107-Seasonally Variant Spatial Variability and Implications for Watershed Modeling, Monitoring and Management.

Abstract

Many water resources issues now require careful consideration of not only the spatial variability of hydrologic processes but also the seasonal variability of the spatial variability in watersheds. Examples of such issues explored in this paper relate to the identification and management of diffuse sources of sediment contamination of surface waters in selected agricultural watersheds in North America. A description is given of what has been learned about the seasonal variability of spatial distributions of relevant flow vectors in the sample watersheds. Decisions are discussed regarding the selection and running of watershed models deemed useful for fhe estimation of downstream loads, and the identification of likely contaminant sources. Attention is given to the location and frequency of monitoring that is required for both the validation of models and the evaluation of impacts of remediation measures. Finally the need for a targeted approach to implementation of remedial measures—targeted both spatially and seasonally is addressed.