The Central Arizona Water Conservation District (“CAWCD”) and the Yuma Mesa Irrigation and Drainage District (“YMIDD”) are undertaking a pilot fallowing and forbearance project, which will conserve a supply of water that will remain in the Colorado River system.
The pilot project covers a six-year period—from January 1, 2014 through December 31, 2019—which is broken into two 3-year periods. Any lands enrolled in the program can be fallowed for no more than three consecutive years—and there is a cap on fallowing of up to 1,500 acres per year.
A 2008-2010 demonstration program that YMIDD participated in with the Bureau of Reclamation showed a savings of 7 AF/acre, but further analysis revealed the actual savings to be 5 AF/acre, which is consistent with fallowing programs on the mainstem Colorado River in California.
The annual enrollment payment that CAWCD pays to YMIDD is $750/acre ($150/AF, based on 5 AF/acre), escalated annually by CPI-U, subject to a minimum of 2% and a maximum of 6%. The annual enrollment payment for 2015 was $765/acre ($153/AF)—which is a 2% increase from the 2014 payment. In addition, CAWCD is compensating YMIDD for its increased administrative costs with a payment of $10,000 per year and is paying $23.36/acre (approximately $4.67/AF) to reimburse for lost revenue from non-use of excess water.
With fallowing of 1,500 acres per year and a water savings of 5AF/acre, the total annual water savings would be 7,500 AF per year. When the project was first announced the estimated annual water savings was about 9,000 AF per year.
The water will be retained in the Colorado River system and will count towards the CAWCD’s 345,000 AF of extraordinary conservation under the December 2014 Lower Basin MOU (see “Lower Basin States Sign MOU to Stave off Shortage,” JOW, January 2015). However, the purpose of the pilot project is gather information to inform decisions about a longer term project to meet Central Arizona Groundwater Replenishment District’s (“CAGRD”) water supply needs while protecting and enhancing agricultural production YMIDD and the Yuma area.
“As we look to identify creative ways of reducing or delaying shortages along the Colorado River, this pilot program will provide critical information to all of us who depend on the river as our most important renewable water supply,” said CAWCD Board President Pamela Pickard.
Written by Marta L. Weismann
 CAGRD is the department of the CAWCD that is responsible for CAWCD’s replenishment authorities.