Estimation of Potential Evapotranspiration using Empirical Models for Imphal
Nganthoi Naorem1, Th. Kiranbala Devi2

1Nganthoi Naorem, Department of Civil Engineering, Manipur Institute of Technology, Takyelpat Imphal.
2Dr. Th. Kiranbala Devi, Manipur Institute of Technology, Takyelpat Imphal.
Manuscript received on 10 December 2014 | Revised Manuscript received on 20 December 2014 | Manuscript Published on 30 December 2014 | PP: 119-123 | Volume-4 Issue-7, December 2014 | Retrieval Number: G1941124714/14©BEIESP
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Abstract: Estimation of evapotranspiration of an area is highly essential for irrigation scheduling and design of irrigation project. It is the basic parameter for estimating the crop water requirements. In this study, Potential evapotranspiration (PET) were computed using 10 empirical models viz. Blaney-Criddle, Thornthwaite, Hargreaves, Penman, Penman-Monteith, JensenHaise, Turc, Priestley-Taylor, Makkink and Open pan method with the help of climatological data for the year 2012 for Imphal, Manipur. The missing climatic data to be used in the empirical models are computed according to the guidelines given in FAO Irrigation and Drainage paper, 56.FAO Rome, Italy. The empirically estimated PET from all these models were validated with the actual measured mesh covered pan evaporation value using calibration co-efficients. From the study, Hargreaves method was found to be the most suitable method for the region with least biasness and minimum error. The calibration coefficients developed in this study can be used for reducing the error of estimating evapotranspiration by these empirical models for the area under study.
Keywords: Calibration Co-efficients, Error Analysis, Missing Climatic Data, Pan Evaporation, Potential Evapotranspiration.

Scope of the Article: Structural Reliability Analysis