长江上游地区生态需水量变化研究

Study on change of eco-water demand in region of upper Yangtze River

生态需水是生态用水控制和区域生态环境恢复的基本依据和关键。为了确保流域生态系统健康发展,实现水资源合理配置,基于GIS技术与水文气象实测数据等,采用Tennant法计算研究区河流生态需水和Penman-Monteith法计算植被生态需水。结果表明:长江上游地区河流生态需水量为1022亿m^(3),植被生态需水量为4668.43亿m^(3)。研究区1981—2007年年均生态需水量呈下降趋势;水资源二级区中,金沙江石鼓以下生态需水总量最大,为1349.90亿m^(3),乌江生态需水总量最小,为562.73亿m^(3)。各植被类型需水量由大到小依次为水田(1564.62亿m^(3))、林地(1460.30亿m^(3))、灌丛(1231.91亿m^(3))、草地(397.22亿m^(3))、旱地(14.64亿m^(3))。研究区植被生态需水主要集中在5—8月,占植被整个生长季全部需水的63.78%,河流生态需水主要集中在6—10月,占河流全年总需水量的74.50%。研究结果可为内陆河区域的生态需水量的合理配置提供科学依据,为流域生态环境保护提供理论支撑。

Eco-water demand is the basic basis and key link of eco-water use control and regional eco-environment restoration.In order to ensure the healthy development of the ecosystem within the river basin and realize the reasonable allocation of water resources,the river eco-water demand in the study area is calculated with Tennant method and the relevant eco-water demand of vegetation cover is calculated with Penman-Monteith method on the basis of the measured hydrometeorological data and GIS technique.The results show that the river eco-water demand is 102.2 billion m^(3) with the vegetation eco-water demand of 466.843 billion m^(3) within the region of the upper Yangtze River.The annual mean eco-water demand in the study area exhibits a decreasing trend from 1981 to 2007.Among the secondary water resources regions,the total eco-water demand below Shigu section of Jinshajiang River is the largest with the demand of 134.990 billion m^(3),while the total eco-water demand of Wujiang River is the smallest with the demand of 56.273 billion m^(3).The water demands of all the vegetation types from large to small are paddy field(156.462 billion m^(3)),woodland(146.030 billion m^(3)),shrub(123.191 billion m^(3)),grassland(39.722 billion m^(3))and dry land(1.464 billion m^(3))in turn.The vegetation eco-water demand in the study area is mainly concentrated in the period from May to August,accounting for 63.78% of the total water demand of the whole vegetation growing season,while the river eco-water demand is mainly concentrated in the period from June to October,accounting for 74.50% of the total water demand of the river in the whole year.The study results can lay a scientific basis for the reasonable allocation of the eco-water demand in arid and semi-arid inland river regions and provide theoretical support for the eco-environment protection of the river basin.