that contributes to Buffalo Lake, Texas, consists of thousands of dry ponds or natural depressions in the terrain known as playas. Depending on the sizes of the playas and the storms, the playas may fully or partially contain all upstream surface runoff, making the effective contributing drainage area highly variable. Having a variable contributing drainage area presents a considerable challenge to solve using traditional lumped hydrological modeling tools. The recent analyses sought to apply a more physically based approach using a combined two-dimensional (2D) hydrologic and hydraulic model using the USACE’s HEC-RAS (version 6.3.1) software to more accurately account for complex watershed terrain in establishing the contributing drainage area for extreme events and explore alternatives to traditional approaches for calibrating models for complex watersheds.