Arizona Irrigation District Tries Land Fallowing Water Transfer
by Lucero Radonic, WRRC Graduate Outreach Assistant
In January 2014, Arizona will begin its first farmland fallowing and forbearance project. Unlike similar fallowing programs in the West, this project does not transfer the water conserved in the agricultural sector to the municipal sector. For the time being, this program seeks to conserve water in the Colorado River system. The saved water will be maintained in Lake Mead, increasing its dwindling levels and helping forestall shortages to water users in the Lower Colorado River Basin. Since 2000, water levels in Lake Mead have fallen by an alarming 100 feet. If the lake’s elevation falls by another 30 feet, users in the lower basin would face reductions in water allocations.
According to a 2006 article by UA professor Bonnie G. Colby and colleagues, the rationale for encouraging fallowing as a conservation measure is that an estimated 20,000 to 60,000 acre-feet of Colorado River water could be saved through forbearance of a small fraction (4 to 11 percent) of water allocated for agricultural irrigation in California and Arizona.
Arizona’s new three-year project was agreed upon by the Yuma Mesa Irrigation and Drainage District (YMIDD) and the Central Arizona Groundwater Replenishment District (CAGRD). Per the agreement, volunteer farmers will be paid not to grow crops and, thus, the district will not divert Colorado River water that otherwise would be used to irrigate the fallowed lands. Known as “America’s Winter Vegetable Capital,” the Yuma Valley has more than 50,000 acres of farmland and uses approximately 370,000 acre-feet of Colorado River water per year. With mild winter temperatures and plenty of sunshine, Yuma County has the longest growing season in the country, making it the source of 90 percent of all leafy vegetables produced from November through March in the United States. But with less than three inches of rain per year, to make this possible, water needs to be brought into the area from the Colorado River. Praised as an engineering marvel when it was completed in 1912, the underground Yuma Siphon continues to deliver Colorado River water to the Yuma Valley. Today, Yuma’s agriculture industry represents more than one-third of Arizona’s annual gross economic returns from Agriculture.
Through the fallowing program, CAGRD seeks to fallow a maximum of 1,500 acres of land per year in the YMIDD. This is less than 10 percent of the district’s total irrigated surface area, which is dedicated to growing mostly citrus, lettuce, cotton, alfalfa and wheat. To accomplish this goal, CAGRD will pay volunteering farmers a base rate of $750 per acre of fallowed land. In order to qualify, the land to be fallowed has to receive water from the Colorado River. It must have produced irrigated crops in four of the last five years and must total a minimum of five contiguous acres. In addition, no one landowner can put more than 18 percent of his or her land into the program. Program guidelines also stipulate that participating landowners must control weeds and dust on their fallowed land and maintain the ditch structures within the privately owned irrigation system so to avoid prejudice to downstream users. Participants must also continue paying the district assessments on their land.
If the program is extended beyond three years, landowners can remain in the program, but they must fallow a different sector of their property. Enrolled land cannot be permanently taken out of agricultural usage during the time of the agreement. Also, property owners cannot sell the land for residential development, as has been common for many years. In the last decade, about 5,000 acres of farmland in the YMID have been converted into tracts of suburban housing.
As stipulated by state law, CAGRD is obliged to replenish groundwater in an amount equal to the replenishment obligations of its members, i.e., subdivisions, cities, towns or water companies in Pima, Pinal or Maricopa counties. The CAGRD is actively seeking new sources of water supply to meet its replenishment obligation. The fallowing project is the glimmer of a supply acquisition strategy for groundwater replenishment. The notion is controversial and if the project is a success, fallowing may gain support among skeptics.
Cropland fallowing is neither a new concept nor an uncommon practice in the agricultural world. In arid climates, farmers regularly fallow lands for one season to conserve soil moisture and nutrients for a subsequent growing season. Letting land fallow for extended periods rebalances soil nutrients, re-establishes soil biota, accumulates soil moisture, and breaks crop pest and disease cycles (see companion fallowing study article, this issue). However, fallowing land means foregoing crop production and, hence, income from that land.
Supporters of fallowing agreements like the one undertaken by YMIDD present it as a win-win process. From the municipal water manager’s perspective, this approach reduces water extraction and is a cheaper alternative than converting salty water into potable supplies or building new pipelines to bring water from distant sources. Farmers are said to benefit from a guaranteed paycheck and soil regeneration in their fallowed fields. The district views the agreement as a strategy for prolonging citrus growth by rejuvenating the soils, providing revenues for farmers to replant old citrus trees, ensuring long-term water availability, and fostering friendly relationships between farmers and other conservation-minded stakeholders.
Critics of fallowing programs argue that they have a negative impact on the local agriculture-based economy. Businesses will see a reduction in demand for their goods and services. If closures result, remaining farms may experience difficulty obtaining the goods and services they need to remain productive, and rural communities will be harmed. In addition, these agreements are viewed by some as a slippery slope toward transfers of agricultural water rights to cities.
Over the last decade, fallowing agreements have become popular across the West as a strategy for adjusting to decreasing water supplies in stressed river basins. In Southern California they have been particularly popular. They have also been controversial for redirecting agricultural water to the municipal sector. In 2003, the Imperial Irrigation District and San Diego County Water Authority entered into a 45-year water transfer agreement establishing that the San Diego region would receive up to 200,000 acre-feet of water per year from the irrigation district. Fallowing is listed as a permitted method for saving water only for the first 15 years; afterward, the district must have efficiency-based conservation measures in place to produce the water. Similarly, in 2004 the Palo Verde Irrigation District and the Metropolitan Water District signed a 35-year agreement to allow for agricultural-to-urban water transfers in the area. Per the agreement, in any year Palo Verde farmers fallow between 7 and 28 percent of their lands at the request of the Metropolitan Water District, making saved irrigation water available to urban Southern California.
A much smaller pilot fallowing project was undertaken in 2009-2010 by the U.S. Bureau of Reclamation in Arizona. Because of the small scale of the project, it was not possible to quantify how much Colorado River water could be saved by leaving fields idle for a season. The three-year agreement between YMIDD and the CAGRD is intended in part to help determine the actual amount of water to be conserved through rotational fallowing. It is estimated that the program will result in water savings of about 9,000 acre-feet per year. While this is a relatively small quantity, it represents a significant step when considering the alarming water levels to which Lake Mead has fallen since 2000.