Estimating Evapotranspiration from Solar Radiation

An analysis of water shortages for municipal and industrial, and (project type) irrigation uses is presented. The investigation was undertaken to compile data on water shortages for these uses and to establish general practical guides for use in planning studies by governmental agencies and consulting firms. It is concluded that shortages of any magnitude should not be permitted in studies in which water is to be supplied for municipal and industrial purposes. In regard to irrigation, no firm guides and limitations based entirely on water shortages are recommended. In determining the feasibility of irrigation, economic analyses will be made, on a project by project basis, that will consider reduced crop yields due to water shortages. Desirable limits on water shortages for irrigation in planning work are considered to be as follows: Maximum average annual for 50-yr period, 3% maximum for a single year, 50% maximum for two consecutive years (total), 70% and maximum shortage years, 27%.