This paper focuses on the dynamic variation of groundwater level in Lhasacity. According to the data, the obvious characteristic of the groundwater level of the city is thatit is changing seasonally. Lhasa is divided ...This paper focuses on the dynamic variation of groundwater level in Lhasacity. According to the data, the obvious characteristic of the groundwater level of the city is thatit is changing seasonally. Lhasa is divided into three districts according to hydrogeologicalconditions: the alluvial plain of the Lhasa-river, the alluvial plain of the Doilung-river, and thealluvial fan of inter mountain, which presents a downward trend, a slight upward trend and basicallystabilizing trend over the years individually. The analysis indicates that meteorological andhydrological factors lead to the obvious dynamic change of the groundwater level. However, more andmore human activities and over-exploitation of the groundwater cause the downward trend inthegroundwater level.展开更多
An explicit model management framework is introduced for predictive Groundwater Levels(GWL),particularly suitable to Observation Wells(OWs)with sparse and possibly heterogeneous data.The framework implements Multiple ...An explicit model management framework is introduced for predictive Groundwater Levels(GWL),particularly suitable to Observation Wells(OWs)with sparse and possibly heterogeneous data.The framework implements Multiple Models(MM)under the architecture of organising them at levels,as follows:(i)Level 0:treat heterogeneity in the data,e.g.Self-Organised Mapping(SOM)to classify the OWs;and decide on model structure,e.g.formulate a grey box model to predict GWLs.(ii)Level 1:construct MMs,e.g.two Fuzzy Logic(FL)and one Neurofuzzy(NF)models.(iii)Level 2:formulate strategies to combine the MM at Level 1,for which the paper uses Artificial Neural Networks(Strategy 1)and simple averaging(Strategy 2).Whilst the above model management strategy is novel,a critical view is presented,according to which modelling practices are:Inclusive Multiple Modelling(IMM)practices contrasted with existing practices,branded by the paper as Exclusionary Multiple Modelling(EMM).Scientific thinking over IMMs is captured as a framework with four dimensions:Model Reuse(MR),Hierarchical Recursion(HR),Elastic Learning Environment(ELE)and Goal Orientation(GO)and these together make the acronym of RHEO.Therefore,IMM-RHEO is piloted in the aquifer of Tabriz Plain with sparse and possibly heterogeneous data.The results provide some evidence that(i)IMM at two levels improves on the accuracy of individual models;and(ii)model combinations in IMM practices bring‘model-learning’into fashion for learning with the goal to explain baseline conditions and impacts of subsequent management changes.展开更多
Groundwater is important for managing the water supply in agricultural countries like Bangladesh. Therefore, the ability to predict the changes of groundwater level is necessary for jointly planning the uses of ground...Groundwater is important for managing the water supply in agricultural countries like Bangladesh. Therefore, the ability to predict the changes of groundwater level is necessary for jointly planning the uses of groundwater resources. In this study, a new nonlinear autoregressive with exogenous inputs(NARX) network has been applied to simulate monthly groundwater levels in a well of Sylhet Sadar at a local scale. The Levenberg-Marquardt(LM) and Bayesian Regularization(BR) algorithms were used to train the NARX network, and the results were compared to determine the best architecture for predicting monthly groundwater levels over time. The comparison between LM and BR showed that NARX-BR has advantages over predicting monthly levels based on the Mean Squared Error(MSE), coefficient of determination(R^2), and Nash-Sutcliffe coefficient of efficiency(NSE). The results show that BR is the most accurate method for predicting groundwater levels with an error of ± 0.35 m. This method is applied to the management of irrigation water source, which provides important information for the prediction of local groundwater fluctuation at local level during a short period.展开更多
Groundwater resources provide most of the domestic water supply in rural Zimbabwe and support poverty reduction through irrigation facilities. Most agricultural and environmental plans need water table depth analysis ...Groundwater resources provide most of the domestic water supply in rural Zimbabwe and support poverty reduction through irrigation facilities. Most agricultural and environmental plans need water table depth analysis as an input in designing best management strategies. There are limited direct measurements of groundwater levels in Zimbabwe due to high costs and the limited human expertise. The study is aimed at coming up with a proof of concept that altitude of rivers as determined by an SRTM digital elevation model can be used to estimate the levels of groundwater in parts of Mutirikwi and Runde sub catchments of southern Zimbabwe. The study also maps the