Protecting streamflows and fish in the Walla Walla River and Mill Creek
In recent days, community members along Yellowhawk Creek near Walla Walla have noticed lower-than-normal flows in the creek. The reduced flows are part of a larger effort to protect water supplies in the greater Walla Walla River Basin and allow fish to safely migrate to the upper reaches of Mill Creek.
As the demand for water increases and supplies dwindle in the Walla Walla River Basin, the Washington Department of Ecology is working with the State of Oregon, the Confederated Tribes of the Umatilla Indian Reservation and stakeholders on both sides of the state border to find solutions. One of those projects involves temporarily using water rights from Oregon in a new program to protect fish.
According to the agreement, water rights from Oregon have been put into a temporary trust, protecting the water from being diverted for other uses as it flows through Mill Creek and to the Walla Walla River. The temporary trust began Aug. 1 and will continue through Sept. 30.
The goal is to maintain a minimum of eight cubic feet per second of water in Mill Creek before it enters the Walla Walla River. To achieve this, Ecology uses control points to manage water. This means that some tributaries may see less water than typical for this time of year.
The temporary changes in water management mean that less water is being diverted into Yellowhawk Creek, but we are committed to maintaining streamflow in the creek and fisheries managers are available to respond, if conditions change. Ecology’s watermaster for the basin is closely monitoring water levels, and will move as much water as possible down Yellowhawk Creek once the increased flow in Mill Creek is satisfied.
“Fisheries managers from Oregon, Washington and the Confederated Tribes of the Umatilla Indian Reservation determined that running protected water down the mainstem Mill Creek would be preferrable to running it down Yellowhawk, which was the historic practice,” said Jaime Short, water resources section manager for Ecology’s Eastern Region. “Increased flows in Mill Creek will allow fish to migrate to the upper portions of the basin and provide better habitat.”
This temporary water trust is only one of the many efforts underway to increase water supplies and improve habitat in Mill Creek. For example, the U.S. Army Corps of Engineers is currently working on a weir notching project to make it easier for fish to get up stream. By increasing the summer flows in Mill Creek, Ecology can help this effort.
About the Walla Walla Watershed Strategy
Ecology was given authority in 2023 to enroll water rights, including rights from Oregon, into Washington’s Water Right Trust program. This effort is part of the overall Walla Walla Watershed Strategy – an effort to improve streamflows and water supplies in the Walla Walla River basin over the next 30 years.
Together with the Confederated Tribes of the Umatilla Indian Reservation, the state of Oregon and stakeholders on both sides of the state border, the initiative answers the decades-long challenge of meeting the basin's growing water needs for today, tomorrow and beyond.
As the strategy evolves, the goal remains to improve streamflows and water supplies in the Walla Walla watershed. It will do this by focusing on:
- Floodplains, critical species, habitat, and water quality
- Water supply, streamflows, and groundwater
- Land use and flood control
- Quality of life
- Monitoring and metering
Questions
For questions about the temporary water trust and changes in water management in the Walla Walla basin, contact Ecology Water Resources section manager Jaime Short, 509-990-7636 or Ecology watermaster Eric Hartwig, 509-540-7680.
