成都平原毗河下游生态环境需水量研究

20世纪90年代以来，河流生态环境需水成为生态水文学研究的重要内容。阐述了基于国际上新兴发展的生态水文学理论的生态环境需水量的概念和内涵。并以毗河为例，用能反映时间尺度的河流流量来表达生态环境需水量，而不是传统意义上的水量。为了与水资源配置的时间单元协调起来，对3个代表年〖WTBX〗P〖WTBZ〗=50%（1968年），〖WTBX〗P〖WTBZ〗=75%（1986年），〖WTBX〗P〖WTBZ〗=90%（1987年）分别进行生态环境需水量的计算。根据毗河的自然条件，利用Montana法计算了河道维护水生生境最小需水量和最适宜需水量；蒸发需水量由水面宽度、河道两断面间平均长度、河道蒸发深度三者确定；结合河道功能区划和水质目标，计算了污染物稀释需水量。最终确定毗河下游河道的最小生态环境需水量为20.64 m3/s，最适宜生态环境需水量为25.84 m3/s。

ECO-ENVIRONMENTAL WATER REQUIREMENTS FOR LOWER REACHES OF PIHE RIVER IN CHENGDU PLAIN

Since 1990s',research of eco-environmental water requirement for river has become an important part for eco-hydrology research.According to eco-hydrology theory,the conception of eco-environmental water requirements and the meaning were clarified.Based on the Pihe River Water Switch Project research, eco-environmental water requirements were expressed by flux which contained time information,not just water quantity.To coordinate with the water resource allocation,the article evaluated eco-environmental water requirements for three typical years,they were P=50% (1968),P=75% (1986) and P=90% (1987).Based on natural characters of Pihe River,the minimum and optimum water requirements of aquatic habitat for the river maintenance were counted by the means of Montana Theory.The Pihe River evapora- tion water requirements were counted too,which were related with the width of water surface,the length between two sections and the evaporation depth of the river.The pollutant dilute water requirements were counted on the combination of water quality goal and river function division.The minimum and optimum eco-environmental water requirements of river were ultimately ascertained as 20.64 m~3/s and 25.84 m~3/s respectively.According to the case study of Pihe River,it can be concluded that eco-environmental water requirements of river is not a numerical number,but a scope,which is practical to ensure the basic flow to downstream of water power station dam,and helpful to protect the eco-environment of the river,especially for downstream watershed.