Assessment of the degree of hydrological indicators alteration under climate change

摘要

The native biodiversity and integrity of riverine ecosystems are dependent on the natural flow regime. Maintaining the natural variability of flow in regulated river is the most important principle for the operation and management of environmental flow (e-flow). However, climate change has altered the natural flow regime of rivers. Flow regime alteration is regarded as one major cause leading to the degradation of riverine ecosystems. It is necessary to incorporate the impacts of climate changes into e-flow management. To provide scientific target for e-flow management, the assessment method for flow regime alteration is developed. We analyze the alteration of hydrological indicator under climate change. This study has selected the commonly used Indicators of Hydrologic Alteration (IHAs) to describe the various aspects of flow regimes. To assess the alteration degree of each IHA in regulated river under climate change, GCM is used to generate feasible future climate conditions and hydrological model is used generate flow of river from those future weather conditions. Then the values of IHAs are derived from historical and simulated flow data. The relationship between IHA and climate variable is analyzed based on analysis method. The IHA, which is more influenced by the climate variables, can be selected for the preparation of reservoir operation.