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Snake River Delivery Calls
Client: City of Pocatello, Idaho
Water Resources Engineering - Water Rights Protection, Injury Analysis

The City of Pocatello is located in southeastern Idaho and supplies water to approximately 50,000 residents.  The primary source of water for the City is ground water pumped from municipal wells constructed in the Lower Portneuf River Valley Aquifer.  The City also pumps ground water from the Eastern Snake Plain Aquifer, which is a very large, prolific, basalt aquifer that covers approximately 10,800 square miles in southeastern Idaho. SWE has provided on-going consulting services for the City of Pocatello since 1993 on a wide variety of water resource related issues, such as representing the City's interests on the Eastern Snake Hydrologic Modeling Committee, providing expert testimony and litigation support for legal proceedings regarding surface water and ground water rights on the Eastern Snake Plain, assisting the City in adjudicating its' water rights, and evaluating water supply alternatives.

SWE served as Pocatello's technical representative regarding the development of the Conjunctive Management Rules adopted by the Idaho Legislature in 1994.  In 2005, a Delivery Call was placed by the Surface Water Coalition ("SWC"), a consortium of seven lower Snake River Valley ditches, requesting priority administration of Eastern Snake Plain Aquifer ground water rights, according to the Conjunctive Management Rules.  SWE evaluated the injury claims made by the SWC, and IDWR's Orders responding to the Delivery Call, which required mitigation water to be provided to the SWC.  SWE performed an analysis of the potential injury to the SWC based on applicable legal principals and the Conjunctive Management Rules.  The injury analysis used a water budget approach to compute the consumptive irrigation demands of crops irrigated by the SWC and estimated actual water shortages in meeting crop demands. 
A separate historical consumptive use analysis was performed for each of the seven ditches involved in the Delivery Call.  The combined number of irrigated acres involved in the historical consumptive use analysis was 563,000 acres.  The average annual diversions for the seven ditches totaled 3,232,000 acre-feet.
SWE prepared an expert report and rebuttal reports, assisted with discovery and depositions, and provided expert testimony at a fourteen day hearing conducted in 2008 involving the SWC, the Idaho Department of Water Resources, the United States Bureau of Reclamation, Idaho Ground Water Association, and the City of Pocatello.

In 2007, the A&B Irrigation District, an irrigation district that owns senior ground water rights within the Eastern Snake Plain Aquifer, renewed a Delivery Call initiated in 1994 whereby the District was seeking curtailment of junior ground water users.  SWE evaluated the injury claims made by the A&B Irrigation District and the IDWR Order responding to the Delivery Call. A&B Irrigation District alleged, among other things, that the reduction in A&B's well diversions were the result of declining water levels caused by junior well pumping.  SWE's evaluation of the claims involved an analysis of A&B's water rights and well delivery criteria, determination of actual irrigation water requirements, and analysis of A&B's claim for damages.  SWE prepared an expert report, rebuttal report and provided expert testimony at a ten day hearing in 2008.  

Spronk Water Engineers, Inc.
1000 N Logan Street
Denver, Colorado, 80203-3011
Phone: (303) 861-9700  |  Fax: (303) 861-9799