The Central Nebraska Public Power and Irrigation District is in the process of partially filling Elwood Reservoir in preparation for the 2015 irrigation season.
With irrigation customers limited to 12 inches/acre over the coming irrigation season, a completely full Elwood Reservoir will not be necessary. Instead, Central will divert 15,000 acre-feet of water into Elwood, raising the reservoir’s elevation to about 2,602 feet by the end of May. The normal maximum elevation is 2,607 feet.
By limiting the amount of water pumped into the reservoir, Central will be able to conserve thousands of acre-feet in Lake McConaughy. Central’s storage rights require that water pumped into Elwood Reservoir for irrigation purposes must be a transfer of storage water from Lake McConaughy.
To accomplish the fill schedule, Central plans to operate two of the three pumps at the Carl T. Curtis Pump Station in April, and then use one pump during May to reach the intended level. The pumping process will raise the reservoir’s elevation by 14 feet between April 1 and the end of May.
In addition to providing water for irrigation customers, inflows into the reservoir will benefit the fishery at the lake, as well as providing some incidental groundwater recharge benefits. Central, in cooperation with Tri-Basin NRD and the Nebraska Department of Natural Resources, had diverted 15,000 acre-feet into the reservoir for groundwater recharge last year – water that was in excess of target flows and other uses in the Platte River – and then added another 15,000 acre-feet for recharge purposes in December and January. Water that is pumped into the reservoir is allowed to seep into the ground, thereby helping the area’s groundwater level, as well as augmenting base flows in the Platte River as the water eventually moves underground back to the river.