Theme 4-16-Hydrological modeling of a major irrigation command using MIKE SHE.

Abstract

A physically based distributed hydrological model MIKE SHE, is applied to the command of the Right Bank Main Canal (RBMC) system of Kangsabati irrigation project (a major irrigation project in West Bengal) to accurately simulate the hydrologic process. Simulation is carried out from April 1, 1997 to November 1, 1997 and the water balance of the command is computed. Depth of irrigation water applied in different canal reaches is obtained from the result of MIKE 11 hydraulic model simulation and added to rainfall to represent precipitation input in the MIKE SHE. The model is calibrated by comparing the post-monsoon observed and simulated groundwater levels at five different locations in the command. A close agreement is found between the observed and simulated groundwater levels. Saturated hydraulic conductivity (Ks) and exponent (n) of the hydraulic conductivity function are considered as calibration parameters. Variation in groundwater levels and soil moisture content in the unsaturated zone along the length of the canal is studied. Sensitivity of the calibration parameters towards simulated groundwater levels and other components of water balance are also studied. The saturated hydraulic conductivity (Ks) is found to be more sensitive than the exponent (n). The results illustrate the applicability of a comprehensive hydrological modeling system to a major irrigation command.