GROUPED RESPONSE UNITS FOR DISTRIBUTED HYDROLOGIC MODELING

This paper introduces a method for distributed hydrologic modeling tha t 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 tha t can make maximum use of remotely sensed data such as rainfall from w eather RADAR and land cover characteristics from LANDSAT or SPOT satel lites. Other remotely sensed data such as snow-cover extent and initia l soil moisture can also be based on satellite data and be directly in corporated in the model. The method consists of grouping hydrologic re sponse units that have similar response characteristics on the basis o f classified land-cover maps. Model parameters are unique to individua l land-cover classes. This reduces the need for model calibration and allows for the transfer of model parameters in both ti mc and space. T he model was applied to four watersheds in Southern Ontario. It was ca librated on the Grand River watershed and then applied to the three ot her watersheds without further calibration of the hydrologic parameter s. Only the river roughness was adjusted.