WRIA 35 has conducted a Hydro Geo field investigation, hydrogeologic evaluation and water use analysis was conducted for the Alpowa Creek and Asotin Creek sub-basins. The study area included the Alpowa and Asotin Creek sub-basins as well as the Town of Anatone and Tenmile and Mill Creek sub-basins. The field investigation included a physical reconnaissance of the study area, interviews with residents residing outside the boundary of Asotin Public Utility District to determine water used characteristics such as irrigated lawn size, household population and irrigation practices, interviews with other landowners and with persons familiar with the area to determine irrigated acreage and livestock within the project area, groundwater level measurements permit exempt wells and a seepage run. An average of 2.4 persons per household and an average lawn size of 2,500 square feet were identified during the survey. A total of about 1,900 livestock are located in the basin during the year. Ground water level measurements were recorded at about 59 wells in the fall of 2008 and spring of 2009. Twenty six of the wells were measured once during the fall and again in the spring. Creek flow measurements were taken during the September of 2008 to determine groundwater gains and losses (seepage run) for Asotin Creek (North Fork, South Fork and Mainstem), George Creek, Charley Creek, Alpowa Creek, Mill Creek and Tenmile Creek.

For more information on the contents of this study or the results see the attached final report.