Lake Powell Is At Critical Water Level
Lake Powell’s water level fluctuates seasonally in response to spring runoff, scheduled dam releases, precipitation, and evaporation. However, there has been a steady decline in water levels since 1999, and the past several years have seen record lows. Chalky, white calcium carbonate deposits dubbed “bathtub rings” line the exposed walls of Glen Canyon, providing visual evidence of past water levels. As of this writing, the water in Lake Powell sits 175 below the historic high mark (live tracking of water levels here).
Water levels are dropping due to a combination of factors. Given that the original Colorado River Compact did not account for population growth and climate change, the calculus of water usage balanced against water inflow is antiquated and more water is lost each year than that is gained. This trend is only expected to continue as climate change increases drought severity in the American Southwest.
As water levels in Lake Powell drop, Glen Canyon and this particular stretch of the Colorado River have once again taken center stage in the national environmental movement. The precipitous decline in reservoir water levels in recent years is making a future in which hydropower generation from Glen Canyon Dam becomes impossible. Declining water levels also have significant implications on Lake Powell’s recreational use. As channels narrow, boat congestion increases, and boat launches and ramps built decades ago are being moved and/or retired as the shoreline recedes.
As water levels drop, Glen Canyon is a landscape in transition, and the opportunity to restore the previously lost canyon and consider removing the dam is becoming more viable. Previously submerged side canyons are being revealed, historic features are resurfacing, and the water is falling away from notable geologic features such as Cathedral in the Desert. Organizations such as Glen Canyon Institute are helping facilitate scientific studies assessing ecological restoration in the canyon and as well as how water management could shift to support the restoration of Glen Canyon.
But in the wake of an unprecedented amount of snow in the Western United States this winter, questions abound about how much water levels will rise this spring and what that means for Glen Canyon.
Implications of 2023’s Historic Snowpack
Snowfall across the Western U.S. has reached unprecedented levels this winter. At the end of April 2023, Colorado state snowpack was greater than 140% of average, and Utah’s snowpack had already broken all previous state records. Across the Upper Colorado River basin, snowpack is greater than it has been at any point in the past decade. Some experts are estimating that water flows into the Colorado River from snowpack will be 177% of average, and Lake Powell could rise by as much as 25% to reach 50% capacity.
While all of the water locked up in this winter’s high snowpack bodes well for the river system, it’s not obvious how much of that snowmelt will actually make it to the reservoirs. The extent to which snowpack will impact Lake Powell levels depends on the trajectory of its melt and factors such as soil moisture levels, future precipitation, temperature, and evaporation rates. Dry soil has the capacity to take up more water, limiting the amount of water that ultimately reaches the river basin. If temperatures rise rapidly, there will also be greater evaporation rates which would limit how much of the moisture contained in the snowpack actually reaches the Colorado River Basin. The West has been in a drought period for decades, and it will take more than one year of high snowpack to reverse those effects in any meaningful way.