Coupling Surface and Subsurface Hydrology in Complex Terrain

Watershed function, including a watershed’s ability to provide clean, available water, is often significantly altered by the local complexity of the land surface and underlying soils.  Understanding that complexity requires models that can first represent the complexity and next solve for real-world scenarios of water conditions accurately and efficiently.  The new mathematical formulation, implemented in DOE’s Advanced Terrestrial Simulator (ATS), allows scientists to accurately predict how water flows both below and on the surface of these complex landscapes, including how it partitions between groundwater and surface runoff to streams.  In this work, the method was derived, tested against a series of benchmark problems, and shown to be more accurate than previously used methods on complex landscapes.

This and other advances in ATS allow scientists to accurately simulate the water cycle in complex landscapes, including cases of post-fire storms on patchy burn scars and variable depth-to-bedrock.  This capability takes a major step toward better predictions of water availability and quality in realistic watersheds.