Simulation Of Flood Storage By Grit Pit Effects On Groundwater At Western Suburb Of Beijing

Water resource is one of the most important resources for human life.With the increase of population and the development of human society,the worsening environment and water pollution,which caused by both natural factors and human factors,are making available water gradually decline;on another face,elimate change to extreme weather appeared again and again,let the trend of the uneven distribution of water resources further.Groundwater is an important part of water resource,Increasingly shows the importance of groundwater for human survival and development.The Beijing municipal government and relevant units started flood storage project that planning for many years in the western suburbs for responding positively extreme precipitation weather and reducing the influence on urban flood and regulation and storage urban groundwater resources.This paper was supported by related research subject of the project in the western suburbs of Beijing.The content of the article is analyzing the influence of the short covering of flood storage on the levels and quality of groundwater,and this study on prediction by numerical simulation method.Firstly,On the basis of mastering the theory by collecting and analyzing data modeling of conceptual hydrogeological.Secondly,the groundwater simulation model was built by reasonably generalized boundary conditions sinks and sources and to let numerical model reach used precision by recognizing and verifying model parameters based on actual groundwater flow field.The flood storage effects degree and scope on groundwater level and water quality was predicted by running model and building solute transport models.At last,the sensitivity algorithm is used to calculate the sensitivity coefficients of the parameter of multiple models.According to the computing result compare the degree of influence of change of different parameter on the predicted results of models.We got the following understanding through the analysis of predictions and sensitivity coefficient of model parameters calculation results:(1)The results show that,the biggest rise in groundwater is 7.89 m and 9.79 m respectively after reservoir impoundment under the condition of two kinds of groundwater exploitation;and around the reservoir area of more than 0.5m of water level rise is 2.39 km2 and 6.2 km2,and groundwater level is lower than limit water level(2)Around the reservoir area of groundwater solute concentration assume after the first high low development process with the infiltration of the flood.The solute concentration in the groundwater rise rapidly during initial period and solute concentration began a significant reduction in groundwater due to the decrease of the concentration and dilution effect of groundwater in the middle and late period(3)Through the analysis of the sensitivity of model parameters,the model predictions of the flow parameters are most affected permeability,followed by water level,rainfall infiltration coefficient,canals infiltration coefficient;while in solute transport model,the change in the amount of solute with respect to the impact of vertical dispersion degree of the simulation results to be greater.The results obtained above,a feasibility study for the project construction and post-operation provided.