Low river reveals link
In a deep Spokane River channel, surrounded by rocks that haven’t been wet in months, Nick Vinet poked a finger at the water, checking for signs of life.
The current pushed back with the futile force of water poured from a cup. It did not seem like the wild stream that Vinet, a Spokane Valley resident, tubed down just months ago. No doubt about it – the Spokane River is bumping against record low flows this summer.
“You couldn’t inner tube down this if you wanted to,” Vinet said. “You can cross it without getting wet.”
Record keepers say this year’s low is part of a trend and not a good one.
Nearly 120 years of river data for the Spokane rank this year’s end of August flows at sixth-lowest all time. Four of the lowest levels happened in the past decade or so, a span too long for the flows to be linked conveniently by drought.
Water releases from Post Falls Dam don’t explain it all, either.
Both play a part, but hydro-geologists say a third and growing influence on river levels is at play. It is reflected on the river’s surface as it passes through the city.
The influence is us, researchers say. Our growing population is taking a toll as we tap the underlying Spokane Valley/Rathdrum Prairie Aquifer to water our lawns.
“When we pump more water in the summer, the aquifer puts less water into the river,” said John Covert, a state Department of Ecology hydro-geologist. “There are more and more of us using it, and we’re seeing lower and lower flows in the summer. That’s not a coincidence. There’s a connection.”
Ours is a thirsty community, Covert said.
Spokane-area households consume about 330 gallons of water per day, with much of the water going on lawns in the summer. The number represents per-household, per-day water usage for the entire year, with summer water consumption causing usage to skyrocket.
By comparison, households in arid Tucson, Ariz., consume 170 gallons per day. Phoenix households consume 237 gallons.
Even people in Las Vegas consume less water per household than Spokane-area residents – about 302 gallons per household.
“Spokane residents like green lawns,” Covert said. “We all do. I have a green lawn too.”
In the driest months of the year, aquifer water seeping into the river makes a powerful difference. This week, utility company Avista Corp. was releasing about 330 cubic feet of water per second from its Post Falls dam, said Hugh Imhof, company spokesman. The dam keeps the water level of Lake Coeur d’Alene at an even 2,128 feet above seal level.
Any water left over is released into the Spokane River.
The easy way to understand the aquifer’s contribution to the river flow is to simply deduct that 330 cfs from the river level near Cochran Street in Spokane. That’s where the U.S. Geological Survey’s real-time water gauge is located.
The location is important because, at that point in the river, no water is disappearing from the Spokane into the gravel below. There are areas of the river where during dry months nearly all of the water disappears into the gravel, which works as a trapdoor to the aquifer.
At Cochran Street on Thursday, the river was flowing by at 554 cfs. That means more than 40 percent of the water was coming from the aquifer.
Aquifer water is not only crucial to keeping river levels from plummeting further, it’s crucial to keeping fish alive.
In the shallowest reaches of the Spokane River, water temperatures currently rise to about 74 degrees. That’s much too warm to some trout species, said Madonna Luers, spokeswoman for state Fish, Wildlife and Parks.
Trout, at least trout that survive, need cooler water to which they can retreat, and that’s where the aquifer comes into play.
Just downstream from where Vinet inspected the river’s pulse, cool water from the aquifer is seeping into the river. Water is visibly weeping from the north bank beneath the Sullivan Street Bridge in Spokane Valley.
Underwater springs surrounding the bridge abutments blow translucent cauliflower shapes onto the Spokane’s surface.
The water from the ground is a chilly 55 degrees, and it drops the river’s fevered temperature into the livable 60s. In hot dry months, these areas are brimming with trout just waiting for the remainder of the river to become livable again.
By the middle of the month, the river’s fortunes should turn around. Avista expects to begin lowering Lake Coeur d’Alene by Sept. 10.
The lake lowering will increase the dam’s contribution to the river nearly six fold in the first few months and continue pushing levels upward through December.
The aquifer takes its share, as well.
“We’re able to monitor the effect on the aquifer when Post Falls Dam is opened up, and it’s almost instantaneous,” said Rob Lindsay, water resource manager for Spokane County.
Lindsay is among those who see the health of the Spokane River as an early indicator of the aquifer’s health. When the river is repeatedly low, it is a sign that the aquifer too could be negatively affected.
Currently the aquifer seems to be holding its own. The massive watershed, which stretches from the broad valley south of Lake Pend Oreille, Idaho, to downtown Spokane, is still able to recharge fully.
Drawing more water from Post Falls Dam would help the river, but community water consumption shouldn’t be underestimated, Lindsay said.
The more water the community draws from the aquifer, the more likely it is that at some point the massive trough of water passing through gravel will be compromised.
“This is a message that we need to spread as much as we can,” Lindsay said. “Be wise about the way you water your lawn.
“An inch of water a week is sufficient for most lawns. Fine-tune your sprinkler system. Don’t overspray. Don’t water the street of the sidewalk.
“Don’t water in the middle of the afternoon. It’s better to water late in the evening or early in the morning.”
There’s been a little encouragement from water providers for consumers to conserve water, Lindsay said, and no mandatory enforcement. Newcomers moving into the area are often surprised to hear Spokane has no water rationing or watering regulations.
Lindsay thinks it will take more than rules to get the community to help the aquifer and the river.
“It’s my personal opinion that it’s going to take a cultural shift in the community,” Lindsay said. “I’m from here. I grew up thinking there was an infinite supply of incredibly clean water, but we’re coming to realize there is not an infinite supply.”