The physically based distributed modelling system, MIKE SHE, is used to simulate the hydrological water balance of a small watershed with the objective of developing the irrigation plan. Simulation is first conducted over 109 days, concentrating the attention on the main cropping season, i.e., kharif (Jul-Oct), and the average water balance is calculated. It is observed that in spite of the frequent rainfall in the season, there are phases when the water content in the root zone goes below the allowable deficit. In case irrigation is not supplied during these periods, the yield of the paddy will only be about 70% of the potential yield. To attain the potential yield, the irrigation requirement is calculated as 490 and 340 mm for the upstream and downstream ends of the watershed respectively. Irrigation schedule for the purpose is suggested. Hydrological water balance simulation is further extended to the second cropping season, i.e., rabi (Nov-Feb), over 100-day period. Here, the water stored in the existing tank at the outlet is used for the supplemental irrigation in the season. It is seen that the actual yields obtained are very close to the potential yields of the selected crops. The results overall illustrate the applicability of a comprehensive hydrological modelling system for the management of water resources for agricultural purposes in a watershed.
- Programområde 2: Vandressourcer