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This agreement is made and entered into by and between the Department of Ecology, and Washington State University for the Evapotranspiration and Consumptive Irrigation Requirements for Washington and for updating of the Washington Irrigation Guide (WIG).
It is the purpose of this agreement to provide funding to the recipient and to update existing crop water use tables by employing recent weather data, and more current and accurate methods, equations and parameters.
Ecology, WSU and NRCS have developed a Scope of Work to update the Washington Irrigation Guide. However, because of the widespread use of this document by Washington State stakeholders, Ecology asked for comments on the proposed scope before funding the work. Ecology received comments from the public on the scope of work between January 22 to February 22, 2008. Those comments may be incorporated into the scope of work.
Over the last 40 years, Ecology has collaborated with Washington State University and various state and federal agricultural agencies to produce guidance documents that estimate crop irrigation requirements. This information was used for many different purposes, including:
The first such document, published in 1969, was called “Circular 512” and provided crop irrigation requirements for 38 locations throughout Washington for 18 different crops. These data were compiled using the modified Blaney-Criddle procedure from 30 years of weather records.
The second guidance document, Irrigation Requirements for Washington—Estimates and Methodology, was published in 1982 and is still in print today. This guidance document estimates crop irrigation requirements for 40 locations throughout Washington for 39 different crops. These data were compiled using the Doorenbos and Pruitt Blaney-Criddle method based on 26 years of NOAA weather data.
The most recent guidance document, the State of Washington Irrigation Guide (WIG), was published in 1985 and supplemented in 1992. It remains the definitive irrigation guidance document in use today. This guidance document estimates crop irrigation requirements for 90 locations throughout Washington for 60 different crops. These data were compiled using the Doorenbos and Pruitt Blaney-Criddle and SCS Blaney-Criddle Modified methods based on up to 29 years of NOAA weather data.
Good data is required to manage Washington’s water resources. Updating the WIG is important because:
| Daniel R. Haller, P.E. Columbia River Program Department of Ecology, Central Region Office Phone: (509) 454-4255 E-mail: wig@ecy.wa.gov |
Troy Peters, P.E. Irrigation Engineer, Extension Specialist WSU Prosser Phone: (509) 786-9247 E-mail: troy_peters@wsu.edu |
Copyright © Washington State Department of Ecology. See http://www.ecy.wa.gov/copyright.html.
