The Republic | azcentral.com

Arizona is into the second decade of drought. A visit to Lake Mead is sobering. Conversations are starting about where the state will get water in the future.

We asked two experts: What if the drought continues for another 10 years?

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WATER WILL FLOW, GROWTH WILL STOP

Let's assume things continue pretty much like they have for the last decade, but don't get markedly worse. Here's the scenario:

Arizona's forests will be in serious decline. Beetle infestations and fires could eliminate huge swaths of Ponderosa pines. Some rural areas around the state will likely need to adopt growth moratoria, curtailing new development.

Closer to Phoenix, a couple of the Salt River Project reservoirs could be functionally empty, with deference to keeping the ones closer to the metro area as full as possible. Mead and Powell lakes would be at critical levels, with shortage sharing criteria in effect.

Central Arizona Project deliveries would likely be curtailed by something like 25 percent, with that cut coming out of agricultural use, resulting in dramatic declines in crops in Maricopa and Pinal counties. There will be deals to move water from the Yuma area to central Arizona.

Cities would likely impose limits on when lawns can be watered, and when cars can be washed. Grass might be prohibited in front yards in all new subdivisions. Golf courses will disappear (that's happening anyway from decreased demand). Groundwater pumping will increase, especially recovery of some stored water from the last decade.

Water will still come out of the tap. The Sun Corridor will continue to grow in population. And we'll be in better shape than San Diego, or Los Angeles, or Las Vegas.

Grady Gammage Jr. is a lawyer and senior fellow at ASU's Morrison Institute.

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SAY GOODBYE TO LAKES, HYDROPOWER

If the current 15-year drought on the Colorado River continues for another decade, it will rival the "mega-droughts" that appear in tree-ring records. There are two ways that this could play out for Arizona and the Colorado River Basin.

In one future, Lake Mead and Lake Powell are both dangerously low. Colorado River water deliveries are effectively reduced to whatever system runoff is available each year. Hydropower generation for the Southwest is minimal or non-existent due to low reservoir levels.

The Secretary of the Interior has intervened to prevent local catastrophes and avoid a system collapse, imposing massive water delivery reductions in the Lower Basin and, in the process, discarding the priority system that had governed the river. As a result, the basin states and major water users are embroiled in litigation that will not be resolved by the U.S. Supreme Court for decades.

In an alternative future, proactive measures implemented by the basin states and water users to reduce water use, curb losses and augment river supplies have been effective in preventing excessive reservoir declines, despite the continuing drought. Water deliveries and hydropower generation are stable and predictable. The Law of the River remains intact.

The Central Arizona Project is working hard to make this second future a reality, but we can't do it alone. It will take concerted action by all Colorado River water users and the United States to ensure the sustainability of this vital resource.

Pamela Pickard is Central Arizona Project's board president.