Research on Evolution of Groundwater Circulation Environment in Sanjiang Plain
|Course||Hydrology and Water Resources|
|Keywords||Sanjiang Plain Groundwater circulation Transformation of the relationship of the surface water and groundwater Numerical Simulation of Groundwater|
Sanjiang Plain is located in the northeastern region of China, a low-lying fertile soil, Heilongjiang and Ussuri River constitutes the plains of northern and eastern borders, the Songhua River from the plains roll on. Experienced from the early days to now more than 50 years of agricultural development in the Sanjiang Plain has become the first \However, excessive land reclamation plains ecological environment has changed dramatically, water tables are falling, the wetland area is reduced by more than 80%, facing a great threat to species diversity. Therefore, in the future development strategy, how to achieve the rational exploitation of groundwater resources and the effective use of, in order to achieve the coordinated development of ecological and environmental protection and agricultural production has become important problems of the area to be solved. This article, based on a large collection of the study area, hydrological, meteorological, geological and hydrogeological data, systems analysis study area aquifer and groundwater occurrence form of complement diameter discharge conditions and groundwater dynamics, focusing on the local groundwater and surface between water supply and drainage and groundwater circulation environment evolution, and the establishment of a numerical model of groundwater flow plain area groundwater level and cyclic evolution trend forecast analysis. The Sanjiang Plain climate of the continental monsoon climate, rain and heat in the same quarter. The major exploitation of the aquifer the Quaternary unconsolidated rock porosity aquifer Quaternary sand, gravel, stone aqueous medium. Wandashan for the watershed study area can be divided into the the small Sanjiang low plains and Muling - Xingkai Plain two groundwater subsystem. Affected by the topography, the flow direction of groundwater flow from southwest to northeast. Aquifer recharge sources of meteoric recharge, as well as mountain bedrock fissure water lateral flow recharge, river recharge from lateral leakage of supply and farm irrigation; more groundwater discharge pathway, mainly include artificial mining, diving evaporation along the Strip river excretion and lateral outflow. Dynamic type of the groundwater, including the infiltration of precipitation - evaporation, hydrology and mining type. Close hydraulic connection between the groundwater and rivers, can be seen by the simulation results of the model established by GMS, most of the rivers in the region and groundwater is a complementary relationship between the dry season the excretion of groundwater to the river, wet period the river recharge groundwater, due to the increase in the amount of riverside mining, leading to falling water tables, the general trend of the year with flat water surface water recharge groundwater, the total amount of up to 277,392,000 m3. Agricultural development in the Sanjiang Plain Groundwater cycling conditions from the mid-20th century, the major changes occurred. The groundwater cycle alternating speed from slow to fast, groundwater recharge and discharge diversification, labor exploitation is becoming the major excretion pathway of some groundwater recharge and excretion increased by more than 70%. Groundwater recharge and discharge from the initial equilibrium, evolution is a long time in over-exploited, water tables are falling, and in some areas to form a cone of depression. The the surface ecological situation changed dramatically, wetlands area disappeared for more than 80%, increase in cultivated area about 38.55x105hm2 of climate and environment on the plains drought trend. The plains land use, groundwater conditions and temperature changes in precipitation and groundwater level changes in the correlation analysis, show that the amount of groundwater exploitation has increased year by year is the main cause of the evolution of the groundwater circulation environment, a large number of cultivated area increased the lead to surface conditions changes in temperature and precipitation changes, as well as surface drainage impact exacerbated this evolutionary trend. Currently, the country has a certain emphasis on ecological and environmental protection work in the plains. The numerical model of groundwater flow simulation results show that the future conditions of the groundwater exploitation decreasing the Sanjiang Plain groundwater storage can be certain recovery, recovery of up to 2030 a total of 3.029 billion m3. Groundwater levels declining trend will be curbed, there will be some rebound in some areas. In future development planning, should control the paddy fields to increase speed, to take effective water-saving irrigation measures, the development of water resources at the same time, you should take the joint exploitation of groundwater and surface water, unified scheduling to take full account of the ecological water demand.