Yuba Water Agency recently awarded a $76.8 million contract to upgrade key components of its hydropower generation infrastructure in the Yuba County foothills. A joint venture company made up of Obayashi and Drill Tech Drilling & Shoring, Inc. was awarded the contract for the agency’s Colgate tunnel outage project, set to begin in the fall of 2025. The tunnel outage will focus on a four-mile-long rock tunnel and one-mile-long penstock pipe that carries water from New Bullards Bar Reservoir to New Colgate Powerhouse at the base of Lake Francis Road in Dobbins. During the outage, Yuba Water will remove rocks and debris, repair and reinforce worn parts and install a new protective valve system at the top of the penstock pipe. The upgraded valve will enhance the agency’s ability to protect downstream infrastructure and improve maintenance access without requiring the entire tunnel to be dewatered.