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Idaho Water Success Story: A&B Irrigation District, Pumping Plant #2 and Pipe

This map shows the location and extent of the A & B Irrigation District project.The A&B Irrigation District, Pumping Plant #2 and Pipeline Project (Groundwater to Surface Water Conversion) is located in Southern Idaho. Found in Minidoka County near Rupert and Burley, the project is intersected by Interstate 84. “A&B,” as it is called, now serves nearly 6,500 acres utilizing almost 19 miles of pipe and 3500 horsepower.  

A&B was conceived to achieve three goals:

1. Address declining aquifer levels by decreasing groundwater withdrawals through new infrastructure (pumping plant and a closed pipeline system) that delivers surface water from the Snake River to acres previously irrigated with groundwater;

2. Improve delivery efficiencies within the service area through the conversion of open canals & ditches to an enclosed pipeline system – this reduces both aquifer draft (groundwater) and surface water removed from the Snake River; and

3. Energy savings from reduced “lift,” reduced volume of water pumped, and state-of-the-art pump and motor efficiencies at the new pumping plant.

In addition to the A&B Irrigation District and NRCS, the Idaho Water Resource Board, Idaho Department of Water Resources, Bureau of Reclamation, Bonneville Power Administration, local Conservation District, Idaho Power, Diamond Plastics, CH2MHill Engineering and Knife River Corporation all played important roles in the project.

Workers on the A & B Irrigation District project position a reducer to join 54-inch and 48-inch PVC pipe together.Early planning for A&B took place in 2011/2012. NRCS funds were obligated in 2013 and NRCS did the design in-house for everything except the electrical side, which was done by CH2MHill. The design underwent independent review by NRCS-Ft. Worth and the Bureau of Reclamation-Denver.

Environmental Compliance was an important part of the process and the project underwent the full NEPA review with the Bureau of Reclamation as the lead agency. The Environmental Assessment returned with a Finding of No Significant Impact. Coordination with the Bureau of Reclamation included engineering design and construction as well as environmental compliance.

Construction took place during the winter that bridged 2015 and 2016. This was necessary as on a project this size, work has to be done outside of the summer irrigation season.

Winter conditions presented predictable problems, such as snow and other inclement weather, but the build itself had some particular challenges. There was lots of “big pipe” to be moved and installed.  More than 15,000 feet of 48” and 54” PVC pipe were laid during the project and the challenge inherent with pipe of that scale led to the development of the pipe groove tool for the granular embedment. And then there was making sure that 19-plus miles of pipe was properly received, staged, laid and aligned. At the pumping plant site, there were dewatering issues as a result of its location next to the Snake River and the A&B Irrigation District had to have the water level lowered to make for a sediment-free breach to the inlet bay the pumps draw from.Regional Conservationist Astor Boozer (left) and NRCS State Irrigation Engineer Dan Murdock (right) and  check out the screens that are part of the pumping station for the A & B Irrigation District project.

The system became fully operational in the summer of 2016. The total project cost was $12Million and funding came through the NRCS Agricultural Water Enhancement Program (AWEP) along with financing from Idaho Water Resource Board.

A&B, now draws between 5,000 and 6,000 acre-feet per year from surface water rather than the aquifer. In addition, the pumping station’s technology only moves the amount of water that is actually needed – no spills, with less noise thanks to its low-speed pumps and at a savings of 1,100HP to the grid.

This is one of more than 10 similar-scale projects that NRCS-Idaho has executed over the last dozen+ years. For example, EQIP WaterSMART-Initiative funds are currently obligated to the last phase of Marysville as well as to King Hill Irrigation District which has a project very similar to A&B. The primary difference is that the King Hill project is not a “soft conversion”, but rather a new pumping plant at a location with lower lift and higher efficiencies. There will be notable water quantity savings from significant increases in delivery efficiency and reduced volume of water pumped that result from the conversion of open canals/ditches to a closed pipeline system.