Audacious Water
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Audacious Water

Sarah Porter: Shortage (and Abundance) as the New Normal

Credit: Kevin Spencer

By Sarah Porter, director, Kyl Center for Water Policy at Morrison Institute

Central and southern parts of Arizona may have to adjust to receiving significantly lower levels of water from a project that has played a central role in fueling economic and population growth in these regions for nearly 35 years.

But does this news necessarily have implications for Arizona’s future growth? Or can we shift to a new paradigm that relies on ingenuity and decoupling growth from water demand?

The Central Arizona Project and Arizona’s Growth

First, some background. Lake Mead, the massive reservoir that provides Colorado River supplies to Arizona, California, Nevada and Mexico, has been declining as a result of prolonged drought and over-allocation. The three states and Mexico have worked out an agreement, called the Lower Basin Drought Contingency Plan (DCP), to take voluntary cuts to shore up lake levels. The agreement also establishes ground-rules to facilitate voluntary conservation of water supplies in the reservoir.

Colorado River supplies delivered to the Phoenix area, Pinal County and greater Tucson via the 336-mile long Central Arizona Project (CAP) canal have supported economic development and population growth since the first CAP delivery was made back in 1985. Indeed, today, CAP water comprises about 40 percent of the Valley’s water supply.

But CAP users have junior priority on Lake Mead, so they are first in line to take cuts. Farmers in Pinal County stand to be most impacted, but deeper cuts could impact tribes and cities and towns. After months of difficult negotiations, Arizona stakeholders have worked out a complex set of deals to mitigate the effects of those cuts with a combination of funding and water from other sources. With the deal inked on January 31s, the state enacted legislation authorizing Arizona’s participation in the Lower Basin DCP.

Arizona After the CAP Cuts: The Short- and Long-Term Outlook

What does all this mean for Arizona? In the short run, if Colorado River supplies are reduced, farmers in Pinal County will return to pumping groundwater to irrigate their crops. Because Central Arizona receives relatively little precipitation, the water these farmers withdraw will probably not be replenished, and the area will be extra challenged to find water for future demand.

Groundwater overdraft was a serious problem for central and southern Arizona back in the 1960s and 70s — the CAP was foremost a “rescue” project to address groundwater mining. So for some water planners, Pinal County’s return to heavy use of non-replenishing groundwater feels like a step backward. For the farmers and others who stand to take the biggest cuts, groundwater pumping is the only viable alternative to severely reducing production — and possibly going out of business.

In the long run, central and southern Arizona will likely have to adjust to reduced CAP supplies. For the most part, municipal water providers have reckoned with this eventuality and have secured supplies to avoid dramatic water rationing scenarios. In older cities, large, diverse water portfolios and their population’s gradual adoption of water efficient technologies and low-water landscaping mean that current water supplies can be stretched to meet some or all new demand. But some newer urban areas have yet to secure water supplies for their future growth. Obtaining that water may be a major challenge for these communities.

‘Shortage as the New Normal’: Why I’m Optimistic about Arizona’s Ability to Adjust

Three things make me optimistic about central and southern Arizona cities’ capacity to adjust to the prospect of “shortage as the new normal” vis-à-vis CAP supplies:

  • First, as a part of the intrastate DCP deal, the Gila River Indian Community has made a large supply of water available to support some 30 years of urban growth.
  • Second, there is still “give” in the system; that is, there remain opportunities for voluntary re-allocations of water (for example, from agricultural use to urban).
  • Third, over the last two decades, population and economic growth have become “decoupled” from water demand — meaning that we can add people and economic activity without a correlated increase in demand.

That decoupling is largely the result of advances in technology, water management and water policy. In working to change the water narrative from one of scarcity to abundance and opportunity, ASU’s Future H2O can play an important role in ensuring that Arizona, the West and other water scarce parts of the world stay water resilient.



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