Abstract:
The Hydrological Routing Algorithm (HYDRA) is a computer model that simulates
the regional scale flow of water (Coe et al., 2000). HYDRA simulates a set of
physical hydrologic processes including interception, infiltration, interflow,
base flow, overland routing and channel routing. The HYDRA model uses river
transport directions based on digital
... elevation model (DEM) representations of
the land surface. River discharge is calculated at each grid cell as the
accumulated flow of water across the drainage basin surface. Lake and wetland
area and volume are calculated as a function of the local precipitation minus
evaporation, the stream flow into and out of the grid cells, and the potential
for storage of water on the surface as derived from DEMs. HYDRA is being
periodically modified to include effects of man-made structures (i.e., dams and
reservoirs) and management practices (i.e., irrigation and reservoir
operations), to account for the human controls over terrestrial hydrological
systems.
[Summary provided by NASA.] 
