Drones to be used to monitor effects of low water flows on threatened bull trout

YAKIMA - Starting July 9 and continuing into the fall, Washington Department of Fish and Wildlife (WDFW) staff will use a series of drone flights to assess the effects of low water flows on bull trout movement and migration in Kittitas and Yakima counties. This work is particularly important this year as these counties are experiencing drought conditions.

Bull trout are listed as threatened under the federal Endangered Species Act. As the summer progresses and water levels drop, conditions may develop that create barriers to fish passage. Biologists will use the data collected during the drone flights to identify areas that may initiate fish rescue efforts due to these low water conditions.

Drone flights will take place over the lower reaches of tributary streams and follow those streams to U.S. Bureau of Reclamation (USBR) reservoirs within the Yakima and Naches River basins. The flights will originate from lands managed by either the USBR or the United States Forest Service and will take place two to three times per water body between July 9 and the end of November. If there is a need to take measures to restore fish passage, additional flights could occur.

Specific flight dates have not been set as they will be conducted according to water level, weather, and site-specific conditions as the season progresses. Each flight mission will take approximately two to four hours to complete.

"We use the images and video footage we get from the flights for maps of the stream reaches to see the loss of water," says Josh Rogala, Fish Passage Biologist for the Department's Region 3 Habitat Program. "This, in addition to ground surveys, will help us prioritize our work to increase the chance of survival for bull trout in these tributaries and is a visual tool showing the degree of water loss."

Drone flights will follow all FAA and WDFW policies and will be restricted to daylight hours, Monday through Friday. Pilots will maintain line-of-sight with their drone for awareness of potential disturbance to wildlife or people. Pilots will cease operations if flight conditions become unsuitable to fly safely or responsibly. No area closures or significant public impacts are expected.