Study On Groundwater Evolution Under Changing Enviroment In Zhongmou County

Groundwater carries extremely important functions of resources,ecology and geological environment.It plays an important role in ensuring the economic and social development and the health of the ecosystem.With the increase of global climate change and human activities,groundwater systems suffer from a series of ecological and geological problems.The relationship between groundwater system and climate and human activities and groundwater circulation process are much more complex than surface water.At present,the research on the impact of changing environment on groundwater is still in its infancy.The study of the impact of changes in the environment,especially the impact of climate change,from surface water to groundwater,and the assessment of the impact of changes in climate and human activity intensity on groundwater systems will be conducive to the safe use of groundwater resources in changing environments.The paper relies on the research fund project of the Ministry of Water Resources for the public welfare industry and takes Zhongmu County as a typical research area to carry out the research on regional groundwater evolution in a changing environment.The thesis mainly includes three parts: the trend of groundwater dynamics in Zhongmu County is analyzed by trend,continuity,abrupt and cyclical methods;the groundwater circulation law is studied by numerical simulation;the groundwater response under changing environment is discussed.The main research results are as follows:(1)According to the groundwater depth data of 17 groundwater observation wells in the study area from 1990 to 2013,the trend of groundwater dynamics in the study area was analyzed by linear trend and Mann-Kendall trend method;the Hurst index was calculated based on R/S method.The capacity dimension D0 was used to analyze the continuity of the dynamic change of groundwater.Mann-Kendall mutation analysis method and wavelet analysis method were used to analyze the variability and periodicity of groundwater dynamic change.At the same time,the above methods were used to analyze the characteristics of meteorological elements in the study area.The results showed that the groundwater depth in the study area showed a downward trend,and this trend will continue.The year of abrupt changes in groundwater depth was 1992 and 2013,the first main period of groundwater change was 22 years,and the second main period was 9 years;Variations in the meteorological factors such as evaporation have a certain correlation with the trend,sustainability,and periodicity of groundwater depth.(2)By collecting data such as formation lithology,groundwater development and utilization,and groundwater level in the study area,a conceptual model for hydrogeology in the study area was established;using the MODFLOW module in the GMS software,a numerical simulation model for groundwater flow in the study area was constructed.The results show that the general trend of the groundwater flow field is from the southwest to the northeast.After the model identification and verification,the o verall flow direction of the groundwater simulation flow field and the measured flow field is consistent,and the distribution of the water level lines is relatively close.The simulated and measured values of the observation hole water level The fitting is more consistent,and the groundwater numerical simulation model can better reflect the hydrogeological conditions and flow conditions.(3)Estimated global climate model based on the three emission scenarios of Rcp2.6,Rcp4.5,and Rcp8.5 based on the Had GEM2-ES model,with 2015 as the current year,based on the climate-human activity-groundwater according to the study area The relationship between the systems,the development of three scenarios,current scenarios,climate change scenarios,and climate change-autonomous changes in human activities,and the study of groundwater changes under different scenarios.The results show that the current situation,regardless of climate change and changes in human activities,is that the average annual groundwater level has decreased by 0.04 m from 2016 to 2050.In recent years,the groundwater level in the study area has decreased by an average of 0.06 m.The simulation results are credible;the climate change scenario considers climate change.The impact of induced human activities on shallow groundwater levels is divided into 8 scenarios,of which the average 2020 and 2050 climate scenarios indirectly affect the program groundwater flow field and the baseline scenario flow field are basically the same;climate c hange-autonomous changes in human activities Scenarios that comprehensively consider the impact of climate change,climate change-induced human activities,and autonomous human activities on shallow groundwater levels,with shallow groundwater levels falling under average climatic conditions,and the set of autonomous human activity change measures insufficient to respond to groundwater downward trend.