Research On Groundwater Circulation And Transform Relationship With River Water Of Naoli River Basin

The Naoli River Basin is located in the hinterland of the Sanjiang plain in the east of Heilongjiang province,because of tectonic movement and the frequent diversion of the river,basin deposited thick quaternary lacustrine loose sediments.The terrain of Naoli River is flat and open,and the aquifer has wide distribution area,large volume,which is beneficial to the formation and storage of groundwater.Due to the unique types of soil and groundwater resources,the study area has become an important commodity grain base in China.With the exploitation of groundwater in some areas of the basin in successive years is greater than the allowable withdrawal of groundwater.With the continuous decline of groundwater level,the dynamic characteristics of regional groundwater,the transformation of groundwater and river water and groundwater circulation patterns have changed.The groundwater dynamic type of Naoli River Basin is divided into four categories in this paper,in the plain area,the most widely distributed dynamic type is precipitation infiltration evaporation.The tape of artificial exploitation is mainly distributed in well irrigation area where the paddy field is contiguous distribution in the northern and eastern plains of the basin.and with the continued increase in the amount of artificial exploitation,the distribution range of artificial exploitation type will gradually move to the west,the area gradually expanded.Hydrological groundwater regime is mainly distributed in the valley area of the lower reaches of the Naoli River and Qixing River in which the river water perennial supply of groundwater.With the uncontrolled exploitation of groundwater,this distribution range will be expanded.The recharge,runoff and discharge conditions of groundwater have changed greatly over time in this basin.In the northern and eastern plain area,the coefficient of precipitation infiltration with time showed decreased after increasing trend,the precipitation infiltration of the central plains area over time showed a decreased recharge coefficient,and has been maintained at high levels.The way of groundwater discharge has changed greatly with the passage of time.In the northern and eastern parts of the basin,the way of groundwater discharge is single,artificial exploitation of groundwater has gradually replaced evaporation as the most important form of drainage in this area.In recent years,with the increase of paddy field area,groundwater exploitation is high,the local underground water level continued to decline,led to the changes of flow field characteristics of groundwater,groundwater circulation mode and the transformation of groundwater and river water also has changed.The groundwater circulation pattern has changed from a single model to a variety of circulation patterns.The transformation model of river water and groundwater is transformed from a single pattern of different seasons to the transformation mode of perennial recharge or discharge of groundwater.For the calculation of the conversion between the river water and the groundwater,this paper applies the Darcy's law and the unsteady flow formula to calculate the conversion of the river and groundwater in plain area.The year 2014 as the base year,the amount of river water translate to groundwater is 6045.19×104m3,the amount of water supplied by groundwater is 2189.78×104m3.The amount of groundwater supplied by the river has been increasing in recent years.The basic flow cutting method is used to calculate the amount of water supply in mountainous area.According to the calculation results,it is known that the amount of water supplied by groundwater in mountain area is related to the amount of groundwater recharge of precipitation.In this paper,the amount of groundwater resources are calculated and discussed,according to the calculation results,irrigation return recharge accounted for the proportion of the amount of recharge of groundwater resources in the basin increased gradually.The amount of groundwater resources increases first and then decreases with the passage of time.The amount of water resources in the study area changes from 12.5×108m3~16.5×108m3 in recent years,and the average value of the modulus of groundwater resources in the valley can reach 11.5×104m3/km2·a.The groundwater resource modulus of the river terrace is similar to that of platform,and the mean value is 6.5×104m3/km2·a.The variation of groundwater resources follow the variation of atmospheric precipitation,and the amount was positively correlated with precipitation,but the proportion of groundwater specific in recent years is relatively stable.