Analysis And Evaluation Of Immersion In Chenpingpu Auxiliary Dam Of Shifosi Reservoir

Reservoirs serve the function of flood control,power generation,irrigation,water supply,aquaculture and other functions.However,when the reservoir is put into operation,with water level rising,the groundwater level increases,the surrounding immersion of reservoir highlights.Due to soil physical properties,groundwater level changes and other reasons,the growth of plants will be affected--wilting or even die.And the foundation of buildings will be destroyed.In this study,the immersion area of Shifosi reservoir was study object.The mechanism of immersion in this region is analyzed synthetically,and the immersion boundary is preliminarily delineated.Using groundwater simulation software to establishthe groundwater numerical model of the study area,and predict the change of groundwater level under different water level.The evaluation system of immersion hazard was established,combined with gray clustering evaluation model,to evaluate the immersion disaster in the study area.The system incorporates a variety of evaluation indicators,which enhances the objectivity of the evaluation results,and provides a reasonable basis for the future treatment of immersion areas.The main research conclusions are as follows:(1)The water level of the Lama River is observed by the water ruler.And the correlation between the reservoir water level and the river water level is analyzed.The result shows that the backwater phenomenon caused by reservoir water storage has obvious effect on the water level of the Lama River,which is one of the reasons of the immersion;By the soil sample collection on both sides of the river,the soil moisture content was analyzed,the topography affects the extent of the immersion;The correlation between the groundwater level and its influencing factors in the submerged area is analyzed to obtain correlation ranking(from large to small):Water level>Air temperature>Rainfall>Evaporation>Wind speed?The analysis of the current situation of submergence in the study area can provide reference for the establishment of reservoir immersion evaluation system and immersion evaluation.(2)Based on the three-dimensional groundwater simulation software,the three-dimensional geological model,the study area was constructed by using the drilling data extracted from the geological profile of Shifosi reservoirand the drilling data generated by the interpolation method.After the grid segmentation,the soil data parameters are imported to get the groundwater numerical model.The model is used to calculate the groundwater level of the submerged area under different reservoir water level after check and correction.According to the criteria of immersion judgment,when the water storage level is 46.2 m,the area of severe submergence in the study area accounts for more than 85%of the total area of the study area,and the immersion disaster is serious.At the same time,the calculated water level data can be used as information on the comprehensive evaluation parameters of the immersion area.(3)In allusion to evaluate the single factor of immersion,the factors related to crop growth(water content,natural porosity ratio,saturation degree,etc.)were used as evaluation indexes in this study.Quantitative standards of each factor were designed.System was established according to Analytic Hierarchy Process.The hazard of immersion was evaluated by Gray Evaluation Method of Whitening Weight Function.According to the evaluation results,the immersion disaster of the immersion area was serious,and the soil in the area was not suitable for crop cultivation.The results can provide the basis for the reasonable compensation and treatment of the immersion area.