叶尔羌河下游河岸林草耗水分析

Analysis on water consumption by forest and grass in lower reach of Yarkand River

叶尔羌河是塔里木河的主要源流之一,研究下游河道水量平衡与河岸林草耗水对于流域水资源配置具有重要意义。本研究从地下水与植被状态的关系出发,建立反映河道输水损失及水分转化规律的水量平衡模型,同时耦合潜水蒸发与地下水运移模型,构建河岸林草耗水模型,以此分析2000—2020年的叶尔羌河下游河岸林草耗水。结果表明:叶尔羌河下游河道水量损失主要是渗漏损失,占总损失量的95%;该区域林草耗水多年平均值为128 mm,其左岸多年平均耗水量为226 mm,大于右岸的93 mm。该模型能较好地计算叶尔羌河下游的河道水量平衡以及河岸林草耗水量,可应用于依赖于河道渗漏补给的西北内陆河流的河岸林草耗水分析。

The Yarkand River is one of the main tributaries of the Tarim River. Understanding the water balance in its lower reach and the water consumption by riparian forests and grasses is greatly significant to the allocation of water resources in the basin. This paper develops a water balance model to describe water loss and water transformation and their variations based on the relationship between groundwater and vegetation. A phreatic water evaporation model and a groundwater transport model are coupled to construct a water consumption model of riparian forest and grass that is applied in a case study of the lower Yarkand River in 2000-2020. The results show that in this reach, most of the river water loss comes from leakage, which is more than 95% of the total water loss;multiyear average water consumption by forest and grass is 128 mm, with the left bank of 226 mm that is greater than 93 mm on the right bank.This model gives satisfactory calculations of the water balance components and the water consumption by forest and grass for the study river reach, and thus it would be applicable to other northwest inland rivers where riparian froest and grassland depend on river leakage recharge.