A study on Evapotranspiration Estimation in Kashmir Valley

Abstract

The present study is aimed at the estimation of evapotranspiration with reference to Kashmir Valley, newlinewhere previously no comprehensive study on this aspect has been undertaken. This has led to the newlineframing of water-use proposals for irrigation etc. on the basis of arbitrary parameters. A more realistic newlinecrop water requirement estimation, which is mainly based on the evapotranspiration scenario of a newlineregion, can be extremely helpful in making better decisions on irrigation water use in the region. By newlinethis, the water use efficiency can be improved and the irrigation potential (Duty) of the available water newlinecan be considerably increased. newlineAs irrigation accounts for two-thirds of global freshwater withdrawals, any water-savings based on newlinethe informed decisions could significantly improve water use efficiency and, therefore, the newlinesustainability of irrigated agriculture. Reference evapotranspiration (ETO) estimation is a prerequisite newlinefor the crop water requirement determination. There is global consensus on the consistency of the newlineFAO-56 Penman Monteith (FAO-56 PM) method, and it has lately become the first choice for the newlineestimation of ETO, but despite its consistent performance, other methods continue to be popular for newlinetheir simple structure and data requirement, more so in field practice. In this study, regression models newlinewere developed for predicting monthly ETO using monthly averages of minimum temperature (Tmin), newlinerelative humidity (RH), wind speed (WS), and sunshine hours (SSH) for three different locations in newlinethe temperate Kashmir Valley. The models are based on the ETO data generated using the FAO-56 newlinePM method. For the cases of very limited data availability where the FAO-56 PM Model cannot be newlineused, the Hargreaves and Samani (HAR) equation was calibrated for each station using linear newlineregression between FAO-56 PM ETO and HAR ETO. newlineAlso, based on a previous water-balance study on Paddy in the study area, linear models for direct newlineestimation of stage-wise and growing season actual evapotranspiration were a