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By Jaweed Kaleem , Thomas Curwen. Photography by Allen J. Eric Richins, owner of Big Water Boating, surveys water levels and fish on Lake Mead, where he has led tours for two years. Eric Richins studies the water at the Temple Bar Marina entrance to Lake Mead to see if he can safely launch his pontoon boat.
A boat cruises at sunset in front of a formerly sunken bench near Hemenway Harbor. Kayakers make their way through a shallow stretch of Lake Mead by the now-closed Boulder Harbor boat ramp. Patti Aaron, a spokeswoman for the U. Bureau of Reclamation, tours the outflow area at the bottom of Hoover Dam, where water is released back into the Colorado River. Lightning strikes over Lake Mead as a storm rolls through. The lake is the largest reservoir in the U.
Because of declining water levels, desert bighorn sheep have more land to roam near Lake Mead. The fate of Lake Mead really was sealed in , well in advance of its existence, with the drafting of a seven-state compact governing distribution of the waters of the Colorado River.
Construction of the dam and the filling of Lake Mead helped fuel epic population growth in the Colorado River basin, especially in California. One acre-foot equals about , gallons, enough to serve one or two average California households. The lake last peaked at more than 1, feet above sea level in The 20th century was consumed with that, and it was fraught with enormous expense, delays and bad will.
For the last 20 years, the states have recognized that coordination and cooperation are much better than litigation. But coordination and cooperation are easier said than done.
The supply and usage of water in the West is a vast web in which plucking on any strand sends vibrations across the region. The claimants of Colorado River water include states, irrigation districts, tribes, farmers and urban dwellers, all of whom have conflicting interests and water rights.
Overseeing them all, at least theoretically, is the federal government, which built Hoover Dam and still has ultimate jurisdiction over the reservoir through the Bureau of Reclamation. Arizona faces the harshest and nearest-term cuts, in part due to agreements dating from the s that allowed it to build the Central Arizona Project, a huge aqueduct for its agricultural users.
California retains its water rights the longest — its annual apportionment of 4. At that point the state has to start giving up some of its Colorado River water. That placed a premium on reconsidering the interim guidelines to make them consistent with the greater risk.
The federal government has been applying intense pressure on the basin states and their water users to reach a final drought contingency plan. Reclamation Commissioner Brenda Burman fired a shot across their bows on Feb. Six years ago, at the end of the summer of , federal Bureau of Reclamation officials worried that Hoover Dam, the biggest hydropower enterprise in the Southwest, might soon go dark.
Today, the story has a twist. Lake Mead is 10 feet lower, a new record set on May 18 that is re-broken every day now. Dam operators are revising the lower limit to feet, a boundary that will be confirmed in October once the fifth and final more-efficient turbine is installed, Davis said.
The investments in wide-head turbines, stainless steel wicket gates, and digital controls are emblematic of the types of practices that are necessary for the drying Colorado River Basin.
In order to maximize scarce water, authorities must do more with less. Dam managers and power customers are adopting the same ethic for power generation. Electricity from Hoover is some of the cheapest in the country, at 1. Constructions costs for the dam were paid off years ago and the energy source, the water, comes from Mother Nature free of charge.
Maximum amount of power that the dam is capable of producing — is down 30 percent from when Mead was full. For every foot that Mead drops, generating capacity decreases by five to six megawatts. Money is power, the old saying goes. So is water. Pressure differences in the water coming into the generators produce air bubbles on the turbine blades. As the water flows across the blades, the bubbles collapse and burst, which causes vibrations that can damage the generating unit.
If the vibrations worsen, the unit must be shut down. The wicket gates, on the other hand, allow for more precise control of water flowing through the turbines. They also reduce water leakage so that every drop that passes through Hoover can generate as much power as possible.
That will still be painful, particularly for metro Phoenix cities that use NIA water to serve a few existing customers. The May projection is already within about 3 feet of reaching a Tier 2b shortage. Not the best or worst case, but the most likely. If the lake is projected to fall below 1, feet any time within two years, Arizona, California and Nevada must reconvene to decide what additional steps they will take to keep Mead from falling below 1, feet — an elevation that many consider the crash point.
And that provision is triggered by any part of the forecast — not just the maximum or most probable scenario, but the minimum probable scenario, too.
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