Parallel Flow-Direction and Contributing Area Calculation for Hydrology Analysis in Digital Elevation Models

C. Wallis
D. Watson
David G. Tarboton, Utah State University
R. Wallace


This paper introduces a set of parallel algorithms to determine the hydrological flow direction and contributing area of each cell in a digital elevation model (DEM) using cluster computers in an MPI programming model. DEMs are partitioned across processes relevant to the physical layout of the terrain such that processes with adjacent ranks calculate flow direction and contributing areas for physically adjacent partitions of the DEM. The contributing area algorithm makes use of a queue to order the consideration of cells such that each cell is visited only once for calculation and cross-partition calculations are handled in an efficient and order-independent manner. This algorithm replaces a serial recursive algorithm included as part of the TauDEM hydrology analysis package.