Simple Method for Using Precomputed Hydrologic Models in Flood Forecasting with Uniform Rainfall and Soil Moisture Pattern

Abstract

Transforming a weather forecast into a flood hydrograph for a watershed requires a series of steps: (1) gathering and pre-processing data about the current conditions of the watershed, such as soil moisture, snow cover, etc.; (2) creating or modifying a hydrologic model; (3) running the model; and (4) assessing the results. Adequately performing all these steps in a short period of time as a major storm is approaching is in many cases extremely difficult. In this paper the authors present a method that enables performing the steps 2, 3, and 4, in advance of a flooding crisis by determining a large set of potential “scenarios” (combination of parameters), running a model for each, and storing the results. The researchers analyze a way to create the scenarios so to maximize the uniformity of their distribution on the parameters space. They present a simple technique to retrieve the stored result that best matches the current conditions. The authors illustrate this method in a test case, for which seven model parameters were selected and more than 2,000 scenarios were generated and pre-computed.