Polk and Lincoln Counties are facing increasing water demand and increasingly scarce water supplies. Both counties have been working collaboratively to explore whether a storage reservoir on the South Fork Siletz River at the site of the historic town of Valsetz could meet water demands projected for 2050 for water providers and agricultural users. This potential storage facility would be located near the coastal mountain divide. Impounded water would be diverted to the west to serve Lincoln County and to the east to serve Polk County. There also is the potential to serve the greater regional area including Benton, Marion and Yamhill County citizens. The South Fork Siletz River and the Luckiamute River would be used to convey water to withdrawal points located lower in each basin.
The purpose of this study is to conduct an appraisal level assessment of potential environmental effects and benefits of the Valsetz water storage project. The assessment focuses on three storage concept alternatives determined by dam height and reservoir storage. This analysis serves as a preliminary, concept-level review of the resources that may be affected if a project were developed. This initial investigation relies on existing information, an extremely limited amount of field data and some preliminary modeling and analysis. This is a first step in understanding potential effects in the area that would be inundated by a project and the Siletz and Luckiamute Rivers. Further investigation and technical studies will be required to definitively evaluate the magnitude and type of impacts and feasibility of project development.