Study On The Effect Of Fenhe Storage Progect On Groundwater Seepage Field

With the ecological construction developing, many cities have afforested riverway through the city proper. For setting green city image, The government of Taiyuan city has beautified the Fenghe park as the first stage project which had build four rubber dam in riverway forming three reservoir where water lever was 1-3m higher than that of before. Now, the second stage project is ready to stretch 2.4 km to the north and 5.7km to the south similar to the first stage project.Usually, groundwater movement in the city proper recharges Fenhe River. Characteristics of groundwater seepage field will be changed after riverway is stored water, ground water lever in the city could rise, which will result in a series of environmentalproblems, such as soil salt basification, swamping and immerging of city's building base.To forecast the changes of groundwater seepage after construction of the second project, the author contrasted and analyzed the effects of no imperious wall disposal, imperious wall disposal, hanging-style imperious wall disposal and stability of the reservoir's bottom layer on the reservoir's seepage quantity and groundwater level of the city proper. The numerical model is established and used to simulate the groundwater seepage field in project area under different conditions.After stored water in Fenhe River, great hydraulic gradient would be formed between reservoir and groundwater. It is not reasonable to ignore the vertical moving of groundwater. Therefore, three dimensional flow model is applied in the study to simulate groundwater movement. During calculating, the author adopted horizontal-flow barrier (HFB) to simulate the imperious wall, which made it more objective to reflect seepage characteristics. PCG2 iterative method, which takes into account convergence of both cell flux and water head, is used in the paper.After calibrating and verifying the model, we can draw the conclusion that the mathematic model was correct, and the generalization of the hydrogeological conditions and the parameters are reasonable.The author Apply this model to calculate the reservoir seepage field, seepage quantity and the increase of water lever under deferent conditions one year later the project running. The results indicated that it is most severe of reservoir seepage when there is no imperious wall, Also bringing large-scale immerging problems in the city; The function of hanging-style imperious wall is very poor; The closure-style imperious wall could notably reduce seepage quantity and substrata immerging incidence and it was recommended to be the most perfect design.