Since its inception over a century ago, IID and its growers have implemented ambitious conservation programs and efforts that include concrete-lined canals and head ditches to reduce seepage, delivery system automation, regulating reservoirs, scientific irrigation scheduling, tailwater recovery systems, sprinkler irrigation, drip irrigation and land leveling.
Additional significant conservation practices have been in place for more than 25 years after the district and the Metropolitan Water District of Southern California entered into its landmark water conservation agreement in 1988. The various conservation methods have saved millions of acre-feet for Southern California’s urban water use since inception.
In doing its part today to help California live within the state’s basic 4.4 million acre-foot apportionment of Colorado River water, IID is the primary implementer of the Quantification Settlement Agreement – the nation’s largest ag-to-urban water conservation and transfer project.
Under the QSA, water conservation efforts at IID include temporary land fallowing, and a conversion to both system and on-farm conservation efforts that steadily ramp up annually until leveling off in 2026.
A System of Water Apportionment
Since 2013, IID has been implementing a system of apportionment to help agricultural water users more accurately plan and manage their annual water use. Under IID’s Equitable Distribution Plan, the district offers an apportionment volume, equivalent to a water budget, at the start of the year to each farm unit. The apportionment is determined using a hybrid calculation comprised of half of a field’s historical average annual water use and a straightline, acre-foot-per-acre value.
Agricultural water users are encouraged to closely plan their yearly cropping plans and irrigation schedules to maximize their apportionments. The district provides support to growers who seek assistance in creating crop water budgets and measurement tools to monitor their field water use throughout the year.
Further, in cooperation with the ag community, the district established an Agricultural Water Clearinghouse to provide a method for free water transfers between farm units. This allows a farm unit that has more apportionment than is needed for its cropping mix to offer excess water through the clearinghouse to farm units that may need additional water to finish a crop.
Fallowing is the practice of temporarily taking active farmland out of production. Water, which under normal circumstances would have gone to the land to produce crops, is considered conserved under the fallowing program. Conserved water from fallowing is transferred to the San Diego County Water Authority, used for delivery to the Salton Sea (through 2017) to mitigate the environmental impacts of these transfers, and for payback or storage purposes. The water transfer schedules call for the district to generate 150,000 acre-feet per year through fallowing from 2013 through 2017 for these mitigation and transfer needs, after which IID’s required fallowing will be completed. In 2014, the fallowing program was re-engineered to better integrate it with the farm unit approach developed for the district’s Equitable Distribution Plan.
IID also generates conserved water to meet the needs of the QSA water transfers by making water efficiency improvements in its delivery system. Conservation targets started at 4,000 acre-feet in 2008 with the goal of capturing and reusing operational discharge. With the completion of the first system conservation project (the Main Canal Seepage Interception project and other system projects), the district conserved nearly 45,000 acre-feet in 2015 through system conservation. IID system conservation measures are expected to generate nearly 50,000 acre-feet in 2016, with the goal of reaching 103,000 acre-feet annually in 2026. System conservation efforts improve the reliability and flexibility of water deliveries and facilitate future on-farm conservation efforts. Components of the System Conservation Program:
• major integrated information management systems
• communication upgrades
• installation of automated headings
• monitoring of system operational discharge
• a pilot delivery measurement project on two zanjero runs that will be scaled up district-wide
• notebook computers for zanjeros
• reservoirs and interties
On-Farm Efficiency Conservation Program
Of the 303,000 acre-feet of conserved water IID needs to generate for the QSA water transfers at full implementation, 200,000 acre-feet is to come from on-farm conservation measures by 2026. In 2015, IID generated 85,628 acre-feet through on-farm water conservation measures.
Under this program, voluntary water efficiency improvement projects and conservation measures are implemented as contracts are made between the district and ag water users. The program pays participants $285 per acre-foot of delivered water reduction, which is verified against historical deliveries specific to each field and crop.
The All-American Canal Lining Project
IID provides 67,700 acre-feet of conserved water annually to Southern California through the All-American Canal Lining Project.
• 11,500 acre-feet goes to the San Luis Rey Indian settlement parties
• 56,200 acre-feet goes to the SDCWA
Considered to be one of the largest civil engineering efforts in the country at the time, the canal lining project consisted of constructing a parallel canal, 23-miles in length, emerging about 20 miles west of Yuma, Ariz., and extending to IID’s Drop 3 hydroelectric facility.
IID-MWD Water Conservation Agreement
IID conserves 105,000 acre-feet annually for the Metropolitan Water District of Southern California through the historic water transfer agreement entered into by the parties in 1988. Not to be confused with IID’s more recent System Conservation Plan, for nearly three decades MWD has been funding capital and annual operating and maintenance costs for specific water conservation projects in the IID water delivery system in exchange for the conserved water generated by the projects. Water conservation measures include:
• Canal lining projects
• Lateral interceptors
• 12-hour deliveries
• Non-leak gates
• Irrigation management
• System automation
As the QSA’s primary implementing agency, IID invests its interests in the Salton Sea Restoration and Renewable Energy Initiative as a solution to preserve the long-term viability of the water conservation and transfer pact among California’s Colorado River water users.
Under the Salton Sea initiative, IID seeks to integrate the resolution of Salton Sea environmental and public health impacts from the QSA water transfers with the development of renewable energy assets in the region to create a beneficial water-energy nexus.
Additionally, IID’s petition to the California State Water Resources Control Board similarly requests the state live up to the Salton Sea restoration obligations it committed to in 2003 in order to ensure the long-term viability of the various conservation and transfer programs that provide water supply reliability to Southern California. IID and its partners believe that a smaller, but sustainable, Salton Sea restoration plan is viable and will, over the long-term, proactively address transfer-related environmental concerns while reducing long-term mitigation costs and public health impacts.