Abstract:
A transient groundwater flow model was constructed for the North Plain of the Urumqi River Basin using the conceptual model approach.This model was connected to the Chaiwopu and River Valley model with a flow boundary at the interface.These two models together form an integrated model for simulation and analysis of water resources development in the Urumqi River Basin.The North Plain consists of two main hydrogeological units: the southern piedmont fans and the northern alluvial plain.The piedmont fans consist of thick sand and gravels,and the alluvial plain consists of multi-layers of sand,silt and clayey sand.Under the natural conditions,groundwater receives recharge mainly from river leakage and lateral inflow from the piedmont fans,flows northward,discharges in the from of springs at the transition area from the piedmont fans to the alluvial plain and to the northern desert.Recently,hydrogeological cycle has been altered by artificial activities.Irrigation return flow becomes an important recharge component and abstraction of groundwater becomes a dominant way of discharge.Seasonal abstraction for irrigation causes large temporal seasonal variations in groundwater levels.The decrease in groundwater levels by abstraction reduces the evapotranspiration,therefore,mitigates the salinity problem caused by irrigation.