| The South-to-North Water Transfer Project can alleviate the serious water shortage in northern China, achieve rational allocation of water resources, guarantee sustainable development of economy, society and population, resources and environment. The eastern route of South-to-North Water Transfer Project supplies water to the eastern of Huanghuaihai Plain as an important part of South-to-North Water Transfer Project. 2013, the eastern route of South-to-North Water Transfer Project was with the full range of water conditions, four water transfers had been completed by June 2015. Because of the long period of high water level, the supplying and draining relationship between the original river and the groundwater will be changed, which will change the situation and the groundwater flow in the area river flowed along.In this paper, the eastern route of South-to-North Water Transfer Project of Nansi Lake to Dongping Lake is the study area, and the LiangJi Canal and LiuChang River are the main objects. This paper made a quantitative analysis on the water exchange between river and groundwater, and forecasted the variation tendency of regional groundwater level. Firstly, from the qualitative analysis angle, it was selected eight observation wells along the river channel. Through the comparison of the groundwater level before and after the same precipitation, this was the first qualitative understanding about how to affect the water level of water delivery. Secondly, by using grey correlation analysis, the factors affecting the groundwater level were quantified, and the grey correlation degree between the influencing factors and underground water level was obtained. Through the correlation degree, to quantify the impact of various factors. Meanwhile, the area affected by the water transfer from the South-to-North Water Transfer Project was defined. On the basis of quantitative analysis, by using Visual MODFLOW to establish the numerical model of groundwater in the study area, by the Kriging interpolation model to optimize accuracy, the model is validated through the measured datas of four water delivery, and the channel leakage in the previous water delivery period was evaluated. Finally, the model was employed to predict the groundwater level during the next five years. The main conclusions are as follows:(1)After the delivery, due to an increase in the influencing factor of groundwater, the correlation degree of precipitation and groundwater amplitude dropped to 0.69 from 0.8, but the correlation degree of delivery and groundwater amplitude reached to 0.71, The delivery became the main factor. The longer the water delivery time, the larger rdelivery time in the 4 major observationg wells. Because of far away from the river, the rdelivery time was less than major observation wells in the 4 contrasting wells. Through the analysis of the middle distance and rdelivery time, the delivery affected the groundwater level on both sides of 6.6km regions in Liang Ji canal. The correlation degree of delivery and underground water level was from 0.6 to 0.8. Outside 6.6km, the underground water level was weak affected by the water delivery.(2)According to this region, the optimization scheme added 7 virtual observation wells by using Kriging interpolation model. After optimization, the standard deviation was roughly between 0.5 and 0.8, which was significantly improved before optimization. The groundwater numerical model established by the optimized observation network was superior to the the original. This shows that the Kriging interpolation model is helpful to improve the calculation precision, and it can provide more accurate calculation results, support for the management of groundwater resources with more reliable datas.(3) By using the established model, through water balance calculation, channel leakage was analyzed.Before the flood season, the river leakage was larger, which was about 300 to 400 thousand m3/d; After the flood season, the river leakage was smaller, which was 15 thousand m3/d. The leakage was mainly focused on Denglou to Changgou.(4) Using the validated model, we predict the change of regional groundwater in the next 5 years. By 2020, the trend of groundwater flow of Liangji canal is small, the overall flow is from the northeast and east to the southwest. But the groundwater hydraulic gradient becomes slow and the water level raises. The rising of water level is mainly concentrated on Denglou to Changgou near Changgou pumping station.the maximum lifting height is up to 6.0m. The lifting height of water level is from 0.5 to 1.5m in Baliwan to Denglou pumping station, and it is from 1.5 to 2.0m in the south of Changgou to Hukou. It is predicted that the groundwater level fluctuation is still first falling then rising in 2020, and the lowest water level still appears in July or so, which is consistent with 2015. But the fluctuation in 2020 is significantly more stable than that in 2015, and the amplitude is decreased obviously. The variation of groundwater level is from 1.5 to 2.0m in 2015, and from 0.5 to 1.0m in 2020.In this study, the influence on shallow groundwater in Liang-Ji canal zone due to water transfer projection was analyzed. The quantity of recharge, the recharge area and changing trend in groundwater after water transmission are clear. There will be of great significance to the rational development and utilization of groundwater resources in the area influenced by water transmission. |
PDF Full Text Request