Water Transfer: Applicants and Objectors Analyses

Walter, Ivan A.; Altenhofen, Jon; ,

Water Transfer: Applicants and Objectors Analyses

by Ivan A. Walter, W. W. Wheeler and Associates, Inc, Englewood, United States,
Jon Altenhofen, W. W. Wheeler and Associates, Inc, Englewood, United States,

Document Type: Proceeding Paper

Part of: Management of Irrigation and Drainage Systems: Integrated Perspectives

Abstract:

Two different analyses of the historical on-farm consumptive use and return flows of agricultural water rights in Northern Colorado are discussed. The City of Thornton plans the transfer of the water rights from agricultural to municipal use. Thornton's engineering of the historical on-farm use of the water rights was analyzed by the Northern Colorado Water Conservancy District (NC) and W. W. Wheeler & Associates, Inc. (WWW) and found to be not representative. This paper discusses the different procedures used to quantify crop potential evapotranspiration (Etp), irrigation water requirement (IWR) and irrigation application efficiencies. The average annual IWR was estimated by Thornton using SCS-BC and TR21 to be 450 mm. NC&WWW utilized reference crop Etp in a daily soil moisture budget and estimated the IWR to range from 345 to 380 mm. Thornton's irrigation application efficiencies and percent lost to deep percolation and runoff were based on SCS design handbook with non-site specific data assumed for values in the design equations and tables. NC&WWW measured field efficiencies and irrigation parameters and found that actual efficiencies were much lower than Thornton's estimated values and that several of Thornton's assumptions were not valid. The results of the two different analyses were that Thornton estimated historical consumptive use to be 14,880 acre feet; NC&WWW estimated it to be 10,032 acre feet.

Return to search