by David A. Schaller
What Is The Drought Contingency Plan?
In March of this year, Arizona joined six other states and signed a 60-page management plan specifying how Colorado River water shortages will be shared ahead of and after an anticipated shortage declaration on Lake Mead. To reach this point, each of the seven states developed its own Drought Contingency Plan (DCP), committing to specific steps it would take to either keep upper-basin water in Lake Powell or lower-basin water in Lake Mead. These state DCPs were then bundled into an overall agreement and enshrined in federal law, enabling Interior Department water managers to execute a number of individual agreements, transactions, exchanges and other operational measures necessary to meet water cutback targets agreed to by the states.
Some closest to the Arizona DCP negotiations see it as more than a “Drought Plan.” Dan M. Offret, a board member with the Metropolitan Domestic Water Improvement District (Metro Water) in Pima County, was closely involved in the DCP’s negotiations. He sees the agreement as “not so much a drought plan as a crisis avoidance plan without federal direction… the DCP shows that this entire river basin has acted in a spirit of cooperation rather than confrontation,” which has not always been part of the historical record when it comes to Colorado River water conversations, says Offret.
Where The Central Arizona Project Comes In
The Arizona DCP and the supporting network of other states’ plans were necessary to prevent the water level in Lake Mead from dropping to a level that would trigger immediate, deep, and mandatory curtailments to Arizona water users dependent on Colorado River water delivered through the Central Arizona Project (CAP).
To forestall this as long as possible, Arizona, along with the other lower-basin states, agreed to keep more water in Lake Mead now to prevent more damaging cutbacks later. For Arizona, even with the DCP, there remains an odds-on chance that a shortage will be declared as early as next year should water levels drop below important trigger points. In that event, Arizona would lose as much as half a million acre-feet of water a year.
The Impact Of A Potential Water Cutbacks
Much of the inconvenience involved with Colorado River cutbacks depends on whether alternative sources of water are legally available and accessible, and to whom. Those with high-priority water rights like the Colorado River and Gila Indian communities are making water available, for a price, of course, to lower-priority users such as Pinal County farmers. But this is just a short-term fix until the farmers can upgrade the infrastructure to resume large-scale groundwater pumping as they did before Lake Mead began dropping in earnest. Even so, Pinal farmers expect to fallow almost 40 percent of their acreage in the years ahead.
As a second round of groundwater extraction proceeds, we have the benefit of knowing what it looked like the first time around. Near Eloy, several decades of massive groundwater extraction to irrigate thirsty fields of cotton have opened about 70 miles of deep earth fissures, according to the Arizona Geological Survey. The survey adds that the valley floor around Eloy has subsided as much as 20 feet in the past 50 to 60 years, while water tables once tens of feet from the surface are now hundreds of feet deep. The state’s Water Agency says soil compaction during subsidence now limits aquifer recharge. Thus, subsidence will continue to expand the labyrinth of deep crevasses in the county. Says a state spokeswoman, the subsidence “is permanent and irreversible.”
Groundwater For Crops
Meanwhile, the crops that will be grown in Pinal County are often destined for other shores. Cotton is shipped to Bangladesh, while alfalfa and other forage crops are sent to Asia and the Middle East. Whether we think of it this way or not, we are permanently exporting our groundwater every growing season, bushel by bushel and bale by bale.
Massive groundwater pumping is continuing all over the Colorado River basin. While we have focused on water levels in Lake Mead, data from two NASA satellites indicate that between 2004 and 2013 the groundwater pumped from beneath the seven basin states was a volume equivalent to one-and-a-half Lake Meads.
Taking Action Now To Prevent Permanent “Drought” Conditions
Water managers and government officials refer to the entire exercise of propping up Lake Mead as a “drought” contingency effort. But what if our current 19-year period of dryness becomes more than a drought? What if the dryness we call drought remains a permanent condition, one that redefines what we expect from year to year, decade to decade?
This is what we may be facing as our current drought threatens to become a permanent state of aridness, where annual patterns of temperature and rainfall are no longer valid for water planning purposes. How can we know what a permanent “drought plan” should consider if we don’t yet understand what “normal” conditions look like? In some ways, this explains why the 2007 Colorado River agreement needed a mid-course correction right now in the form of the new DCP.
And what of the loss of river and reservoir water as the drought becomes more severe? Data show that evaporation from Lake Powell and Lake Mead subtract an estimated one million acre-feet of Colorado River water annually. Do our DCPs adequately account for the loss of this million acre-feet? We’ll find out.
Timing Is Everything
The good news is that Arizona is fresh from a difficult round of negotiations. There is no better time than now, before deep rationing kicks in, to get serious about our water future.
The takeaway point from the DCP is that, voluntary or otherwise, rationing of Colorado River water is underway. The test of the DCP will be whether it helps keep Lake Mead above shortage thresholds long enough for a more permanent Colorado River allocation and management plan to be crafted by 2026. We must hope that it does.
David Schaller is a retired environmental scientist living in Tucson, where he writes on climate, water, and energy security.
Photo credit David Schaller