| Tarim River basin,1 321km in length and total area of stream basin of 102×104km2,is the largest continental river. Western and eastern downstream is Taklimakan and Kuluk deserts,in which alluvial fans is located. For some years, owing to significant reduction of main stream's water flow,and main stream irrationality exploitation,consumpution increasing rapidly in upper and middle stem,water flow decreased from 12.4×108 m3 in 1960s to 2.7×108m3 in 1990s, main stem downstream of 358 kilometer from Daxihazi Reservoir cut off for a long time.XinjiangConservancy department, Tarim River basin department and Xinjiang people's government towards ecological and environmental problems,started to launch to transport water to downstream from 2000, in order to save downstream"green corridor" dying out .until now,ten times transporting water have finished,preceding nine times transported about 22.2×108 m3, total conveyance 945 days. This paper uses three different methods to simulate groundwater changement,and come to conclusion:(1)C5 and C6 wells are simulated with BP Neural Networks and tested,maximum error are 0.39 m and 0.36 m respectively.Precision request has be settled for,and groundwater level in 2010 year is predicted through different transporting water quantity and transporting water days.The prediction results indicate:(1)when transportion water quantity is 1×108 m3,tansportion time is 30 days and 60 days,grounwater level of C5 well is 829.665m and 829.775m respectively;C6 well is 829.393m and 829.463m;(2) when transportion water quantity is 2×108 m3,tansportion time is 30 days and 60 days, grounwater level of C5 well is 830.175m and 830.335m respectively;C6 well is 829.753m and 830.053m;(3)when transportion water quantity is 3×108 m3,tansportion time is 30 days and 60 days, grounwater level of C5 well is 830.515m and 830.605 m respectively;C6 well is 830.313 m and 830.323 m;(2)Groundwater non-steady movement when river leakage exists in one side in the Yingsu section in the lower reaches of Tarim River is simulated from groundwater kinetics,and results is close to true vule,C5,C6,C7,C8 well mean absolute error is 0.447,0.334,0.248,0.467,and root mean square error is0.07,0.049,0.043,0.091,maximal error is C8 well due to its terrain elevation is low,and evaporation capability is strong.In total,analytic method is feasible on simulating groudwater level movement in the lower reaches of Tarim River.(3)Groundwater level changement is simulated numerically with Visual Modflow 3.1,groundwater calculation vule fits well with true vlue,dedicacy analysist indicates hydrogeologic parameters change steadily.Until now after nine times transporting water,the result is:remarkable affecting area through transporting water is about 2 km away from riverway.seven times transporting water impact on groundwater level notably,the eighth time and ninth time was longer than one year with the seventh.During that time,groundwater level is high and evaporation period is long,so rise extent is not great after transporting water.C5 and C6 observation well were affected intensively as a result of transporting water,grounwater level exceed 830 m for a long time,and its vertex was 832m,the vertex of C7 and C8 were close to 830m,and affection is small.Two years after nine transporting water,groundwater level falls continually,and maximal declining value is 1.09 m because of without transporting water and intensive evaporation.
|
PDF Full Text Request