The Study On The Groundwater Level Recovery To The Water Release And Ecological Water Requirement In The Lower Reaches Of Tarim River

The ground water is important to sustain the ecological environment in the arid inland. In the article which is referred to the research of urgent ecological water release in the lower reaches of Tarim River, the rule of the groundwater movement is analysed according to the observed groundwater level. The water amount which seeps from the river to the unsaturated and saturated zones is quantified by the traditional simplified analytical method. On the base of groundwater level calculated in Visual Modflow, the digital groundwater depth model is obtained by using the concept of Digital Terrain Model, and the difference of groundwater depth before and after the water release is obtained as well. At the last part of the article, two phases of improving the ecological enviromnet is put forward and the ecological requirement water amount is calculated in both phases.The analyses shows that the groundwater level rises during releasing water and groundwater level decreases when no water in the river. The range of groundwater change is different due to the distance from the river. The calculation results indicate that most the water in the river seeps underground, 53.25% of the water seeping underground is evapotranspired and the other water seeping underground is recharged to the aquifer, as a result the groundwater level increases. Before releasing water the area in which the groundwater depth is between 0 to 8 meters is 316km2, and after releasing water is 611.34km2. In the phase of recovery the water released of 28.88× 10~8m~3 will be required and in the phase of maintaining the water released of 1.41 × 10~8m~3 will be required every year.