An important problem in terrain analysis is modeling how water flows across a terrain and creates floods by filling up depressions. In this Forum, we will discuss a number of flood-risk related problems: Given a terrain T, represented as a triangulated xy-monotone surface with n vertices, a rain distribution R and a volume of rain V, determine which portions of T are flooded and how water flows across the terrain. We present efficient algorithms for flood-risk analysis under both single-flow-direction (SFD) as well as multi-flow-directions (MFD) models — in the former, water at a point can flow along one downward slope edge while in the latter, water can flow along multiple downward slope edges; the latter more accurately represents flooding events, however, it is more computationally challenging. We will also discuss these problems when there is uncertainty in terrain data, which must be incorporated into the terrain analysis.

Bio

Prof. Agarwal earned his PhD in Computer Science from the Courant Institute of Mathematical Sciences at New York University. He joined Duke University in 1989 where he is currently the RJR Nabisco Professor of Computer Science and Mathematics. He served as the Chair of the Department of Computer Science from 2004-10 and again from 2017-20. His research interests include geometric computing, spatial databases, ecological modeling, geographic information systems, sensor networks, computational molecular biology, and robotics. A Sloan Fellow, an ACM Fellow, and a National Young Investigator, Dr. Agarwal has authored four books and more than three hundred fifty research articles. He serves or has served on the editorial boards of a number of journals and on the advisory boards of many institutes and centers.