Categorized | Climate Change, In the Field

Lake Mead at Record Low

Lake Mead. Photo: NASA

Media outlets across the West are reporting on the record low elevations at Lake Mead on the Colorado River.  This being the 75th anniversary of Hoover Dam, now is a good time to look at the past, present and future of not just the dam, but the entire Colorado River.

On October 17th, Lake Mead dropped to 1,083.18 feet above sea level; today, Lake Mead is at 1,082.25 feet elevation – the reservoir hasn’t been this low since it was first filling in the 1930s.  And it continues to drop.  We are not only witnessing the lowest that Lake Mead has been since 1937 but also the lowest 11-year average of inflows in the last 100 years.

The Colorado River basin is deep in drought.  Increased consumption, an unhealthy watershed and climate change all play a part in this precipitous drop.  When the river was divvied up in 1922, they thought it had an annual flow of about 16.4 million acre-feet, while the past 100 years have shown us it’s more like 15.1 million acre-feet.  Analysis of tree rings indicate that annual flow – measured over millenia – may be anywhere from 13.4 to 14.7 million acre-feet.  To make matters worse, researchers are learning that climate change will make that number even smaller — 5% to 20% smaller by 2050.

These lows have dire consequences for wildlife.  The filling of Lake Mead in the 1930s, and again in the 1960s in anticipation of the completion of Glen Canyon Dam, turned the river into a trickle that rarely reaches the Gulf of California.  The Colorado River delta once covered nearly 2 million acres of riparian-wetland habitat, which supported over 400 species of plants and animals.  Since then, marine life like the vaquita and totoaba virtually disappeared and Delta wetlands shrunk to one-fifth their former size.  Fish that were once common are now endangered.

There is danger that another historic low in Lake Mead elevation will again devastate wildlife and rural communities, this time in the Great Basin.  Should Lake Mead hit 1,075 feet elevation, Las Vegas will put even more pressure on the scarce water resources, as it seeks to develop a $3 billion project that would export groundwater that sustains hundreds of seeps, springs and streams in the Great Basin to try to sustain instead its own growth.  We should learn a lesson from the impacts to fish, wildlife and native communities in the Delta: rather than take water that already supports national wildlife refuges, national parks, state wildlife areas and rural communities, let’s look to water conservation and more responsible solutions.

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- who has written 2 posts on dotWild.

Kara Gillon is a senior staff attorney at Defenders of Wildlife. Kara works on a variety of state and national Endangered Species Act, National Environmental Policy Act, and other environmental regulatory and litigation activities.

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One Response to “Lake Mead at Record Low”

  1. Sara O'Brien says:

    Scary stuff, makes me glad I moved out of Tucson. I just finished James Lawrence Powell’s book, Dead Pool — have you read it?


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dotWild is the blog of scientists and policy experts at Defenders of Wildlife, a national, nonprofit membership organization dedicated to the protection of all native animals and plants in their natural communities.