Updating Utah's Crop Water Use Estimates

Hill, R. W.; Austin, L.; Olds, J.; Stauffer, N.; ,

Updating Utah's Crop Water Use Estimates

by R. W. Hill, Utah State Univ, Logan, United States,
L. Austin, Utah State Univ, Logan, United States,
J. Olds, Utah State Univ, Logan, United States,
N. Stauffer, Utah State Univ, Logan, United States,

Document Type: Proceeding Paper

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

Abstract:

Crop water use was estimated at National Weather Service stations throughout Utah for the 1961-1990 normal period. Daily weather data (air temperature, solar radiation, humidity, wind and precipitation) were available at Utah Climate Center electronic weather stations. Sufficient data from these stations for using Penman equation were available only for the 1982-1991 period. Monthly temperature and precipitation data at the NWS weather stations were used for the normal period 1961-1990. Thus, to complete the historical consumptive use calculations, equations based only on air temperature data could be considered. The modified Penman equation (Kimberly, Idaho, calibration) was used to determine daily and monthly total crop E_t. This was then used to calibrate crop coefficients for the Blaney-Criddle method to estimate historical monthly E_t. Net irrigation requirement was calculated as growing season E_t less the effective summer precipitation (approximately 80% of total rainfall). The results are presented by months for selected crops at each NWS station. A modification of the Penman equation based on the Kohler, Nordensen and Fox method was used to estimate open water surface evaporation.

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