河套灌区出让水权对天然植被影响研究

Research on the Impact of Transferring Water Rights in Hetao Irrigation Area on Natural Vegetation

为深入研究河套灌区通过节水改造进行水权交易对灌区生态环境的影响,利用遥感和实测数据相结合的方法,探究沈乌灌域节水改造前后归一化植被指数NDVI与地下水埋深之间的关系,确定沈乌灌域地下水埋深不宜超过3.4 m。同时,基于MIKE SHE模型平台构建沈乌灌域分布式水循环模型,利用地下水观测井数据、地下水流场和排水沟监测流量完成参数率定和验证。利用模型对现状总引水量3.06亿m^(3)情况下的地下水埋深进行预测,预测结果表明,到2025年将有50%的区域地下水埋深超过3.4 m,到2030年将有78%的区域地下水埋深超过3.4 m。结合地下水埋深与NDVI之间的关系,可以推断沈乌灌域植被生长状况将受到严重影响,应针对现状取水提出生态补水方案。

In order to conduct in⁃depth research on the impact of water rights trading through water⁃saving transformation on the ecological environment of irrigation areas.This study used a combination of remote sensing and measured data to establish the variation pattern of vegeta⁃tion normalized vegetation index(NDVI)and groundwater depth before and after water⁃saving transformation in the irrigation area.It was de⁃termined that the suitable groundwater depth for the Shenwu irrigation area should not exceed 3.4 meters.Meanwhile,based on the MIKE SHE model platform,a distributed water cycle model for the Shenwu irrigation area was built,and parameter calibration and validation were completed by using groundwater observation logging data,groundwater flow field,and drainage ditch monitoring flow rate.The model was used to predict the groundwater depth under the current total diversion of 306 million cubic meters,and the prediction results show that by 2025,50%of the areas will have groundwater depths exceeding 3.4 meters;By 2030,78%of the areas will have groundwater depths excee⁃ding 3.4 meters;Based on the relationship between groundwater depth and NDVI,it can be inferred that the vegetation growth status in the Shenwu irrigation area will be severely affected,and an ecological water replenishment plan should be proposed based on the current water in⁃take situation.