On behalf of dam owner/operator Chelan County Public Utility District, Cornforth Consultants commissioned DA Smith to conduct a year-long, multi-hole core drilling program starting in late 2025 to measure in situ stresses within the Rock Island dam located near Wenatchee, Washington. The Rock Island dam is a FERC-regulated, 3,800-foot-long reinforced concrete hydroelectric dam capable of generating 660 MW and was the first dam to be built on the Columbia River.
The investigative program comprises a series of nearly two dozen vertical PQ and 6-inch-diameter core holes up to 140 feet deep drilled along the crest of the dam. Concrete and foundation bedrock core samples are being collected for mechanical properties testing. In the course of drilling, DA Smith is conducting over 120 USBM BDG in situ stress measurements to develop a comprehensive horizontal stress profile across the dam. Holes are being completed by DA Smith with a variety of monitoring instruments including inclinometers, extensometers, vibrating wire piezometers, and thermistors.
Work is underway in 2026.