Research On Hydrogeolocial Parameter Test By Distributed Temperature Sensor And Forecast Of Groundwater Level By Ensemble Kalman Filter

Water crisis in arid and semi-arid regions is a worldwide problem, not excludingthe Northwest region in China. How to use the limited water resources reasonably andefficiently is a focused topic by water resources managers and researchers. One of keyissues is where to store the limited water resources. Since years, the water resourcesmanagers preferred to store water in the surface water reservoirs. It is conviniet tostore and divert. However, due to its characteristics of high evaporation in the arid andsemi-arid region, the way of storing water in the surface water reservoir resulted inunvaild losses of water resources. Under this background, the researchers brought outthe idea of groundwater reservoir. It is to store water in the underground in order todecrease the unvalid evaporation losses while the total amount of usable water isincreased.The groundwater reservoir concerns many research contents, such as location ofthe groundwater reservoir, volume design, water resources assessment, etc. In thisthesis, the Chaiwopu Basin including river valley located in the Urumqi River Basinin Xinjiang Province is chose as the research area. Four aspects of research contentswere carried out and conclusions were drawed:①the feasibility of groundwaterreservoir is analyzed from geological structure, hydrogeologicalconditions, conditions of water resources. It is concluded that the UrumqiRiver runoff area in the Chaiwopu Basin is suitable for the construction of a naturalunderground reservoir,②Using the technique of Distributed Temperature Sensor(DTS), the temperature variation process in the shallow layers of riverbed inChaiwopu Basin is moinotored under the recharge mode. The basic characteristicsof flow and the thermophysical properties of riverbed sediments were analyzedqualitatively. Under the vertical recharge mode, water moves mainly downwards inunconsolidated sediments. With the increase of depth, horizontal flow of wateroccurred while its influenced range is quite limited. In addition, the thermalconductivity of sediments in shallow layers of the Chaiwopu Basin is good, while thethermal dispersion capability is poor.③According to the flow and heat transport modeling and monitored temperature data, the riverbed hydrogeological parameters ofshallow layers are calibrated and obtained. After model calibration, the horizontaland vertical permeability of the testing area are1.48×10-4m/s and1.34×10-5m/srespectively.④The Ensemble Kalman Filter (EnKF) and numeric simulation arecoupled in groundwater level prediction. Theretically and practically, EnKF is provedto be an effective method to improve the accuracy of model prediction.