Remote Sensing Monitoring And Driving Factor Analysis Of Water Storage In High Intensity Coal Mining Areas

The cities of yan'an and Yulin(hereinafter referred to as northern shaanxi),ordos and shanxi are extremely short of water resources.But at the same time,this area is rich in coal resources.The coal seams are buried shallow,thick and have many layers.It is a typical high-intensity coal mining area in China,coal mining causes serious damage to local ecology and water resources environment.At the same time,agricultural planting area in the study area is large and agricultural irrigation water consumption accounts for a large proportion of total water consumption.Coal mining,agricultural irrigation water consumption and other multiple effects,resulting in the scarcity of water resources more strained.Therefore,how to quantitatively study the changes of water resources in high-intensity coal mining areas and determine the hydrologic variables with significant changes and their main driving factors are of great significance to the rational utilization of water resources in this area.Traditional monitoring methods for water resources in mining areas are to monitor groundwater level and surface water changes based on a single monitoring well,or to extract Soil Moisture(SM)or river and lake area by using remote sensing images or to simulate regional water resource changes based on distributed hydrological models.However,the spatial distribution of monitoring wells is not uniform and is easily affected by human observation error and surrounding pumping.Remote sensing image is easily restricted by its own quality and can only monitor the change of shallow surface water resources.Most of the distributed hydrological models are set for a specific region and their applicability is limited.Moreover,the above traditional methods cannot quantitatively monitor regional water resources changes from the perspective of water reserves.At the same time,the traditional research on the relationship between the change of water resources and driving factors is mostly carried out from the qualitative perspective.Therefore,in view of the shortcomings of traditional water resources monitoring and driving factor analysis methods in high-intensity coal mining areas,it is urgent to select a technical method that is not affected by the surrounding environment and climate,has a uniform spatial distribution,and is comprehensive and universal.At the same time,a driving force analysis model that can determine the main driving factors of regional water resource change qualitatively and quantitatively is constructed to provide data support for the rational planning and distribution of water resources in the future.Gravity Recovery and Climate Experiment(GRACE)Satellite has the advantages of uniform observation scales and uniform distribution.This technology can effectively make up for the shortcomings of remote sensing data that can only observe shallow surface soil water,the uneven spatial distribution of hydrological stations and weather stations,and the poor universality of numerical models,and can quantitatively retrieve regional water reserves,which provides a new approach for the study of regional water resource changes.Based on the comparison of traditional remote sensing image extraction methods for surface water area,combing with the balance equation of water reserves in the land region,the quantitative estimation model of remote sensing for WGHM-GRACE hydrological variables was constructed.The Surface Water Storage Anomalies(SWSA)and Terrestrial Water Storage Anomalies(TWSA)after the deduction of the quality change caused by coal mining were extracted,and the Groundwater Storage Anomalies(GWSA)after the deduction of the quality change caused by coal mining was quantitatively calculated and verified by the measured groundwater level data.The temporal and spatial variation trend of each hydrologic variable is analyzed and compared to obtain the hydrologic variable with significant variation.By establishing the driving force analysis model of grey slope relational degree-partial least square regression method,the relationship between hydrological variables with significant changes and driving factors was qualitatively analyzed,and determine the potential driving factors.On this basis,the main driving factors and influence weights of hydrologic variables with significant regional changes are determined quantitatively.The results show that:(1)Based on the established quantitative remote sensing estimation model of WGHM-GRACE hydrological variables,it was calculated that the Surface Water Storage(SWS)in northern shaanxi,ordos and shanxi increased slowly at the rates of 0.03cm/a and 0.01cm/a,while the TWS decreased rapidly at-0.63cm/a and-1.10cm/a,respectively.The variation trend of TWS was much larger than that of SWS.(2)By using GRACE satellite and WGHM hydrological model,the GWS in northern shaanxi,ordos and shanxi were calculated,which were in good agreement with the measured annual groundwater level,and the correlation reached 0.72 and 0.88,respectively.It was calculated that the GWS in the two regions decreased at-0.65cm/a and-1.16cm/a,respectively.The results of the comparison of spatial and temporal variation trends of SWS,TWS and GWS show that the spatial distribution and variation trends of GWS and TWS in the same region are in good consistency.The loss of GWS is slightly larger than that of TWS,while SWS shows a state of surplus,which proves that GWS change is dominant in TWS change and is the most significant hydrological variable.(3)Through the driving force analysis model of grey slope relational degree-partial least square regression method,the comprehensive analysis shows that from 2003 to 2014,the main driving factor of GWS change in northern shaanxi and ordos is coal mining water consumption.The main driving factors of GWS change in Shanxi are water consumption for coal mining and agricultural irrigation,and the corresponding influence weight of the two driving factors is 50.00%.From the analysis results of the main driving factors,it can be seen that coal mining water consumption has a significant impact on the change of groundwater reserves of the two regions.