基于流量恢复法的黄河下游鱼类生态需水研究

运用流量恢复(the flow restoration methodology)方法研究黄河下游鱼类生态需水,其基本思路是:首先获得所保护鱼类生态习性相关的流量信息,包括水深、流速、水量等.然后建立概念性模型,确定鱼类和特定流量组分之间的联系.在此基础上,确定流量目标,每一个流量目标被赋予一些水力指标,作为获得满足这个目标的环境流量计算的依据.运用水文学、水力学模型确定满足这些流量目标需要的水流条件,包括数量、持续时间、频率和发生时间,给出满足鱼类生长需要的生态流量.最后给出不同水资源管理情景下可接受的鱼类生态需水.

ENVIRONMENTAL FLOW REQUIREMENTS BY MAJOR FISHES IN THE LOWER REACH OF THE YELLOW RIVER DETERMINED BY FLOW RESTORATION

The Yellow River in China is environmentally degraded severely as a result of anthropogenic changes, most notably the regulation and extraction of surface water resources for irrigated agriculture. Environmental problems include decline of native fish, reduction in total area of riverine wetlands, water quality degradation. There is a growing awareness and understanding for the need to allocate water along a river to maintain ecological processes that provide goods and services. The government is committed to improving the environment on the Yellow River, and to ensure river health. In this paper, flow restoration method was used to calculate environmental flow for fish in the lower Yellow River. Firstly, flow-related information on selected fish in the lower Yellow River was obtained, including fish species composition, abundance and habitat use in relation to flow conditions. Then a model linking selected fish to key aspects of the flow regime was developed. This model provides a means for communicating important linkages between fish and specific flow related processes that must be maintained in order to protect those fish. Thirdly, the environmental flow objectives were identified. Fourthly, hydraulic and hydrologic models were used to determine the magnitude, duration, frequency and timing of flows required to meet these objectives. Finally, ecological consequences of several scenarios of flow management were described, to indicate the risk of ecological harm to fishes for each scenario.