On April 16, 2019, President Donald Trump signed legislation directing the Secretary of the Interior to operate the Colorado River system in accordance with the Drought Contingency Plan agreements (“DCP”) approved by the seven states in the Colorado River basin. DCP is the latest addition to an extensive body of compacts, treaties, statutes, court decisions, rules, and agreements referred to as the “Law of the River,” which collectively govern our use of water from the Colorado River. In the Lower Basin (Arizona, California, and Nevada), DCP acts as an overlay on shortage sharing guidelines adopted in 2007 (referred to as the “2007 Guidelines”) and requires the states to take less water from the Colorado River in years during which the water level in Lake Mead falls below certain elevations. The 2007 Guidelines and DCP are intended to address declining water levels in Lake Mead and Lake Powell due to drought conditions in the Colorado River basin that now have persisted for 19 years, leading to conditions in which the amount of water used by the basin states and Mexico consistently exceeds the amount of runoff that enters the system on an annual basis. The water cuts required by DCP fall disproportionately on Central Arizona Project (“CAP”) water users due to a compromise deemed necessary to get congressional approval for the 1968 legislation that authorized the construction of CAP, which generally states that CAP will take shortages PG. 34 :: SUMMER 2019
before other existing users in the Lower Basin. Within the CAP system, agricultural contractors have the lowest priority. The 2007 Guidelines and DCP require Arizona to leave in Lake Mead 512,000 acre-feet of its 2.8 million acre-foot Colorado River entitlement in years during which the water level in Lake Mead falls below 1075 feet and a “Tier 1” shortage is declared. The end result is that, immediately upon the occurrence of the first level of shortage, the entire CAP agricultural water supply will be eliminated. Central Arizona’s abundant sunshine, reliably warm weather, and infrequent rainfall create ideal conditions for a yearround growing season and high crop yields, so long as sufficient water is available for irrigation. Despite urbanization throughout central Arizona, Pinal County, sandwiched between the Phoenix and Tucson metropolitan
areas, remains an agricultural powerhouse. According to a December 2018 study prepared by the University of Arizona Cooperative Extension, Pinal County ranks in the top 2% of all U.S. counties in total agricultural sales, and ranks in the top 1% of all U.S. counties in cotton and cottonseed sales, milk sales, and cattle and calves. That study also showed that Pinal County agriculture punches above its weight in feeding residents in the surrounding metro areas, and contributed $2.3 billion in total sales to the county economy as of 2016. CAP water constitutes a substantial portion of the irrigation water supply for central Arizona agriculture. Although Pinal County farmers historically relied primarily on groundwater pumped from private wells to irrigate individual farms, after the authorization of CAP, they formed irrigation districts and constructed modern, regional distribution systems designed specifically to distribute Colorado River water. Those farmers have continued to build on the efficiencies gained by constructing those distribution systems by adopting new irrigation and farming practices, and now have some of the most efficient irrigated agricultural systems in the west. Unfortunately, because those systems were designed to use Colorado River water from CAP, the abrupt loss of those water supplies during a shortage under DCP likely would take out of production 60% or more of the existing farmland in the irrigation districts immediately.
