Assessing the change in the performance of a hydrological model post integrating reservoirs for Cauvery river basin, India

Abstract

All ecosystem services of river are governed by flow regime. The different components of flow regime like topography, geology, and climatic variation contribute to different ecological processes. These ecosystems provide a wide range of direct and indirect benefits to a human being. The ecosystem services such as hydropower, irrigation, drinking water supply, fisheries, breeding ground for aquatic wild life, sanctuary reserves form the lifeline of many stakeholders. All the water management decisions are based on certain hydrological informations. However, the hydrological information these decisions are based on are not precise and is a simplified version of the actual system. Anthropogenic effects of human intervention on natural flow regime significantly disturbs the natural characteristics of the hydrological flow. Hydrological alterations of river flow regime while benefitting human development in many ways have damaged the delivery of ecosystem services. Growth in human population, decline in resources, ever changing climatic conditions, led to an increase in demand of the resources.The situation is further complicated by multitude of water users and stakeholders with conflicting interests this requires the accurate assessment of the river flow regime taking into account the anthropogenic effects of human intervention in the riverine ecosystem. Reservoir construction is one of the major human intervention to the riverine ecosystem. Construction of reservoirs are usually associated with substantial impacts on river hydrology and surrounding ecosystem. As a result, dams have been constructed to meet the needs of irrigation and energy. These constructions affect the connectivity of the river and eventually changes the entire ecosystem. Topography based hydrological models simulates the response of the catchment due to the different hydrological response units(HRUs). These HRUs are natural and doesn’t take into account anthropogenic factors into account. Therefore, the present study aims to understand the effects of the integration of reservoirs into a Flex-Topo model to assess the model performance.