Simulation of chain of tanks to augment water supply: a case study from Tamil Nadu

The application of system dynamics techniques is gaining significance and is much needed for an effective management of the depleting water resources in a dynamically complex region and considers it as the feedback from the system. The present study deals with the application of a system dynamic approach to simulate a chain of four tanks in the Guduvanchery watershed, Tamil Nadu, India. Standard data-driven models cannot be effectively used due to a lack of quality data for ungauged basins. VENSIM was used for the system dynamic simulation to assess water availability for the sustainable management of water resources. Inflow into the four tanks, net losses in each tank, and crop water requirement were given as inputs into VENSIM. Along with different models, an extensive field survey was carried out to quantify each input component. Based on system dynamics simulation, only 28% of the total available water is used for irrigation and the rest is wasted due to evaporation, transition loss, and spill from the tanks. It was found that there was approximately 5.46 MCM of surface water available in the watershed, and it will be able to supply the domestic demand of the watershed of 0.672 MCM in addition to the irrigation requirement.