groundwater levels of the area as determined by river altitude from the digital elevation model. Firstly, the groundwater levels for nine boreholes are measured. Secondly, the altitude of a river bed nearest to each borehole site is extracted from a digital elevation model. Finally, the Spearman’s correlation coefficient is used to determine the nature and strength of the relationship between the two variables. Linear regression analysis was also used to obtain the predictive equation of the relationship and its coefficient of determination. After the relationship between groundwater and river altitude is established, 9 new random points of river altitude are generated across the study area interpolated using kriging interpolation to give the estimated altitude of river altitude. The altitude of groundwater is then determined by running the predictive equation Y = 0.8736 * X + 0.852 obtained from regression analysis. The depth to groundwater level of area is obtained by subtracting the determined groundwater altitude from the SRTM DEM. The results show strong positive and statistically significant (ρ = 0.000, α = 0.01) correlation coefficient of 0.971 between measured groundwater levels and altitude of rivers. The regression model shows a coefficient of determination (r2) of 0.975. The research therefore determines that altitude of rivers and use of geostatistics can produce physically plausible estimates of groundwater levels in the study area.展开更多
Climate change and increasing anthropogenic activities,such as over-exploitation of groundwater,are exerting unavoidable stress on groundwater resources.This study investigated the spatio-temporal variation of depth t...Climate change and increasing anthropogenic activities,such as over-exploitation of groundwater,are exerting unavoidable stress on groundwater resources.This study investigated the spatio-temporal variation of depth to groundwater level(DGWL)and the impacts of climatic(precipitation,maximum temperature,and minimum temperature)and anthropogenic(gross district product(GDP),population,and net irrigated area(NIA))variables on DGWL during 1994-2020.The study considered DGWL in 113 observation wells and piezometers located in arid western plains(Barmer and Jodhpur districts)and semi-arid eastern plains(Jaipur,Ajmer,Dausa,and Tonk districts)of Rajasthan State,India.Statistical methods were employed to examine the annual and seasonal patterns of DGWL,and the generalized additive model(GAM)was used to determine the impacts of climatic and anthropogenic variables on DGWL.During 1994-2020,except for Barmer District,where the mean annual DGWL was almost constant(around 26.50 m),all other districts exhibited increase in DGWL,with Ajmer District experiencing the most increase.The results also revealed that 36 observation wells and piezometers showed a statistically significant annual increasing trend in DGWL and 34 observation wells and piezometers exhibited a statistically significant decreasing trend in DGWL.Similarly,32 observation wells and piezometers showed an statistically significant increasing trend and 37 observation wells and piezometers showed a statistically significant decreasing trend in winter;33 observation wells and piezometers indicated a statistically significant increasing trend and 34 had a statistically significant decreasing trend in post-monsoon;35 observation wells and piezometers exhibited a statistically significant increasing trend and 32 observation wells and piezometers showed a statistically significant decreasing trend in pre-monsoon;and 36 observation wells and piezometers reflected a statistically significant increasing trend and 30 observation wells and piezometers reflected a statistically significant decreasing trend in monsoon.Interestingly,most of the observation wells and piezometers with increasing trends of DGWL were located in Dausa and Jaipur districts.Furthermore,the GAM analysis revealed that climatic variables,such as precipitation,significantly affected DGWL in Barmer District,and DGWL in all other districts was influenced by anthropogenic variables,including GDP,NIA,and population.As a result,stringent regulations should be implemented to curb excessive groundwater extraction,manage agricultural water demand,initiate proactive aquifer recharge programs,and strengthen sustainable management in these water-scarce regions.展开更多
