Northwest Water Supplies Dropping Amid Drought Conditions
The hottest June on record for Oregon and Washington came on the heels an unusually warm winter and spring. Now, Northwest rivers are running at or near all-time lows and cities with water reserves are drawing them down.
Some towns have already issued water advisories and asked residents to cut back voluntarily. Even the cities with lots of water, like Portland and Seattle, are finding they have less to work with.
The city of Portland plans to start tapping its secondary water source on Thursday, adding 20-30 percent well water to supplement what comes out of its Bull Run reservoirs. Without snowpack to draw from, the city of Seattle recently changed the outlook on its water supply from "good" to "fair" following two months of hot, dry weather that increased water consumption.
With the traditionally dry month of August still to come, officials say they're worried some cities might need to tap emergency supplies before fall rains arrive. And with water supplies so depleted this year, they say, it's looking more likely that the winter won't fully replenish them.
The city of Portland has nearly 10 billion gallons of usable water stored in its Bull Run reservoirs near Mount Hood. But the reservoirs have been in "draw-down" mode – taking out more than they have coming in from the Bull Run River – since May. Draw down usually starts in July, according to Steve Kucas, environmental compliance manager for Portland Water Bureau.
"So, it started much earlier," he said. "You can see the exposed banks, and that shows how much it's drawn down so far this summer."
The banks of one reservoir are lined with tree stumps that were under water all winter. It's dropped 25 feet already, and Kucas said it can drop an additional 50 feet before it's tapped out. The city has a second Bull Run reservoir that's still full. But with sweltering temperatures over the past two weeks, the city has seen water demand surge to 150 million gallons a day. That's way up from recent years.
Portland recently officially entered moderate drought status, although city leaders delivered assurances that despite the status change, residents need not worry about running low on water or facing mandatory conservation measures.
Not every city has water reservoirs and groundwater wells. Some cities rely on water withdrawals from rivers, many of which have extremely low stream flows this year. Diana Enright is a water policy analyst with the Oregon Water Resources Department. She says several Oregon cities have asked their residents to use less water and help stretch their dwindling supply.
"We are seeing conditions in Oregon that we normally see in the middle of August," she said. "We're seeing low stream flows in places we might not normally see those. In coastal areas, we are extremely concerned about how low the stream flows are there."
As hot, dry conditions continue, her agency is asking cities to call for help if they find they don't have enough water to make it through the summer without rain.
"They have to think about: Can they get their customers through the fall without any additional precipitation?" she said.
In Seattle, that question seemed clear cut last spring when the city's reservoirs were full of rain water. But then came two parched summer months. As conditions changed, Seattle reassessed its water reserves and downgraded its outlook on supply
Alex Chen, director of water planning for Seattle Public Utilities, says the city usually relies on snowpack to refill its reservoirs over the summer, but this year it had to count on rainwater instead. So, the city's water supply looked good until the hot weather hit.
"Conditions are changing," Chen said. "We are seeing people use more water, and we're seeing less water go into our reservoirs from streams, so that is informing our outlook."
Although officials in Portland and Seattle say residents don't need to cut back, they are advising people to use their water wisely.
Scott Oviatt, snow survey supervisor for the Natural Resource Conservation Service in Oregon, says at the rate we're going, with so little snowpack and such low stream flows, Northwest water supplies will be so depleted by the end of the summer that they probably won't be fully restored over the winter.
"Unfortunately, I don't think we can rebuild them in one snow season or one water year – just due to the extreme shortages we've experienced this year," he said. "It's going to be a multi-year process through time to replenish our groundwater as well as our surface water."
Oviatt says it would take above average fall precipitation and much cooler conditions this winter to avoid starting out next year with a water supply deficit.
Copyright 2020 EarthFix. To see more, visit .