Using time series analysis to assess tidal effect on coastal groundwater level in Southern Laizhou Bay, China  

作　　者：She-ming Chen Hong-wei Liu Fu-tian Liu Jin-jie Miao Xu Guo Zhou Zhang Wan-jun Jiang 

机构地区：[1]Tianjin Center of China Geological Survey,Ministry of Natural Resources,Tianjin 300170,China

出　　处：《Journal of Groundwater Science and Engineering》2022年第3期292-301,共10页地下水科学与工程（英文版）

基　　金：funded by the“Investigation and Evaluation of Geologic Environment for Laizhou Bay”of the China Geological Survey project(12120113003800);financially supported by National Natural Science Foundation of China(No.42102298);the program of China Geology Survey(No.DD20221759).

摘　　要：Sea water intrusion is an environmental problem cause by the irrational exploitation of coastal groundwater resources and has attracted the attention of many coastal countries.In this study,we used time series monitoring data of groundwater levels and tidal waves to analyze the influence of tide flow on groundwater dynamics in the southern Laizhou Bay.The auto-correlation and cross-correlation coefficients between groundwater level and tidal wave level were calculated specifically to measure the boundary conditions along the coastline.In addition,spectrum analysis was employed to assess the periodicity and hysteresis of various tide and groundwater level fluctuations.The results of time series analysis show that groundwater level fluctuation is noticeably influenced by tides,but the influence is limited to a certain distance and cannot reach the saltwater-freshwater interface in the southern Laizhou Bay.There are three main periodic components of groundwater level in tidal effect range(i.e.23.804 h,12.500 h and 12.046 h),the pattern of which is the same as the tides.The affected groundwater level fluctuations lag behind the tides.The dynamic analysis of groundwater indicates that the coastal aquifer has a hydraulic connection with seawater but not in a direct way.Owing to the existence of the groundwater mound between the salty groundwater(brine)and fresh groundwater,the maximum influencing distance of the tide on the groundwater is 8.85 km.Considering that the fresh-saline groundwater interface is about 30 km away from the coastline,modern seawater has a limited contribution to sea-salt water intrusion in Laizhou Bay.The results of this study are expected to provide a reference for the study on sea water intrusion.

关 键 词：GROUNDWATER Time series analysis CORRELATION Spectral analysis Sea-salt water intrusion 

分 类 号：P641.2[天文地球—地质矿产勘探] P731.2[天文地球—地质学]