Over 600,000 people depend on the Spokane Valley Rathdrum Prairie aquifer for water. We know that the Spokane River is connected to the aquifer and is the largest source of recharge for our water supply. Our aquifer also contributes water to the river. Being good stewards of the river and all its wildlife means reducing water consumption, especially during the summer months when river flows are lowest. Water from this year’s snowpack was below average and this spring has been unusually dry. Spokane is currently facing moderate to severe drought conditions, and it is only June 10th!
So, what happens to the river during a summer drought? When river water gets low and slow, the water in the middle Spokane River heats up quicker, especially in the shallow portions of the river. Reaches near the Idaho state line are only receiving surface water from Lake Coeur d’Alene which is affected by warm air temperatures. Warm water holds less dissolved oxygen than colder water. Increased temperatures cause fish to increase their breathing and heart rates, thus requiring more oxygen. Warm, slow river conditions can also lead to increased algae in shallow areas. Bacteria that decompose the algae require oxygen, and so their increased presence in the water decreases available oxygen for fish. Fish, like our beloved Redband trout, are ectotherms and their body temperatures are regulated by their surroundings. Such warm, oxygen depleted conditions cause stress and even death for native fish.
In the lower Spokane River, where cooler groundwater from the aquifer contributes to the flow, temperatures are not as high, but increased summer water demand for irrigation causes the water levels to decrease in these reaches. The low water levels reduce available habitat for native trout and makes it difficult for fish to swim to cooler waters. The more water we conserve as a city, the better summer conditions will be for fish and the river ecosystem in general.
Residential homes account for the majority of water consumption in the City of Spokane. As residents, we can have the greatest impact on improved water levels and flow rates in the river. There are ways to reduce your water usage. First, start by calculating how much water is used in your household. This website has a water usage calculator and plenty of tips on ways to make your home more water efficient: https://www.home-water-works.org/calculator
Let us all contribute to improved conditions in the river this summer!
References
1. City of Spokane Water Department. (2020). City of Spokane Water Conservation Master Plan. https://static.spokanecity.org/documents/publicworks/water/water-conservation-master-plan-2020-04-27.pdf
2. Office of the Washington State Climatologist. (2021, May 6). May 2021 Report and Outlook. https://climate.washington.edu/wp-content/uploads/2021May.pdf
3. Fuchs, B. (2021, June 3). U.S. Drought Monitor: Washington. National Drought Mitigation Center. https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?WA
4. Stevens, G., Hess, A., Covert, J., & Patrouch, J. (2015). Spokane Valley-Rathdrum Prairie Aquifer Atlas 2015 Edition. https://www.spokanecounty.org/DocumentCenter/View/3178/2015-Edition-SVRP-Aquifer-Atlas-PDF
5. USGS. (n.d.). Dissolved oxygen and water. https://www.usgs.gov/special-topic/water-science-school/science/dissolved-oxygen-and-water?qt-science_center_objects=0#qt-science_center_objects
6. Spokane County Water Resources. (n.d.). Conservation/Drought. https://www.spokanecounty.org/1207/Conservation-Drought