Introduction A method for estimating monthly irrigation requirements was needed for the Upper Green River Basin of Wyoming to properly size proposed reservoirs. Monthly irrigation requirements are equal to monthly crop evapotranspiration, less monthly precipitation. The simplest and most commonly used method in the western United States to estimate monthly evapotranspiration is the Soil Conservation Service version of the Blaney-Criddle method (SCS, 1967). This method requires only mean monthly temperature to estimate monthly evapotranspiration. Thus, mean monthly precipitation and temperature for the growing season are the minimum climatic measurements necessary to determine evapotranspiration rates and subsequent irrigation requirements.
Historic measurements of temperature and precipitation were limited in the Upper Green River Basin which comprises some 38,800 square km. Long-term data were available from twelve National Heather Service stations. Therefore, a practical, theoretically correct method was needed to estimate monthly temperature and precipitation, respectively, at ungaged sites in the Basin.
Water Resources Publications List Water Resources Data System Library | Water Resources Data System Homepage