PUD No. 1 of Chelan County - Auvil Property Groundwater Analysis

Auvil test well drillingPUD No. 1 of Chelan County (PUD) operates numerous fish hatchery programs in conjunction with its hydroelectric power generation facilities. When the PUD acquired the Auvil Property adjacent to the Chelan Falls Hatchery, Robinson Noble was selected for a multiple-phase project to locate and establish highly-productive, pathogen-free groundwater sources to support the hatchery's objectives. Temperature of the extracted ground water was of particular concern as shallow groundwater temperatures, dominated by the seasonal temperature swings of the adjacent Columbia River, exceed 55˚F roughly five months out of the year.

In the initial phase of the project, Robinson Noble and PUD personnel instrumented existing wells and a station on the Columbia River with temperature and pressure sensors to monitor the horizontal and vertical flow of warm and cool water through the shallow aquifer system. Robinson Noble also performed an extensive microgravity geophysical survey of the property to map variations in the depth to bedrock. Collectively, these efforts shaped our conceptual model of the area, leading to targeted drilling recommendations for deeper, cooler aquifer materials. Our hydrogeologists supervised the drilling of an exploratory well confirming the presence of a previously unknown, deep aquifer system just above bedrock and roughly 100 feet below the base of the Columbia River. In 2009, the small-diameter well was tested at 700 gallons per minute for a period of eight months with stable water temperatures as much as 15.5°F cooler than the Columbia River's peak summer temperature of 67°F. This deep system provides the PUD with an important future tool for mitigating water temperature issues at the hatchery.

Services provided: Hydrogeologic Investigation, Borehole and Surface Geophysical Surveys, Well Drilling and Design Services, Groundwater Development and Management, Wellfield Management