Adequate regional groundwater assessment studies are essential for the correct groundwater management by policy/decision makers; increased use of groundwater resources and drought have led to concern about the future ...Adequate regional groundwater assessment studies are essential for the correct groundwater management by policy/decision makers; increased use of groundwater resources and drought have led to concern about the future availability of groundwater to meet domestic, agricultural, industrial, and environmental needs. Deep understanding of spatial and temporal water table dynamics together with transport processes is required. This paper gathers historical geological, hidrological and chemical information for quantitative and qualitative as well as spatial and temporal evolution of groundwater for Aguanaval and Chupaderos aquifers, both surrounding Calera aquifer in Mexico. Historical databases were employed to determine temporal trends of water levels and values were projected for years 2010, 2030 and 2050. Potential recharge sites were also identified through water level-topography correlation. The water quality analysis was completed by obtaining, through geostatistics, spatial distributions for bicarbonate, chloride, sulfate, total dissolved solids, temperature, and sodium, employing databases generated in recent sampling campaigns. This analysis provided additional elements to help understand the functioning of groundwater in studied aquifers. Finally, results were compared with permissible values established in the Mexican norm.展开更多
This paper, based on the analysis and calculation of the groundwater resources in an arid region from 1980 to 2001, put forward the concept of ecological groundwater level threshold for either salinity control or the ...This paper, based on the analysis and calculation of the groundwater resources in an arid region from 1980 to 2001, put forward the concept of ecological groundwater level threshold for either salinity control or the determination of ecological warning. The surveys suggest that soil moisture and soil salinity are the most important environmental factors in determining the distribution and changes in vegetation. The groundwater level threshold of ecological warning can be determined by using a network of groundwater depth observation sites that monitor the environmental moisture gradient as reflected by plant physiological characteristics. According to long-term field observations within the Ejin oases, the groundwater level threshold for salinity control varied between 0.5 m and 1.5 m, and the ecological warning threshold varied between 3.5 m and 4.0 m. The quantity of groundwater re- sources (renewable water resources, ecological water resources, and exploitable water resources) in arid areas can be calculated from regional groundwater level information, without localized hydrogeological data. The concept of groundwater level threshold of ecological warning was established according to water development and water re- sources supply, and available groundwater resources were calculated. The concept not only enriches and broadens the content of groundwater studies, but also helps in predicting the prospects for water resources development.展开更多
Sampling and testing are conducted on groundwater depth and vegetation coverage in the 670 km2 of the Sangong River Basin and semi-variance function analysis is made afterwards on the data obtained by the application ...Sampling and testing are conducted on groundwater depth and vegetation coverage in the 670 km2 of the Sangong River Basin and semi-variance function analysis is made afterwards on the data obtained by the application of geo-statistics. Results showed that the variance curve of the groundwater depth and vegetation coverage displays an exponential model. Analysis of sampling data in 2003 indicates that the groundwater depth and vegetation coverage change similarly in space in this area. The Sangong River Basin is composed of upper oasis, middle ecotone and lower sand dune. In oasis and ecotone, influenced by irrigation of the adjoining oasis, groundwater level has been raised and soil water content also increased compared with sand dune nearby, vegetation developed well. But in the lower reaches of the Sangong River Basin, because of descending of groundwater level, soil water content decreased and vegetation degenerated. From oasis to abandoned land and desert grassland, vegetation coverage and groundwater level changed greatly with significant difference respectively in spatial variation. Distinct but similar spatial variability exists among the groundwater depth and vegetation coverage in the study area, namely, the vegetation coverage decreasing (increasing) as the groundwater depth increases (decreases). This illustrates the great dependence of vegetation coverage on groundwater depth in arid regions and further implies that among the great number of factors affecting vegetation coverage in arid regions, groundwater depth turns out to be the most determinant one.展开更多
