NAMPA, Idaho — Farmers who get their water from the largest irrigation district in Idaho’s Treasure Valley will end the season with an abundant supply of carryover water for the 2018 growing season.
Near-record snowpack in the Boise River basin provided an abundant supply of water this year to irrigators who depend on the Nampa & Meridian Irrigation District, which supplies water to 69,000 acres of irrigated land in southwestern Idaho.
“In my lifetime, it was the No. 1 water year,” said Clinton Pline, a farmer and member of NMID’s board of directors.
The snowpack provided the second-highest amount of runoff in the basin on record, according to U.S. Bureau of Reclamation data.
Total runoff was 3.145 million acre-feet this year, second only to 3.195 million acre-feet in 1943.
Because Boise River flows remained high all season, that allowed NMID to get the majority of its water from natural flows in the river and the district had to use very little of the water it has stored in the Boise River system’s three major reservoirs.
“The (flow) of the river right now is still up quite a bit from what it normally is this time of year,” said NMID Water Superintendent Greg Curtis.
NMID, as well as other irrigation districts that get their water from the Boise River system, will have a large supply of carryover water stored in the reservoirs that they can use in 2018.
On Sept. 1, the reservoirs had a combined total of 663,000 acre-feet of storage water, according to the Bureau. That’s well above the 30-year average of 473,000 acre-feet on that date for the reservoir system, which has a total capacity of just under 1 million acre-feet.
The exact amount of carryover water NMID will have hasn’t been determined but “it’s substantial,” Curtis said. “We should have very good carryover going into next year.”
Water was released from the reservoirs at a record rate this spring and summer to prevent major flooding in the valley and the Bureau and Army Corps of Engineers did a great job of balancing the need to release large amounts of water while ensuring the reservoirs still filled to capacity, said Will Patterson, chairman of the NMID board of directors.
“There are always a lot of folks that want to second-guess them but they did a nice job and they need to be commended,” he said.
NMID will stop flows to its 500 miles of canals on Oct. 11.
After the canal system has dried, the district will launch several large construction projects, including the lining of some canals with concrete.
Lining of the canals has picked up steam in recent years as large new developments have supplied the concrete for the projects, while NMID employees provide the labor, Curtis said.
That is allowing the system to become more efficient, he said.
“It’s helping us keep some more water in storage because we’re not losing it through the canals,” Curtis said.