Scoggins Dam at Hagg LakeRecord-setting temperatures this spring have prompted Clean Water Services to begin releasing cool water from Hagg Lake and Barney Reservoir today, marking the second year in a row that releases have started early. The annual releases typically occur in July when stream flows drop and temperatures increase. The water is necessary to improve water quality and support fish and wildlife in the Tualatin River Watershed and scientists closely monitor the river to determine when more water is needed.
"For the second year in a row we are releasing water earlier than normal,” said Water Resources Analyst Jamie Hughes. “The only source of water in the Tualatin River Watershed is rainfall so another dry winter and spring has resulted in less water in streams and the river.”
Knowing when and how much water to release is an intricate balancing act based on stream flow, weather, water quality conditions in the Tualatin River, and the amount of water in the reservoirs. A network of continuous monitoring data from United States Geological Survey, Oregon Water Resources Department, Clean Water Services and other groups helps determine when and how much water is released. “We have to release enough water now to cool the river and sustain flows in the summer and through the dry fall months," said Hughes.
In an average year, Clean Water Services releases about 25 million gallons of water per day in July and August, and about 35 million gallons per day in September and October to cool temperatures, enhance water quality, and provide habitat for fish and wildlife. In order to improve water quality, Clean Water Services maintains a flow of 165 cubic feet per second (cfs) in the Tualatin River at Farmington Bridge downstream of Hillsboro. By late summer, more than 70 percent of the flow in the lower Tualatin River is from Clean Water Services' water releases from Scoggins and Barney Reservoirs, and its two advanced treatment facilities in Hillsboro and Tigard.
A portion of the released water is used to restore stream flow and improve water quality in key tributaries of the Tualatin River. Clean Water Services works closely with the Tualatin Valley Irrigation District and local farmers to send water through their distribution system and release it into tributaries including McKay Creek, Dairy Creek and Gales Creek.
Clean Water Services was one of the original investors that built Scoggins Dam in the early 1970s for agricultural irrigation, drinking water, and flow augmentation. With the Joint Water Commission, it expanded Barney Reservoir in 1998 to secure additional stored water. Clean Water Services now controls nearly a quarter of the stored water in the Tualatin Watershed and is working with water managers to meet growing industrial, municipal, and environmental water needs.
Everything we do at Clean Water Services aims to protect public health, while enhancing the natural environment of the Tualatin River Watershed. Combining science and nature, we work in partnership with others to safeguard the river's health and vitality, ensure the economic success of our region, and protect public health for more than 560,000 residents and businesses in urban Washington County.
Government & Public Affairs Manager
Clean Water Services