西部干旱区生态需水的规律及特点——以塔里木河下游绿色走廊为例

天然植被蒸散耗水量小，水分有效利用程度高，生态需水可塑性及水质变幅较大等是生态需水的主要特点．保护塔里木河下游绿色走廊的生态需水量，主要是指大西海子以下自然植被的需水量．即地下水位恢复总水量和全河段生态总维持水量，前者主要包括水位恢复水量、侧向排泄量及河道蒸发水量．2005年泄水目标为阿尔干，生态总需水量为恢复大西海于至阿尔干地下水的总水量，该水量为13．20×10^8m^3，年均需水量为2．64×10^8m^3．2010年泄水目标及植被保护目标都是台特玛湖，生态总需水量包括恢复阿尔干至台特玛湖段地下水位的水量以及维持大西海子至台特玛湖段生态的维持水量，该水量为18．32×10^8m^3，年均需水量为3．66×10^8m^3．2010—2030年的生态总需水量包括每年维持大西海子至台特玛湖段生态的总维持水量，同时也包括增加植被18．67×10^4hm^2所需要的水量，20年生态总需水量为139．00×10^8m^3，年均需水量为6．95×10^8m^3．通过一系列措施保证生态用水，是干旱区生态建设的关键．

Patterns and characteristics of ecological water demand in west arid zone of China-A case study of green corridor in the lower reaches of Tarim River

Ecological water demand has some characteristics. The ecological water demand that was used for protection of the green corridor in the lower reaches of Tarim River was chiefly water demand by natural vegetation below Daxihaizi reservoir, and it included gross restoration water amount of ground water level and gross stand water amount in all over the lower reaches of Tarim River. The gross restoration water amount of ground water level mainly included restoration water amount of ground water level and lateral discharge, as well as evaporation of the course. Based on the drainage target of Alagan in 2005, gross ecological water demand was the gross water amount of restoration ground water level between Daxihaizi and Alagan, which would be 13.20 x 10(8) m3. Meanwhile, the annual average water demand would be 2.64 x 10(8) m3. Because the drainage target and vegetation protection target would be all Taitema lake in 2010, the gross ecological water demand included not only the gross water amount of restoration ground water level between Alagan and Taitema lake, but also the ecological stand water amount between Daxihaizi and Taitema lake, which would be 18.32 x 10(8) m3. Meanwhile, the annual average water demand would be 3.66 x 10(8) m3. From the year 2010 to 2030, the gross ecological water demand would be consisted of two parts (the gross stand water amount between Daxihaizi and Alagan, and the water demand by increased vegetation of 18.67 x 10(4) hm2), and the total ecological water demand during the 20 years would be 139.00 x 10(8) m3. Meanwhile, the annual average water demand would be 6.95 x 10(8) m3.