Research on Ecological & Environmental Water Requirement for plain regions of Tailan River in Xinjiang

生态环境需水是生态水文学中的一个重要研究课题。本文选择新疆台兰河流域平原区作为研究对象，对该区域的生态环境需水进行系统研究，主要研究内容与结论如下：（1）基于当前生态环境需水研究基础上，依据台兰河平原区生态系统特性，构建了台兰河平原区生态环境需水量的理论框架及量化模型： W（区域或流域生态环境需水量）= Wt（天然植被生态环境需水量）+Wr（河流生态环境需水量）+ Ww（湿地生态环境需水量）+Ws（防治耕地盐碱化环境需水量）—Wre（重复计算量）。该模型在生态环境需水量计算中充分考虑了河流水质自净、输沙需水量、河道渗漏需水量以及防治耕地盐碱化需水量，具有一定的可操作性和可行性。（2）根据所建模型，对台兰河平原区生态环境需水量进行计算，得出最大生态环境需水量为4.146×108 m3，最小生态环境需水量为2.372×108 m3，最适生态环境需水量为2.983××108 m3，分别占台兰河平原区水资源总量的51.05%、29.21%与36.73%。结果表明台兰河平原区水资源开发的潜力不大，要实现区域的可持续性发展，必须确保达到生态系统和社会系统耗水各占50%的最低耗水状态。（3）河道内的生态环境用水属于可控制生态环境用水（如输沙需水量的人工调配），在水资源合理配置中，必须优先满足。在不考虑河流输沙需水量的情况下，台兰河河流生态环境需水量为1.440×108 m3。在考虑输沙需水量的情况下，河流生态环境需水量为2.603×108 m3。（4）生态环境需水量的时空分异研究表明：时间上，台兰河平原区生态环境需水量年内变化强烈，4月至9月为主要生态环境需水时间，占全年总需水量的80%以上，最大生态环境需水量出现在7月（4395.72×104 m3），最小为12月（623.15×104 m3）；空间上，单位面积生态环境需水量处于700 m3/hm2水平的所占面积最大，主要以中覆盖度草地与灌木林地为主。（5）水平衡分析结果表明，基于最大与最小生态环境需水量时，在两种频率（P=50%，P=75%）的来水情况下，均有不同程度的缺水，且缺水主要集中在3、4、5、6、9及11月，这与现状调查的结果台兰河流域春秋干旱频繁是一致的，其中缺水量最大值基本上出现在4月，缺额在3000-4000×104 m3左右。当基于最小生态环境需水量时，各水平年供需情况表现为总水量上余额，当基于最大生态环境需水量时，则表现为总水量上缺额。Ecological water requirement is one of the important research topics in Eco-hydrology. Thus, this paper chose Tailan River as an object in order to study its regional ecological water requirement systematically. The main contents and conclusions are as follows: (1) On the basis of current researches on eco-environmental water requirement and ecosystem characteristics accordingly, this paper established the academic frame and quantitative model. It is W= Wv+ Wr + Ww + Ws- Wre. (2) According to the model, this paper calculated the eco-environmental water requirement in research region. Outcomes are that the maximum eco-environmental water requirement is 4.146×108 m3, the minimum is 2.372×108 m3 and the optimum is 2.983××108 m3, which take 51.05%、29.21% and 36.73% of the regional water gross respectively. These results indicate that such region has some certain potential in development, but, it is a little. In order to carry out regional sustainable development, it must make sure that ecological and social system account for 50% of the regional water gross respectively, which is the lowest water expending state. (3) Beacause eco-environmental water requirement in riverway belongs to controllable parts(taking water requirement in sand transportation for example), it must be satisfied firstly. Eco-environmental water requirement in Tailan River is 1.440×108 m3, without considering the ones in sand transportation, 2.603×108 m3 Contrarily. (4) Variabilities in space-time indicate that eco-environmental water requirement in Tailan River changed greatly inner year. The main time is from April to September, which account for 80% more, the max is in July (4395.72×104 m3), and the min is in December (623.15×104 m3); eco-environmental water requirement per unit area which is 700 m3/hm2 takes the biggest ratio. (5) Water balanceable results indicate that eco-environmental water requirement in Tailan River is in deficiency in different degrees when analyses it base on 50% and 75% frequency. The main time is March, April, May, June, September and November and the maximum deficiency is in April on the whole (3000-4000×104 m3). Total water demand-supply in common years is surplus when calculate on minimum eco-environmental water requirement. It is deficient when calculate on maximum eco-environmental water requirement