Grouped Response Units for Distributed Hydrologic Modeling

TLDR

The study presents a distributed hydrologic modeling approach that removes the requirement for small computational cells while still computing runoff for homogeneous watershed subareas. The georeferenced model groups hydrologic response units by land‑cover classification, assigns unique parameters to each class, incorporates remotely sensed rainfall, land cover, snow cover, and soil moisture data, and was applied to four Southern Ontario watersheds with only river roughness adjusted. The approach reduces calibration effort and enables transfer of model parameters across time and space, as shown by successful application to three additional watersheds after calibration on the Grand River.

Abstract

This paper introduces a method for distributed hydrologic modeling that eliminates the need for small computational areas while maintaining the requirement of computing runoff for homogenous watershed subareas. The model is designed from the ground up as a georeferenced model that can make maximum use of remotely sensed data such as rainfall from weather RADAR and land cover characteristics from LANDSAT or SPOT satellites. Other remotely sensed data such as snow‐cover extent and initial soil moisture can also be based on satellite data and be directly incorporated in the model. The method consists of grouping hydrologic response units that have similar response characteristics on the basis of classified land‐cover maps. Model parameters are unique to individual land‐cover classes. This reduces the need for model calibration and allows for the transfer of model parameters in both time and space. The model was applied to four watersheds in Southern Ontario. It was calibrated on the Grand River watershed and then applied to the three other watersheds without further calibration of the hydrologic parameters. Only the river roughness was adjusted.