Hot, dry conditions put pressure on water supplies
Campbell Creek, the water supply for the community of Ryderwood, is a trickle due to a major lack of precipitation in Cowlitz County. Read more on our statewide conditions webpage. Photo courtesy of Washington State Department of Health.
Months of unusually warm and dry weather continue to put pressure on the state’s rivers and streams. Although some areas saw sprinkles earlier this month, rivers across the state continue to recede. In some cases, rivers are hitting new record lows. The Naselle River in Southwestern Washington established a new historic low flow when it dropped to 16 cubic feet per second (cfs) this week. That’s roughly half of its normal flow of 37 cfs.
High temps in August
Although wildfire smoke moderated the heat a bit, the average daily temperature during the first half of August was about 3 degrees above normal. This contributed to more days above 90 degrees than usual. The Vancouver airport hit 90 degrees or hotter on 28 days this summer. That’s more than Spokane, which broke 90 degrees on 23 days. The average over the previous 20 years for Vancouver is 11 days. For Spokane, about 19.
Thankfully, this summer, we aren't expecting an official water supply drought emergency to be declared. It's been hot and dry, but water supplies so far haven't met the statutory threshold. Under state law, a drought emergency is defined by a two-prong test:
· An area has or is expected to receive 75 percent or less of normal supplies AND
· Undue hardships are likely to occur as a result.
Official drought declarations provide us flexibility to authorize emergency wells and water withdrawals.
Tracking impacts
We’re working with other state agencies to track impacts from the warm and dry conditions.
The Department of Health tells us that multiple drinking water systems in western Washington have taken measures to reduce demand. Actions range from requesting voluntary or mandatory conservation (e.g., lawn watering restrictions) to more serious measures like hauling water.
Larger municipalities like Seattle and Tacoma say their water supplies should be fine for the season.
For fish, warm water temperatures can block migration. Emergency fishing closures are in effect on parts of the Columbia River to protect fish trying to find refuge in cooler water, according to the Department of Fish and Wildlife.
We are continuing to regulate water users in some parts of the state to protect senior water rights and adopted instream flows. Curtailment notices or orders have been issued in the Chehalis, Walla Walla, Methow, Similkameen, Wenatchee, and Skagit watersheds.
Read about more impacts on our water supply conditions webpage. We update it weekly.