Development of a System Dynamics based Irrigation Demand Model

Water resources globally are under severe threat due to population growth, intensive socio-economic development, change in climatic condition and increasing level of conflict among multiple water users. Under this context, an accurate and efficient supply-demand management of this critical resource is highly essential to ensure the water security of a region. Agriculture being the major water user, needs to be given primary importance. However, in canal command areas, there is an inefficient management of irrigation system without considering the real-time irrigation demand while supplying the irrigation water from the reservoir. This leads to either surplus or deficit irrigation supply throughout the year affecting both the water sector and the crop yield of the command. The real-time irrigation demand of a command depends upon the type of crops grown, antecedent soil moisture content and meteorological variables along with the social attributes of the stakeholders. Hence, this current study tries to develop a dynamic irrigation demand model comprising of all the afore-mentioned variables under system thinking approach. The causal feedback among the system elements were developed initially through causal loop diagram and the model variables were subsequently transformed into stocks and flows, representing the dynamic state of the system in order to develop the conceptual model. The developed model was tested in the Hirakud canal command located in the eastern part of India simulating the real system effectively. This developed model can be used by the water managers for efficient irrigation planning in a canal command ensuring overall water and food security of the region.