Development and testing of a GIS integrated irrigation scheduling model

A user-friendly window based irrigation scheduling model (ISM) developed by George et al. [Agric. Water Manage. 46 (2) (2000) 121] was modified by incorporating a rice irrigation scheduling model and integrated with Geographic Information System (GIS) software. The developed rice irrigation scheduling model is based on a daily water balance approach. The model was tested by comparing daily simulated and measured water depths for kharif (monsoon) 1999 and rabi (dry) 2000 seasons for outlet 5 l (12.2 ha) of the Tarafeni South Main Canal (North) in the Kangsabati irrigation project, West Bengal, India. The model testing criteria consisted of graphical comparison between simulated and measured water depths; deviation of water depth, Dd (%); Nash–Sutcliff coefficient, R2; and z-test. The model predicted daily water depth reasonably well for both single and multiple field cases and performed better during rabi than kharif season. The model application to the service area (command) of lateral (distributary) 2 l (910.4 ha) revealed that the supply was sufficient to meet about 60 and 23% of the demand, respectively for kharif 1999 and rabi 2000 seasons. Therefore, simulations were done to estimate irrigation demand for an alternative rabi crop (wheat). The comparison between supply and demand revealed that the supply was adequate to meet the irrigation demand of the distributary, and, thus wheat can be taken as an alternate crop during rabi season. Based on the results, it can be said that the ISM is a user-friendly model and can be used for irrigation management at different spatial scales.