The Colorado River's Long Road to Recovery

How much does one good snow year help the Colorado River?

BY JEN PELZ

The chocolate water churning with snow melting out of the Rockies plummeted downstream as I made my way from western Colorado to Utah’s canyonlands this May. This was a good sign. The sight was the same in Glenwood Springs, Colorado, where the Colorado River roared and frothed, so loud it was hard to hear over, and at the Dirty Devil River near Hanksville, Utah. Water coursed in both rivers from bank to bank, thick with sediment, high and fast.

The Colorado River at Glenwood Springs reached its highest flow of the year on June 23, 2023 — 14,000 cubic feet per second. Picture 14,000 basketballs made of water bouncing downstream with reckless abandon every second. The river was significantly higher than in 2022, but still only half the peak it reached in wet years like 2019 and 2011. 

The lodge on the north rim of Grand Canyon National Park as seen on April 4, 2023. As of April 7, 2023, the North Rim had received over 250 inches of snowfall. E. SHALLA, NATIONAL PARK SERVICE

These high river flows are the result of heavy snowfall that blanketed the western U.S. this past winter. By the end of January 2023, the snow water equivalent — the amount of water contained in the snow — was 150 percent of normal in Arizona, Utah, and western Colorado. Snow continued to accumulate throughout the spring and temperatures remained cold, allowing snow to persist late into the season. By April the total amount of water contained in the snow was up to 161 percent of normal across the Colorado River Basin.

Mountain snowpack and water in rivers throughout the basin is vital to replenishing groundwater aquifers and boosting rivers, reservoirs, creeks, and springs that supply homes and farms. Water in rivers also supports cultural uses by Native communities, nourishes plants and wildlife, helps generate power, and supports recreation economies. A good water year also increases soil moisture, reduces the risk of wildfire, allows for dynamic high flows that transport sediment and clear river channels of vegetation, and triggers reproduction in native fish and plants. 

But one good snow year does not end a decades-long drought. Despite all the positive effects of the 2023 runoff, it’s not enough to make up for the chronically low flows we’ve seen since 2000, nor to ease unsustainable demands on the Colorado River, for a few reasons. 

First, it takes a long time to recover from a 23-year drought intensified by climate change.

The past two decades were the driest period in the past 1,200 years. The January 2023 Drought Status Update report put out by the federal government explained that "the impacts of long-term drought are often slow to build and recover," and that the effects are "compounded by the impacts of warming and aridification." The report also emphasized that water levels remained low in lakes Powell and Mead.

Second, the amount of water in the two largest U.S. reservoirs is massive. Lake Mead and Lake Powell collectively hold more than 16 trillion gallons of water. Six other reservoirs in the upper Colorado River Basin (Fontenelle, Flaming Gorge, Blue Mesa, Morrow Point, Crystal, and Navajo) hold only about 2 trillion gallons of water combined. That means the smaller upstream reservoirs recover from low water levels much faster. You may remember that, after its construction in 1963, it took Lake Powell 17 years to fill. At that time, demands on the river were significantly less than we see today and rain and snowmelt were consistently higher. 

Finally, keeping water levels up in lakes Powell and Mead depends on how much water comes in and how much water goes out every year. The reservoirs fill when more water is coming in than is being used or evaporating, and they shrink when more water is used or lost to evaporation than is replenished by river flows. Over the last 23 years, both reservoirs fell because demand is significantly outpacing supply.

As an example, Lake Powell was nearly full in 1999. The water was only six feet from the top of the dam. However, a series of dry years between 2000 and 2004 and high demand dropped the surface of the lake 100 feet and cut its volume in half. This precipitous decline spurred the U.S. Bureau of Reclamation and the seven Colorado River Basin states (Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming) to develop rules, known as the 2007 Interim Guidelines, for operating lakes Powell and Mead and to reduce demand in the lower basin states of Arizona, California, and Nevada. The new rules took effect at lakes Powell and Mead in 2008. 

From its low point in 2004, Lake Powell began a slow recovery. Over the next seven years, the lake rose 66 feet and filled up to 72 percent of capacity. A series of above-average river flows and a wet 2011 helped. However, those gains were short-lived. By 2013, the reservoir had dropped 52 feet and was more than half empty again. 

While some modest recovery occurred through 2017, Lake Powell fell 40 percent over the next five years. This was despite the 2007 guidelines and the additional water conservation measures developed by the U.S. Bureau of Reclamation and the basin states in the 2019 Drought Contingency Plans. 

On July 4, 2022, water levels dropped to an alarming elevation of just 3,540 feet. Looking down over the edge of the dam, the dark blue surface glimmered 160 feet below — Lake Powell was only about a quarter full. This low water level was within 50 feet of the critical reservoir elevation of 3,490 feet — minimum power pool — below which the dam can no longer generate power and the rate at which water passes through the dam is cut in half. Reclamation warned in August 2022 that Lake Powell could reach this critical level as early as July 2023 if dry conditions continued. 

The Colorado River below Glen Canyon Dam. AMY S. MARTIN

While the wet winter of 2023 is raising water levels in Lake Powell, it’s not enough to solve the West’s water problem. The Colorado Basin River Forecast Center expects that 2023 flows will reach 146 percent of average. Based on this projection, the predicted water level at Lake Powell at the end of the water year (September 30, 2023) is 3,575 feet (38 percent full).

While the deep snow and rushing rivers of 2023 elicited an audible sigh of relief from water managers, recovering from more than two decades of hot, dry conditions is going to take much more than one good water year. We need big changes, including using less water, to ensure that reservoir levels stabilize and, more importantly, that a healthy river system sustains lands, wildlife, plants, and the 40 million people who depend on the Colorado River. 

Jen Pelz directs the Grand Canyon Trust’s Water Program.

EDITOR'S NOTE: The views expressed by Advocate contributors are solely their own and do not necessarily represent the views of the Grand Canyon Trust.