The Central Nebraska Public Power and Irrigation District’s board of directors agreed Monday to enter an agreement with an engineering firm to conduct the second phase of a study of a “mound” of underground water in south central Nebraska.
The mound is actually a rising level of underground water in the aquifer, primarily beneath Gosper, Phelps and Kearney counties, as well as a relatively small area of adjacent counties, Central spokesman Jeff Buettner said Monday.
The “mound” is the result of seepage from the floors of canals and reservoirs, as well as saturation from farm irrigation over the years, Buettner said.
The topic was an action item at a meeting of Central's board of directors. The study will be conducted by EA Engineering, Science and Technology, Inc. of Lincoln.
It is intended to produce a better and broader understanding of the groundwater supply in the area that has developed because of Central’s hydro-irrigation project; and provide an understanding of the temporal and spatial changes in the mound; and identify factors affecting the mound.
“We have good data to feed into the study,” said Natural Resources Manager Mike Drain. “We have been monitoring various aspects of the mound for many years, including surface water deliveries, groundwater levels, drainage ditches, tile drains, groundwater change maps produced by other entities and more.”
“We have long adhered to the saying, ‘If you can’t measure it, you can’t manage it,’ in regard to water supplies,” Drain said.
The study will provide greater focus on recent and ongoing changes that affect the mound, Drain said.
Over the years, he said, on-farm conservation and improvements in irrigation efficiency have resulted in a lower demand for water diversions into the area. In addition, drought cycles and increased pumping are factors that also influence the amount of available water underground.
The study will also produce more detailed and focused data on the mound than what is currently available, particularly how the mound has reacted to various factors since 2000.
The study’s scope will include compilation of existing data; an estimate of the volume of water in the mound; an evaluation of the shape and movement of the mound; a determination of sub-areas within the mound; and development of an annual water balance.
“We have spent a lot of money over the years to improve the district’s facilities and operations,” said Central Director Robert Garrett of Minden. “We need to protect the economy of this area and the viability of our irrigators’ water supply and I think that conducting this study is an important part of that effort.”
Also at Monday’s board of directors meeting, the board:
• Passed a budget amendment for an additional $106,400 to cover costs of repairing the bypass valve at Kingsley Hydroplant in the dam at Lake McConaughy.
Engineering Services Manager Eric Hixson reported that the additional expense was necessary because there was more wear and tear on the valve than originally expected. The bypass valve was originally designed to allow releases through the hydroplant when the plant was not generating power, but has been used for many years to add oxygen to the water in Lake Ogallala to meet water quality standards and benefit the trout fishery.
• Authorized $200,000 to replace two 115-kV breakers for switchyards at supply canal hydroplants. The board also approved the purchase of remote station radios at a cost of $64,800 in conjunction with the Supervisory Control and Data Acquisition system upgrade.
• Approved one-year irrigation water service transfers for 24,696 acres, part of Central’s efforts to conserve water supplies in Lake McConaughy by allocating irrigation deliveries in 2013.
• Approved, subject to legal review, a proposal to offer water conserved as a result of a 1992 agreement with the Nebraska and National Wildlife Federations to the Platte River Recovery Implementation Program.
The offer satisfies an article in Central’s Federal Energy Regulatory Commission license that requires Central to offer to the program a volume of water identified as “net controllable conserved water” that was achieved through efforts to reduce irrigation diversions into Central’s system, Buettner said.