Spatial discretization effect on flow simulations using the CEQUEAU distributed model.

Abstract

This paper discusses the effect of the spatial discretization of a basin on flow simulations using the CEQUEAU model. This is a distributed model that was developed by the National Scientific Research Institute of the University of Quebec, Canada. CEQUEAU has been used in several countries to model runoff and by studies to compare models generated by the World Meteorological Organization (WMO). This model discretizes the basin into square elements, calculating water balance square-by-square, taking into account precipitation, temperature, percentage of lakes, percentage of forest, etc. The main objective of this work was to identify criteria to determine the optimal grid size for the discretization of a basin, assuming adequate representation of precipitation. Eight basins in the Mexican Republic with different sizes and different climates were analyzed. The physiographic characteristics were determined with SIG-Idrisi. In addition, CEQUEAU was calibrated and validated daily with various square sizes, evaluating the certainty level with numerical Nash criteria and graphs. Based on the results from the experimental design proposed, a suitable mathematical regression model was built to obtain the optimal spatial discretization grid size using easily-obtained physiographic parameters as explanatory variables.