Effects Of Ecological Water Transportation On Groundwater Changes And Populus Euphratica Growth Of The Lower Reaches Of Tarim River

The "Green corridor" consists of desert riparian forests located around the lowerreaches of Tarim River has been declining since1950s.After the construction ofDaxihaizi Reservoir by1972, the lower reaches of the river ran dry, exacerbating thetrend of deterioration of ecological environment of the "green corridor". In order torepair the severely damaged riparian forest ecosystems, control the desertificationspeed, the Chinese government invest large sums of money to carry outcomprehensive management of Tarim River, and since2000implemented theecological water transportation project to the river route which had ran dry morethan30years. Until2011, totally finished twelve times of ecological watertransportation, the cumulative water delivery capacity reached2.7×10¹⁰m³, makethe riparian forest groundwater conditions have a significant change.In this paper, two main contents are included. First, the groundwater change afterthe ecological water transportation in the lower reaches of Tarim River; Second, theresponse of Populus euphratica to water transportation. twelve times of ecologicalwater transportation as the research background, take Yingsu, Arghan, Yiganbujima asthe main research section, make an analysis on the run off changes, time of changes,groundwater depth, groundwater quality of each section based on groundwater datamaterials of above three section. Populus euphratica growth response to the watertransportation,4500Populous tree height, diameter at breast height, crown, branchesof Higher in Arghan section were measured, high-level analysis of different tree, theDBH class of P. euphratica water transportation response;2005-2011determinationof poplar height, diameter, crown vigor index data were analyzed, mainly Populouseuphratica growing index changes observed after ecological water transportation. Thegroundwater level and Populous absolute tree, green tree height, diameter at breastheight, crown width, branch under higher ecological indicators, correlation analysis, to draw the relationship between groundwater change and Populous euphraticagrowth.The results show that, because the distance between Daxihaizi and Yingsu is soclose, it makes the runoff of Yingsu continuous and the total runoff higher than theother two sections. It Can also be drawn from the water flow changes of each sectionthat the water flow time of Yingsu is the longest between Yingsu, Arghan andYiganbujima. from the first water transportation in2000to the twelveth in2011, thetotal number of days of the flowing water is1209, from the overall changes of waterflow duration, the flow time of eleventh and twelfth is the longest, takes26%of totaltime.It can be seen that the last two water delivery in June2010to November2011since the implementation of artificial water delivery to the Tarim River, is the longest,continuous twice conveyance. Each section showed a different variation of thegroundwater depth at different distances from the river, the conveyance, before2007,the2011section groundwater table can be seen with the change in distance from theriver, with the conveyance number of increase the groundwater level trend of uplift;Arghan section runoff and monitoring wells, water depth showed a negativecorrelation; As each section of monitoring wells from the river distance, so themonitoring well water depth showed also different trends. Groundwater qualitychanges after water analysis results show that groundwater salinity, groundwater pHvalue changes with increasing distance from the river increases; and water transfer isproportional to the number of lost water.After ecological water transportation, downstream of Tarim River Arghanhigh-level cross-section of different tree, different DBH-class distribution of Populousare quite different. in diameter≤4cm at breast height saplings distributed in nearriver areas, especially away from the river within20m.Tree height is3.0<X≤9.0mPopulous dominant in the study area have number of trees. Tree taller than9.0m Populous more evenly distributed from the river within adistance of300m,300m outside the distribution of scarce; in the study area, DBH<36cm Populus trees accounted for most of the features. Populus euphratica growingindicators of change analysis, from the seventh conveyance in2005to2011, thetwelfth conveyance five transportation processes, the high the Populus green treediameter at breast height, crown width, and other indicators show growth trend can beseen from ecological water conveyance role in promoting the recovery of downstreamvegetation.