Hillsboro, OR — June 28, 2004 —
On July 1, Clean Water Services will begin releasing water from Hagg Lake to the Tualatin River to improve water quality and protect fish and wildlife by maintaining stream flows.
During the dry summer months, scientists at Clean Water Services carefully monitor the water quality and flow of the Tualatin River to determine when to release precious stored water from Hagg Lake/Scoggins Dam and Barney Reservoir to restore river flows and protect the environment. The scientists must consider the weather forecast, the amount of stored water available in the reservoirs and the number of summer days left before requesting the release of water to the river. The goal is to augment flows to maintain water temperatures and dissolved oxygen levels that protect the fish and macroinvertebrates in the river.
“It’s a delicate balancing act,” says Water Resource Program Manager Jan Miller. “We need to release water now to protect the river, but we also have to hold back enough water to release during the most critical dry months of September and early October. I’m one of the few people in town who cheers for summer rainstorms.”
Jan uses a cadre of water quality monitors, flow meters and weather data to make daily decisions on reservoir releases. Her target is to maintain Tualatin River flows above 150 cubic feet per second at Farmington Bridge downstream of Hillsboro. The Tualatin River is fed by rain only, without a snow melt to gradually replenish the river throughout the summer. In the winter, flows swell to an average of 2,000 cubic feet per second (cfs) in the low-lying river. Starting July 1, the release rate will be 10 cfs, which equals 6.5 million gallons of water per day. Throughout July and August, the releases will average 30 cfs.
Clean Water Services was one of the original investors in Scoggins Reservoir when it was built in the early 1970s to meet agricultural irrigation and drinking water needs. In the 1990s, the District joined the Joint Water Commission in expanding Barney Reservoir on the upper Trask River to secure additional stored water.
In the last decade, Clean Water Services has acquired nearly a quarter of the basin’s stored water to restore life-giving flow to the Tualatin River during the dry summer months. Today, Clean Water Services is working with water managers throughout the basin to investigate and secure additional water sources to meet the growing industrial, municipal, agricultural and environmental water needs.
During the late summer months, Clean Water Services’ water releases from Hagg Lake and Barney Reservoir together with cleaned wastewater released from the District’s two advanced treatment facilities account for nearly 50 percent of the Tualatin River’s flow.
Clean Water Services is the sanitary sewer and surface water management utility for more than 470,000 people in urban Washington County and small portions of Multnomah County, Clackamas County, Lake Oswego, and Portland. Clean Water Services operates four wastewater treatment plants, constructs and maintains flood management and water quality projects and manages flow in the Tualatin River to improve water quality and protect fish habitat. Although Clean Water Services maintains a close working relationship with Washington County government, it is a separately managed and financed public utility.