The drastic decline in groundwater table and many other detrimental effects in meeting irrigation demand, and the projected population growth have force to evaluate consumptive use or evapo-transpiration (ET), the rate of liquid water transformation to vapor from open water, bare soil, and vegetation, which determines the irrigation demand. As underscored in the literature, Pen-man-Monteith method which is based on aerodynamic and energy balance method is widely used and accepted as the method of estimation of ET. However, the estimation of ET is oftentimes carried out using meteorological data from climate stations. Therefore, such estimation of ET may vary spatially and thus there exists a need to estimate ET spatially at different spatial or grid scales/resolutions. Thus, in this paper, a spatial tool that can geographically encompass all the best available climate datasets to produce ET at different spatial scales is developed. The spatial tool is developed as a Python toolbox in ArcGIS using Python, an open source programming language, and the ArcPy site-package of ArcGIS. The developed spatial tool is demonstrated using the meteorological data from Automated Weather Data Network in Nebraska in 2010.
References
[1]
WWAP (World Water Assessment Programme) (2015) United Nations World Water Development Report 2015: Water for a Sustainable World. United Nations Educational, Scientific and Cultural Organization, Paris.
[2]
WWAP (World Water Assessment Programme) (2012) United Nations World Water Development Report 4: Managing Water under Uncertainty and Risk. United Nations Educational, Scientific and Cultural Organization, Paris.
[3]
Postel, S.L., Daily, G.C. and Ehrlich, P.R. (1996) Human Appropriation of Renewable Fresh Water. Science, 271, 785- 788. http://dx.doi.org/10.1126/science.271.5250.785
[4]
Jensen, M.E., Burman, R.D. and Allen, R.G. (1990) Evapotranspiration and Irrigation Water Requirements, Manuals and Reports on Engineering Practice. ASCE No. 70, New York.
[5]
Richard, G.A. and William, O.P. (1986) Rational Use of the FAO Blaney-Criddle Formula. Journal of Irrigation and Drainage Engineering, 112, 139-155. http://dx.doi.org/10.1061/(ASCE)0733-9437(1986)112:2(139)
[6]
Allen, R.G., Pereira, L.S., Raes, D. and Smith, M. (1998) Crop Evapotranspiration-Guidelines for Computing Crop Water Requirements. FAO Irrigation and Drainage Paper 56, United Nations Food and Agriculture Organization, Rome.
[7]
Gong, L.B., Xu, C.Y., Chen, D.L., Halldin, S. and Chen, Y.Q.D. (2006) Sensitivity of the Penman-Monteith Reference Evapotranspiration to Key Climatic Variables in the Changjiang (Yangtze River) Basin. Journal of Hydrology, 329, 620-629. http://dx.doi.org/10.1016/j.jhydrol.2006.03.027
[8]
Bakhtiari, B. and Liaghat, A.M. (2011) Seasonal Sensitivity Analysis for Climatic Variables of ASCE Penman-Monteith Model in a Semi-Arid Climate. Journal of Agricultural Science and Technology, 13, 1135-1145.
[9]
Kevin, F.D., Thomas, E.R. and William, L.C. (2015) Groundwater Availability in the United States: The Value of Quantitative Regional Assessments. Hydrogeology Journal, 23, 1629-1632.
http://dx.doi.org/10.1007/s10040-015-1307-5
[10]
U.S. Census Bureau (2015) Annual Estimates of the Resident Population for the United States, Regions, States, and Puerto Rico: April 1, 2010 to July 1, 2014. U.S. Census Bureau, Suitland, Maryland.
[11]
Nebraska Surface Water and Groundwater Use—2005. Nebraska Department of Natural Resources.
http://www.dnr.ne.gov/nebraska-surface-water-and-groundwater-use-2005
