IID water conservation program attempts to limit waste
EL CENTRO — When it comes to water, arguably the most important resource in the Imperial Valley, conservation is essential to the long-term success of the local farming community and to area residents.
The Imperial Irrigation District, the fourth-largest irrigation district in the nation, is responsible for delivering water to about 500,000 acres of farmland.
IID manages the largest gravity-fed irrigation system in the Western Hemisphere, delivering Colorado River water — via the All-American Canal — for agricultural, urban, industrial, environmental and recreational use.
More than 95 percent of water delivered in the IID service area goes to support agriculture. With a 3.1 million acre-feet annual entitlement to Colorado River water — the only source of fresh water in the Valley — IID must be a careful steward of every drop flowing through its 1,668 miles of delivery canals.
And, since 2003, IID is mandated to deliver a large quantity of water to the San Diego County Water Authority as part of the Quantification Settlement Agreement.
To ensure IID is meeting its obligations under the QSA and maintaining enough water for local use, IID has aggressively been conserving water to meet increasing QSA allotments each year since 2003.
Conservation efforts generated more than 314,000 acre-feet in 2016 for the QSA, in addition to the 105,000 acre-feet generated annually by the conservation program funded by the Metropolitan Water District of Southern California and the 67,700 acre-feet conserved by the All-American Canal Lining Project.
Collectively, with all its conservation efforts, IID will ultimately conserve about 15 percent of its consumptive use entitlement each year — more than 487,000 acre-feet — when all conservation measures are at full implementation.
One acre-foot equals about 326,000 gallons, or enough water to cover an acre of land, about the size of a football field, 1-foot deep, according to watereducation.org.
An average California household uses between 0.5 and 1 acre-foot of water per year for indoor and outdoor use.
Meeting obligations
Through the IID’s System Conservation Program, the district is achieving portions of its contractual obligations for conserved water under the QSA from a suite of new system projects and structural upgrades to the district’s main canal systems.
Components of the System Conservation Program are the discharge reduction program, communication upgrades, installation of automated lateral headings, 7design and installation of monitored discharge sites, addition of laptop computers to monitor real-time water flow in IID field trucks, system control and data acquisition integration and monitoring, large operational reservoirs, mid-lateral offline operational reservoirs, existing operational reservoir upgrades, main canal and lateral interties, and main canal seepage recovery projects.
System efficiency conservation specific to the seepage recovery efforts in 2017 generated 64,583 acre-feet of water with more projected in future years as programs ramp up.
When all conservation projects are included, not just seepage recovery efforts, IID has generated 4.7 million acre-feet in conserved water since 2003 and ended the 2017 water year conserving 80,937 acre-feet.
Seepage recovery projects
Along earthen-lined canals, water tends to seep into the surrounding soil. In addition to being a loss, the excess water can actually damage crop production in nearby fields. When there is too much water in the soil, crops such as alfalfa tend to die from rotted roots.
To address this issue, IID has implemented a series of measures to recover water lost through seepage — collecting it in seepage recovery sites and pumping it back into the main canals for redistribution. Much of the infrastructure put into place is near the East Highline Main Canal east of Holtville, an area that has historically experienced a large amount of water loss through seepage.
During his shifts each week, Dylen Mohamed, IID water conservation data technician, can be found driving all over this eastern portion of the IID service area to ensure the right amount of water is flowing into and out of various seepage recovery sites.
“I basically do all the quality control on the data that comes in from the seepage recovery sites in addition to other system conservation projects that we have going on,” Mohamed told Imperial Valley Press during a tour Thursday morning. “That requires me to watch all the data coming in and verify what we are seeing is actually what is happening out here. I come out and double check that everything is looking right. I open up the boxes and make sure that everything that we are reading in the office — because we can see in real time — is actually what we are seeing out here and matches up.”
At the end of each month, Mohamed tabulates the amount of water that has flowed in his coverage area. That data is collected quarterly and annually and reported to the U.S. Bureau of Reclamation.
“We need to make sure that all the tabs we take and keep are accurate with what is coming in and what is going out, and we are only allotted so much water in the Valley from the Colorado River,” Mohamed said. “We keep accurate records on everything we do.”
