Presenter
Dr. Feng SUN, Information Center (Hydrology and Water Resources Monitoring and Forecasting Center)
Co-author(s)
Dr. Hongjian LU, Information Center (Hydrology and Water Resources Monitoring and Forecasting Center)
Mr. Lin MEI, Information Center (Hydrology and Water Resources Monitoring and Forecasting Center)
Sub-theme
4. Supporting Aquatic Ecosystem Health and Functions
Topic
4-7. Groundwater and ecosystem
Body
The North China Plain (NCP) aquifer system underlies areas supporting about 110 million population in metropolitan cities of Beijing, Tianjin and Hebei province, which supplies water of 18.8 billion cubic meters per year as important local water source, accounting for 75% of that. Some NCP aquifers are over exploited due to agriculture, industrial and domestic water use, which has led to a series of eco-environmental problems, such as surface depressions, seawater intrusion, etc. In this study, the time series data such as groundwater table, hardness, total dissolved solid, pH, chloride, sulphate, ammonia and nitrate, etc., was analyzed with Mann-Kendall test and wavelet analysis method to characterize the trends and change patterns in the last 30 years of groundwater tables and chemical constituents in NCP aquifers. The controlling factors affecting the changes of groundwater tables and quality in those over-exploited aquifers were identified by the attribution analysis method. The relationship among the chemical constituents, groundwater tables, precipitation and groundwater exploitation or other human activities was analyzed by multiple variables regression. The results indicate that: (1) the most rapidly decreasing rate of groundwater table occurred between 2000 and 2014 in the last 30 years; (2) groundwater exploitation and precipitation recharge are the controlling factors affecting groundwater table change in the shallow aquifers of the NCP, and artificial recharge has an influence on groundwater table change too; (3) the groundwater tables in some monitoring wells of the study area have recovered slowly with the water diversion from south to north since 2014 and the action of comprehensive treatment of over-exploited areas initiated by Ministry of Water Resources of P. R. China; (4) the groundwater quality has an inverse trend of groundwater table; (5) the concentrations of inorganic constituents could be affected by natural processes as well as by human activities and the usage of chemical fertilizer and the distributed discharge of domestic sewage are major contributions to ammonia and nitrate concentrations growth in some aquifers.