Lytle Water Solutions, LLC

Evaluation of the Pumpkin Creek Ground Water Allocation by the North Platte NRD

Prepared for The Central Nebraska Public Power and Irrigation District, Holdrege, Nebraska
October 2008

Introduction

The North Platte Natural Resources District (NPNRD) has been setting an annual ground water allocation of 14 inches per certified irrigated acre in the Pumpkin Creek basin since October 15, 2003. According to the NPNRD, the 14-inch ground water allocation would result in a permissible basin withdrawal of 56,092 acre-feet per year (ac-ft/yr) (NPNRD, 2004). In September 2008, the NPNRD proposed that the allocation be reduced to 12 inches.

This allocation is being set at a time when there is compelling evidence of a) significant development of wells in the Pumpkin Creek basin associated with increases in irrigated lands, b) progressive declines in discharge of Pumpkin Creek and a progressive increase in the number of "no-flow" days per year, and c) progressive reductions in surface water diversions of canals drawing water from Pumpkin Creek related to reduced availability of surface water for diversion (Drain, 2002) . These conditions prompted the Central Nebraska Public Power and Irrigation District (CNPPID) to investigate the relationship between the expansion of well use, the expansion of irrigated lands, and the reductions in surface flow of Pumpkin Creek. In particular, the investigation presented herein focuses on the appropriateness of the NPNRD's current and proposed ground water allocation in light of the known facts.

This report, prepared on behalf of CNPPID, summarizes our analysis of the ground water allocation set by NPNRD and our evaluation of whether there is a direct cause and effect relationship between the NPNRD's ground water allocation and depletions of surface water due to well pumping. We have evaluated the proposed allocation (as well as reduced allocation levels) relative to the natural recharge to the basin, surface and subsurface discharge from the basin, and the sustainability of ground water use relative to natural recharge to the basin.

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