Story at a glance
- The U.S. Bureau of Reclamation opened up the flow down the Colorado River and downstream to Lake Mead on April 24.
- The effort sent a gush of water at 39,500 cubic feet per second (cfs) and lasting 72 hours.
- The desired effect: push sand and sediment out of the riverbed below the dam to build up sandbars further down the river.
LAS VEGAS (KLAS) — Satellite images of the Colorado River provided by NASA show the powerful rush of water out of Glen Canyon Dam in late April that successfully moved sand down the river.
The U.S. Bureau of Reclamation opened up the flow down the Colorado River and downstream to Lake Mead on April 24, sending a gush of water at 39,500 cubic feet per second (cfs) and lasting 72 hours. The desired effect: push sand and sediment out of the riverbed below the dam to build up sandbars further down the river. Those sandbars provide camping spots for people along the river.
The image slider below shows the result, particularly in the area around Horseshoe Bend, one of the most-photographed spots on the Colorado River. In the “after” image, the burst of water coming out of Lake Powell is still visible as a white splotch just below Glen Canyon Dam.
Since this “high-flow experiment,” releases from Lake Powell have dropped to a range from 14,000 cfs to 19,000 cfs, depending on the time of day and the day of the week. Flows are generally higher in the afternoons and evenings, according to the Bureau of Reclamation.
The amount of water flowing out of Lake Powell has increased because of the heavy snowpack in the Colorado Rockies and other areas in the Upper Colorado River Basin. That increased flow is happening every day, unlike the short-lived high-flow experiment.
Photos from 2012 provided by the U.S. Geological Survey show how the higher flow can reshape the river:
Lake Mead’s level has risen about a foot and a half since May 3, and the level should continue to rise higher than projections earlier this year that did not account for the higher water flow from the snowpack. The amount of water flowing into Lake Powell is estimated at 177% of normal Colorado River flow. That “normal” also reflects the impact of the drought, as the average is determined by numbers over the past 30 years. The drought began 23 years ago.
In April, the Bureau of Reclamation released its updated 24-month study, which projected that Lake Mead would rise 22 feet above the level at that time — and 33 feet above projections that came out just a month earlier in March.
Measurements around the beginning of April put the estimated water content of the snowpack at 160% of normal levels, a welcome sign after years of severe drought.
As of noon on Friday, the surface of Lake Mead was at 1,051.30 feet above sea level.
Even with all the water during this above-average year, Lake Mead and Lake Powell are only projected to rise to 26% of capacity.
A wider satellite photo comparison shows a longer length of the river, but details are harder to see:
Rising water temperatures along the Colorado River over the past years have contributed to smallmouth bass establishing populations below Glen Canyon Dam.
The high-flow experiment could disrupt the spread of smallmouth bass, a non-native predatory species.
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