Dynamic Simulation of Ecological Flow Based on the Variable Interval Analysis Method

Abstract

Ecological flow is an important basis for maintaining the structure and function of river ecosystems, and ensuring the sustainable development of economies and societies in river basins. In order to solve the problems of unclear concepts of ecological flow, difficulty in adapting to dynamic changes in demands, and the hydrological conditions and poor operability of calculated results of a practical application, a variable interval analysis method (VIAM) was proposed to calculate the ecological flow. The method comprehensively considered a variety of variable factors, such as spatial–temporal scale changes, hydrological condition changes, ecological service object changes, and calculation method changes. On the basis of a relatively fixed ecological base flow, a variable lifting amount was added to determine the ecological flow, and the ecological flow was a variable interval. Taking the Wei River as an example, the VIAM was validated and applied. With the support of a knowledge visualization integrated platform, the ecological flow simulation system of the Wei River was constructed. The results show that: (1) the VIAM makes the ecological flow calculation more scientific and reasonable, and the ecological flow of the Wei River from the upper reaches to the lower reaches increases gradually under the influence of water inflow, sewage discharge, and erosion and deposition of sediment, and the annual total water demand of the upper limit of ecological flow in a dry year is 1.04 billion m3, 1.63 billion m3, 2.29 billion m3, 4.09 billion m3, and 4.66 billion m3; (2) the variable interval is used to describe the ecological flow, which has strong applicability and operability; (3) the simulation system can quickly adapt to the demand changes in practical application, and provide visual decision support for managers. The VIAM provides new ideas and references for comprehensively promoting the control of the ecological flow.