Groundwater-surface Water Interaction In Songhuajiang-Naoli River Basin Of Sanjiang Plain

The Sanjiang Plain is one of China's largest grain production and inland freshwater wetland region,and plays an important role in ensuring food security in China and protecting regional biodiversity,ecosystem landscape diversity,water conservation,water purification and regulating atmospheric precipitation.Agricultural water accounts for 83.3% of the total water consumption in Sanjiang Plain which mainly from exploiting of groundwater,resulting in a significant drop in groundwater level in some regions,the shortage and reduced function of wetland water resources and regional water cycle and water resources change.The research on the transformation relationship between surface water and groundwater in this region is relatively scarce,which restricts the rational development and sustainable utilization and protection of local water resources.Therefore,a systematic study of the interaction between groundwater and surface water in the Songhuajiang River and Naoli River basin of Sanjiang Plain is of great theoretical and practical significance for the scientific evaluation of the water resources quantity and the potential for development and utilization of the Sanjiang Plain.Based on the analysis of the geological and hydrogeological conditions of Songhuajiang River and Naoli River basin in the Sanjiang Plain,this paper chooses typical sections and reaches,uses hydrochemistry and isotope theory,combines field hydrogeology survey,field sampling and indoor testing to investigate the transformation relationship between surface water and groundwater in the Sanjiang Plain.the conclusions are as following.1.The hydrochemical types of surface water in the study area are mainly as HCO3-Na·Ca and HCO3-Ca·Na,which are mainly influenced by rock dissolution,but not evaporation and the primary chemistry of precipitation.The groundwater types are mostly as Cl,SO4 and HCO3 composite types,and groundwater is mainly affected by water rock interactions and human activities.Anions and cations mainly come from aluminosilicate,halite,calcite and dolomite.other sources are from pollution.2.Most of the groundwater and surface water samples in the study area are distributed near the local meteoric water line,indicating that precipitation is the main source of river water and groundwater in the Songhuajiang River Basin.3.Hydration method,isotope method and hydrodynamic method verify each other,and the results of groundwater and surface water transformation are consistent.4.Groundwater and surface water have the same transformation relationship in the whole Songhuajiang River in the study area during the flood season and groundwater recharged by surface water;Groundwater and surface water are recharged by surface water in most areas in the level water period,while groundwater is recharged by surface water only on the right bank of downstream Songhua River;groundwater and surface water are changed greatly in the low water period,and the transformation relations between upper,middle,lower and left banks are different.5.Groundwater is recharged by rivers and lakes in the Naoli River Basin during the flood season,while groundwater is recharged by lakes in the Naoli River Basin during the flood season;groundwater is recharged by surface water in the Xiao Naoli River Basin during the plain season;surface water in the Waiqixing River receives groundwater recharge;surface water is recharged by surface water in the middle and lower reaches of the Naoli River,and surface water is recharged by groundwater in the south of Surface water recharges groundwater on the right bank of upstream and downstream parts of Naoli River during the water period,while groundwater recharges surface water on the middle and downstream parts.Surface water in the third ring of Naoli River receives the recharge of surrounding groundwater in all periods.