Predictive Analysis Of The Effect From The Storage And Drainage Works On The Groundwater Environment In Dingbian County

The topography of Dingbian county is flat with no river crossing this area.There is nowhere for the life sewage of this county to row,whose consuming can only be done through natural evaporation and infiltration.The sewage infiltration seriously affected the local groundwater environment quality.Thus,it is practically significant for the construction of the storage and drainage works,which is engaged to solve the problems of losing water and Indiscriminate discharge of sewage.Based on the analysis and research of the hydrogeological environmental background and the research results,and the hydrogeological experiment,this thesis dispersion makes a dispersion test using NaCl as tracer in brackish water areas for the first time and calculates the dispersivity of aquifer,providing basic data for the constructing of groundwater numerical model.This thesis also identifies and verifies the constructed groundwater numerical model by using the related material like simultaneous measurement of groundwater,and forecasts the groundwater environment at different stages after the running of drainage project using the recognized and validated numerical model.After the operating of storage and drainage works,the underground water level is predicted to rise no more than 0.5 m,having no effect on Maliantan headwater and Mahua Pond;the influence for the water level of the wells of surrounding villages closed to storage and drainage works is no more than 0.1 m,not affecting water withdrawals of residents;the engineering of storage and drainage works will lead to soil secondary salinization,the mild and moderate salinization area increased by 8%and 8%respectively compared to the current situation,so the influence is less.After the operation of storage and drainage works,pollutants in the high and low pool(channels),and the east and west lake areas form high value region,dispersing around the center of high value region with concentration gradually decreases.These pollutants impact the drinking water of about 4000 people from six villages and the groundwater quality of Gouchi salt lake area.The main performance is the increase of predictive factors concentration of different water quality,most ly reaching IV class water standard.For the soil salinization problems caused by the operation of storage and drainage works,this thesis puts forward to reduce the soil salt and strengthen drainage storage seepage-proofing;as for problems of residents water quality,the suggestion of delivering 26m3/d water from the unpolluted area for residents living in the water quality affected area is proposed;for Gouchi and wetland water quality problems,this thesis advances to carry out the "rain dirt separation" drainage policy,which drains away the sewage into the high and low pool,the storm-water into wetland in order to protect the wetland and prohibits sewage from discharging into the west lake.