堤防修建对塔里木河中游湿地地下水化学特征及水盐运移的影响

Variations in Groundwater Chemistry and the Movement of Salt Infuenced by the Dikes in the Wetlands of Middle Reaches of Tarim River

通过对塔里木河中游输水堤防修建之初以及修建5年后,沙子河口、乌斯满和阿其河口三个断面地下水化学特征时空变化的监测与分析,初步揭示了在输水堤防影响下地下水化学特征变化的初步规律,结果表明:(1)在空间上,沙子河断面地下水化学变化规律完全被颠倒过来,乌斯满断面,地下水化学变化规律受输水堤防的影响不十分明显,但地表积盐严重;阿其河断面,则呈现复杂的变化.(2)在时间上,丰枯期地下水化学特征的正常变化规律在沙子河被彻底改变,在乌斯满和阿其河呈现出复杂变化.各化学组分含量在沙子河断面和乌斯满、阿其河断面的含量及其变化特点与断面间的环境条件的差异显著相关,沙子河断面自堤防修建后就没有地表水经过,而设有生态闸的乌斯满和阿其河断面的一定范围内在洪水期还有地表过水;而以矿化度为代表的水化学特征表现为随着年份的增加而上升的特点.(3)从水力联系上,堤防修建之初,距堤防1500m左右范围以内各处的水化学特征具有显著相关性,水盐排泄区在1500m左右的区域.5年后只有距800m以内范围各处的水力联系尚在,而且800m处成为水盐排泄区,沿河淡化带的萎缩必将带来植物群落的退化和湿地面积的缩小.

To reveal the influence of embankment to groundwater hydrochemical, where suffering flood before the embankment being built,a set of data of groundwater hydrochemieal were obtained over 3 years. The primary regulation of groundwater hydrochemical variation is delivered, that is the spatial influence of embankment to groundwater hydrochemical limits in 1 000 m at Shazihe Sector ,and 2 000 m at Wusiman Sector,the variation of mineralized degree and alkalinity were significant comparing to the period of embankment not being built at Shazihe Sector, At Aqihe Sector, the variation of groundwater hydrochemical is complex causing by embankment. The variations of hardness of groundwater between flooding and wilt period of Tarim River, is complex at Shazihekou Sector,the hardness in flooding period is higher than that in wilt period except the sample well 2 000 m to watercourse at Wusiman Sector. At Aqihekou Sector,the hardness of groundwater is lower in flooding period than that in wilt period except the sample well 100 m to watercourse. The mineralized degree of groundwater showed a complex change between flooding and wilt period at Shazihekou Sector. In general, the mineralized degree of groundwater is lower in flooding period comparing to wilt period at both Wusiman Sector. and Aqihekou Sector. The content of Cl^- in flooding period is higher than in wilt period at Shazihekou Sector and Wusiman Sector, but it is the opposite at Aqihe Sector. Total dissolved solids （TDS）, the representative of groundwater chemistry increased year by year due to the influence of the dikes. At the beginning of the dikes being built,the diluted belt along the river was about 1 500 m or so from the dikes,and which became 800 m or so after 5 years later. The great changes of the salt movement will result in the degradation of vegetation in the study area.