Irrigation districts investing in water conservation
by David Lester
Yakima Herald-Republic, September 29, 2010
GRANDVIEW -- On a recent morning an excavator chewed away at the earth, digging a deep trench near Stover Road, west of town.
Nearby, a ribbon of black, 42-inch high-density plastic pipe waited to be buried. Once in the ground, it will carry water to thousands of acres of farmland and replace a network of open irrigation laterals and ditches that are expensive to maintain.
It's all part of an ambitious effort to be more efficient with water by the Sunnyside Valley Irrigation District, which expects to spend up to $150 million on the project.
Too often irrigation water is lost by evaporation, seepage from canals and laterals, and inefficient delivery systems.
But when finished, the district's program will save up to 60,000 acre-feet of water -- an amount almost twice the capacity of the Bumping Lake reservoir -- and return it to the Yakima River to support fish and habitat.
"When you look at the amount of money spent in the district on water conservation activities, it is a lot of money," observed district manager Jim Trull. "But it is getting real water back in the system with less environmental cost than if you are building a new reservoir."
The amount of water to be returned to the river represents more than 10 percent of what the district historically has used to irrigate lush fields of grapes, orchards and other crops stretching from Parker to Benton City.
The program got about $21.4 million in federal stimulus money this year that expedited some of the piping work.
District farmers are paying part of the cost -- about $10 per acre more in annual irrigation assessments. Most of the funding, however, is coming from the federal and state governments under a federal law that contributes money for the district to automate its canal, create small canal-side reservoirs that store water until it is needed, and to install large sections of pipe in the distribution system.
That law allows the district to keep a third of the water it saves, while two-thirds is returned to the river for instream flows.
Sunnyside agreed to the conservation program as part of the landmark Aquavella case, a decades-long court battle intended to help to settle water rights issues in the Yakima Basin.
The program illustrates part of the challenge facing irrigators, fish managers, tribal representatives, local, state and federal agencies trying to resolve basin water issues.
Providing enough water for agriculture, community growth and to restore fish will be expensive --
cost of new storage alone has been estimated at more than $2 billion.
Assuring fish passage, water conservation and a system to buy and sell water would be even more. One element alone, such as water conservation projects, won't do the trick -- but it will help.
"We obviously want to maximize conservation to the extent it makes sense from a fiscal perspective," said Dawn Wiedmeier, deputy area manager for the federal Bureau of Reclamation in Yakima. "It won't give us all the water we are short. Water conservation is a big part of it. It can't solve the problem by itself."
Environmental groups have been critical of the slow pace of work on water conservation. They argue the basin should focus on conservation before starting on the difficult task of building new storage.
The pace of conservation work has been slow -- only the Sunnyside and Benton irrigation districts have projects under way. As many as six other districts have projects in various planning stages.
Under the $37 million Benton project, plans call for water to be taken from the river at Benton City, rather than up river at Parker where that now happens. That would leave more water in the river to help fish between those two points. Plans also call for switching from laterals and canals to pipes in most of the 4,000-acre district.
Farther to the north, the Roza Irrigation District has been gradually piping laterals over the last two decades.
Roza manager Tom Monroe said the district is studying the idea of a small reservoir north of Sunnyside to hold water that's already been taken from the river until it's needed later.
Two such small reservoirs are already in place in the east end of the 72,000-acre Roza district.
Small reservoirs are a key element of the 99,000-acre Sunnyside district's plan.
Two already are in place, while a third reservoir is being built off State Route 241, north of Sunnyside.
Transferring water back and forth from the canal to the reservoir happens automatically, tied in with another element of the district's plan, automation of the main canal.
Trull said a district watermaster can monitor the canal and make changes from a laptop computer.
It's a far cry from the old days -- not that long ago -- when district ditchriders called in each morning with flow levels in district drains as an indicator of whether too little or too much water was in the canal.
What it means for the district is quicker response to changes in the canal and overall better water management.
"We can manage the daily fluctuations better. With the old system, we couldn't be very efficient because we had to carry a lot of excess water in the canal," Trull said.
* David Lester can be reached at 509-577-7674 or dlester@yakimaherald.com.