桂林市桃花江流域生态环境需水量分析

Analysis on Eco-environmental Water Demand in Taohuajiang Basin of Guilin City

流域生态环境需水量是生态系统的一项指标,是指在一般情况下流域生态系统本身能够通过自我调节来保证并维持生态环境的质量平衡以及其他基本功能正常的最小需水量。流域生态环境需水量按照河道的范围可以划分为两个部分,即河道内生态环境需水量和河道外生态环境需水量,因此在计算的过程中要分别确定这两个方面需水量的计算范围和计算公式。研究以桂林市桃花江流域生态环境为例,对相关的概念进行相应的介绍,并以科学的理论公式(主要是面积定额法和Tennant法)对该流域实际的生态环境需水量进行计算。通过计算分析,桃花江流域河道内、外生态环境需水量分别为0.901亿m3和0.146亿m3,分别占流域年均径流量的26.8%和4.3%。因此,应通过科学管理及提高利用效率等方式,将该流域范围内工业及生活用水总量控制在年均径流量的68%以下,以保证桃花江流域的生态环境安全。

The eco environmental water demand of basin is an index of ecological system, which means the basin ecological system can guarantee and maintain the quality balance of ecological environment and the min- imuru water demand of other basic functions by self-regulation under the common circumstances,. The eco- environmental water demand of basin can be divided into two parts based on the river range, namely, the in- side eco-environmental water demand and the outside eco-environmental water demand. Therefore, in the process of calculation, the calculation range and formula of the water demand should be confirmed respective ly. This study takes the eco-environment of Taohuajiang basin of Guilin City as an example to introduce some relevant concepts and calculate the practical water demand based on scientific theoretical formula （primarily the area quota method and the Tennant method）. It can be known that the inside and outside eco environ mental water demand of Taohuajiang basin are 90.1 million m^3 and 14. 6 million m^3, respectively, which are 26.8% and 4.3% of the average annual runoff volume, respectively, according to the results from analysis and calculation. Therefore, in order to ensure the eco-environmental security of Taohuajiang basin, we should control the total amount of industrial and domestic water below 68% of the average annual runoff.