The daily vigilance of Mohamed and his fellow IID employees to ensure all the water flowing in the system is measured accurately is an essential function, said Vince Brooke, IID general superintendent of the system conservation programs.
“We are doing this for the San Diego transfer, the QSA,” he said. “So, what we are doing by him bird-dogging this, as it is, we are maximizing the production of that water. If we didn’t pay attention to what is going on, then our production is down, and our efficiency is not as high. That is the main goal, but the accounting side is where we have internal folks who are sorting out our water usage, our water balance, and all this comes into play in that.”
Currently, IID is “running it at its peak efficiency,” Brooke said.
System upkeep
In addition to monitoring the flow of water at the sites, Mohamed also keeps an eye on issues that could be detrimental to the system, such as excess vegetation buildup in the collection ponds.
“I come out here and help keep up with the maintenance and bird dog with many different groups within the IID that we need to come out here and clean up any of the sites and keep the vegetation down,” he said.
Not all vegetation growth is bad, since some vegetation prevents the earthen walls from eroding, Brooke said during the tour.
“We’ve done a lot of trials and found that it doesn’t make a big difference if we spray or clean the whole big channel,” he said. “The water still moves through the reeds and it helps hold the embankments. It is habitat. So, we worry about [seepage recovery sites] and not too much about the channel itself.”
The system is built to ensure that only raw water is collected in the seepage recovery basins, and never runoff from nearby fields. Runoff is directed instead into a series of about 1,456 miles drain canals crisscrossing the Valley.
“We don’t want any runoff from the fields running back into this area,” Brooke said. “There could be fertilizer in it, there could be stuff they sprayed on the plants. We just don’t mix it. It is best to keep them separate. We can’t use drain water. We can reuse seepage recovery water.”
Automated pumps
Farther south on the East Highline Canal, Wayne Ragland, IID zanjero, on Thursday was monitoring automatic pumps that deliver water into various canals for delivery to fields downstream. The automatic pumps were installed to help IID conserve water.
The pumps, interconnected via a mobile computer network, can be controlled remotely via laptop computers in IID field vehicles.
“It has made it a lot easier for us, a lot easier to regulate,” Ragland said. “We no longer have to come from the bottom, about six miles away, all the way to the top to make adjustments. We can make it from there and save water sooner.”
The ability to change the flow without having to be present at the pump site saves several hours of commute time each day, Ragland said, although sometimes the pumps need to be manually adjusted for accuracy.
“As far as the headings, the accuracy [can be] a little off when you are out here,” he said. “You can see if you are short or high. Right now, it was going down Lateral 7 and I saw I needed a few more acrefeet. I actually could add more water while I was three quarters away down the canal.”
Brooke said there has been a bit of a learning curve for the new automated systems, but that the kinks are getting ironed out.
“If we know we are off a little bit, we can change the flow to match,” he said. “That is called recalibration. We have the ability to tune it.”
Future projects
In the future, reservoirs will be added to the system to help hold recovered seepage water throughout the Valley, Brooke said.
Currently, the IID Board of Directors is considering a proposed East Highline Reservoir design that will help IID meet its QSA requirements. The project is estimated to cost $1.75 million.
To assist in meeting these obligations, the water department has contracted with HDR to develop the design and bid package for a large above-ground operational reservoir in the southeast section of IID’s service area. If constructed, this project is anticipated to reduce operational discharge and facilitate operational flexibility for growers participating in the on-farm efficiency conservation program now that the Salton Sea mitigation deliveries have concluded.
In February 2017, the board authorized Major Work Authorization No. 200004 for the engineering design, bid process assistance and pre-construction development of the proposed reservoir with operational capacity of 2,500 to 3,400 acrefeet. On May 8, the board authorized Amendment No. 1 to make modifications to the original plans. These changes resulted in a scaled-down reservoir with 2,900 acre-feet of operational capacity, additional engineering modifications to the inlet/outlet and the development of final engineering designs and bid specifications for the solicitation of construction services in order to determine final project costs.
A decision to proceed with any specific site and construction of a Water Department facility will not take place until after IID has completed the environmental analysis required to comply with the California Environmental Quality Act. The preferred site and potential alternative sites are currently being analyzed as part of the CEQA compliance process, and future decisions will be subject to that analysis.