Calibration and validation of the canal simulation model: A case study on Nawagarh Distributary of Janjgir Branch Canal, District- Janjgir-Champa (Chhattisgarh, India)

Abstract

Optimal irrigation scheduling and crop planning are the essential tasks for obtaining the maximum benefit from an irrigated command with the available water resources. This task can be achieved by assessing the irrigation system performance under existing scenarios. Keeping this in view, the present study was carried out to assess existing water supply-demand gap of the Nawagarh Distributary (Block-Nawagarh, District- Janjgir-Champa) of Hasdeo Bango Major Irrigation Project (District- Janjgir-Champa), Chhattisgarh, India. The required data on crop, weather; soil and canal flow pertaining to the study area were collected during the years 2012 and 2013 from various government departments, organizations and personal contact with the farmers of the command. To assess the existing supply-demand scenario of Nawagarh Distributary, CROPWAT 8.0 model was used. CROPWAT is a decision support system developed by the Land and Water Development Division of FAO in 1990 for planning and management of irrigation. CROPWAT is meant as a practical tool to carry out standard calculations for reference evapotranspiration, crop water requirements and crop irrigation requirements, and more specifically the design and management of irrigation schemes. The selected model uses the FAO (1992) Penman-Montieth method for calculating the reference crop evapotranspiration. The model calibration was performed for the year 2012. The Root Mean Square Error (RMSE), Nash-Sutcliffe Coefficient (Ce), Correlation Coefficient (r2), and Coefficient of Determination (R2) were used as performance measures for calibration and validation. The model validation was carried out for the year 2013. The selected model was calibrated against the estimated (called as observed value) daily ETo and decade ETc. The model simulated daily ETo and decade ETc matched well with the estimated daily ETo and decade ETc for the study period considering served area and potential area.