Mathematical Modeling in Irrigation and Flood Management

The economy of Bangladesh predominantly depends upon agriculture. About 70 % of the population is dependent on agriculture. In the next 25 years, the population of the country is expected to increase by 40 %. This increase of population will increase the food demand of about 29 %. The changes in the agricultural area have important implications for food production as the reduced area implies an increase in cropping intensity on the remaining land. Planned utilization and efficient management of water resources for irrigation is one of the most crucial elements for achieving desired changes in agricultural production which calls for application of an integrated hydrological modeling tool. Most of the irrigation projects in Bangladesh are implemented 30–40 years ago. Nowadays, lots of infrastructural changes have been occurred. The irrigation canal command area conceived earlier has been changed, and many drainage routes have been blocked. As the hydraulic events are dynamic and changes occur every year, it is very difficult to provide solution of these complex situations for the normal prevailing method without modeling technique. Modeling technique can provide sustainable solution considering impacts of different scenarios for irrigation, flood, and drainage improvements. This paper highlights the case study of Teesta Barrage Project (TBP) Phase-I. This case study shows how the state-of-the-art technologies could be used for irrigation and flood management in irrigation project. The application of modeling tool in TBP phase-I opens up a new dimension of models as a very useful tool in Command Area Development Project. After the completion of TBP Phase-I, the project experienced water-logging problems at several locations coupled with the fact that the potential irrigable areas did not get irrigation. Under CAD project of TBP phase-I, IWM carried out detailed hydraulic model study for the irrigation and drainage systems in an integrated way to find remedial measures. A comprehensive data collection program including topographic survey has been carried out in connection with this study. Updated topographic map has been developed, and command area has been redelineated based on this map. A number of problems were identified, and corresponding solutions have been established based on the study. Most of the suggestions related to irrigation and drainage have already been implemented, and the results are found very much satisfactory. These are definitely positive indications of the successful utilization of modeling tool for better management of water resources projects. Computer-based interactive information system (IIS) for the whole project area and decision support system (DSS) for a pilot area have been developed for better management of the project.