Development of a Watershed-Based Water Balance Tool for Water Supply Alternative Evaluations

Water resource management in Skagit County, Washington is becoming increasingly complex, due to multiple interests competing for limited water supplies, and the necessary balancing of land and water development strategies. Two key drivers affecting water resource management in the County are population growth (and the associated demands upon the local water resources) and in-stream flow protection. Increasing population densities and environmental regulations are forcing a new integrated water resource management approach to better meet the needs of both the natural and built environments in a long-term, sustainable fashion.The Skagit County Public Utility District (PUD), in coordination with the County and the Washington Department of Ecology, is embarking on an innovative water resource planning approach that promotes an integrated planning strategy to identify water supply alternatives for the Nookachamps Basin, a rural area expected to experience significant future growth. This approach involves the development of a watershed-based water balance tool to evaluate impacts of various water supply and wastewater management options upon the watershed. Preliminary results of the tool under development indicate that certain combinations of land use and water resource management approaches allow for the basin to accommodate significant population growth while also providing a positive impact upon the water balance (i.e., importing water into the basin). Next steps in this effort include further evaluation of management options within the context of comprehensive watershed management scenarios, followed by a charrette-style meeting to allow multiple interested parties to comment in an open forum on the ability of various scenarios to meet their specific needs. The PUD will then frame future watershed-based utility planning efforts in the context of the issues and discussions brought forth through the water balance analyses and charrette process.