Groundwater of Luohe Formation is the main water source for industrial and agricultural and residential use in Binchang mining area,which is one of the key elements to water conservation coal mining.However,few studie...Groundwater of Luohe Formation is the main water source for industrial and agricultural and residential use in Binchang mining area,which is one of the key elements to water conservation coal mining.However,few studies are available to document the enrichment characteristics and influence of underground coal mining on groundwater for the Luohe Formation.This study evaluates the changes of groundwater levels and spring flow caused by mining activities to explore the influence mechanism of coal mining on groundwater by comparatively analysing existing mining data and survey data combined with a series of mapping methods.The results show that the aquifer of Luohe Formation are gradually thinning south-eastwards,disappeared at the mining boundary.In the vertical direction,the lithological structure is distinct,due to alternative sedimentation of meandering river facies and braided river facies.According to the yielding property,the aquifer is divided into three sections,namely,strong water-rich section,medium water-rich section,and weak water-rich section,which are located in northwest and central part,southwest,and the rest part of the mining area,respectively.Mining of Tingnan Coal Mine since 2004 has caused a 3.16 to 194.87 meters drop in groundwater level of Luohe Formation.Until 2015,70.10%of the mining area undergoes a groundwater level drop larger than 10.00 meters.Another influence of underground mining is that the total flow from 34 springs in 8 southern coal mines of the area has decreased by 286.48 L/s with a rate of decrease at 46.95%from 2007 to 2017.The areas that groundwater level falls or spring flow declines are manly located in the mine gob areas.Results also indicate that the ratio of the height of water conducted fracture zone to the mining height in Binchang mining area is between 16.85 and 27.92.This may increase ground water flow in vertical direction,causing a water level in the aquifer system to drop and ultimately decreasing the flow from the springs.The research results will provide data and theoretical support for the protection of groundwater resources and water conservation coal mining of Luohe Formation in Binchang mining area.展开更多
At present,investigation about the relationship between the change of groundwater level and vegetation mostly focuses on specific watersheds,i.e.limited in river catchment scale.Understanding the change of groundwater...At present,investigation about the relationship between the change of groundwater level and vegetation mostly focuses on specific watersheds,i.e.limited in river catchment scale.Understanding the change of groundwater level on vegetation in the basin or large scale,be urgently needed.To fill this gap,two typical arid areas in the west of China(Tarim Basin and Qaidam Basin)were chosen the a typical research area.The vegetation status was evaluated via normalization difference vegetation index(NDVI)from 2000 to 2016,sourced from MODN1F dataset.The data used to reflect climate change were download from CMDSC(http://data.cma.cn).Groundwater level data was collected from monitor wells.Then,the relationship of vegetation and climate change was established with univariate linear regression and correlation analysis approach.Results show that:Generally,NDVI value in the study area decreased before 2004 then increased in the research period.Severe degradation was observed in the center of the basin.The area with an NDVI value>0.5 decreased from 12%to 6%between 2000 and 2004.From 2004 to 2014,the vegetation in the study area was gradually restored.The whole coverage of Qaidam Basin was low.And the NDVI around East Taigener salt-lake degraded significantly,from 0.596 to 0.005,2014 and 2016,respectively.The fluctuation of groundwater level is the main reason for the change of surface vegetation coverage during the vegetation degradation in the basin.However,the average annual precipitation in the study area is low,which is not enough to have a significant impact on vegetation growth.The annual average precipitation showed an increase trend during the vegetation restoration in the basin,which alleviates the water shortage of vegetation growth in the region.Meanwhile,the dependence of surface vegetation on groundwater is obviously weakened with the correlation index is−0.248.The research results are of some significance to eco-environment protection in the arid area of western China.展开更多
Delingha is located in the northeast margin of Qaidam Basin.Bayin River alluvial proluvial fan is the main aquifer of Delingha,in which groundwater generally flows from north to south.The hydrochemistry results showed...Delingha is located in the northeast margin of Qaidam Basin.Bayin River alluvial proluvial fan is the main aquifer of Delingha,in which groundwater generally flows from north to south.The hydrochemistry results showed that two different hydrochemical evolution paths formed along southeast and southwest directions,respectively.Cl-Na type groundwater was formed in front of Gahai Lake,and SO_(4)·HCO_(3)-Na·Ca type groundwater was formed in front of Keluke Lake.The results of deuterium(D)and 18O revealed that the groundwater mainly originated from the continuous accumulation of precipitation during geological history under cold and humid climate conditions.In addition,results of ^(14)C indicated that the groundwater age was more than 1140 years,implying relatively poor renewal capability of regional groundwater.Moreover,our numerical modeling results showed that the regional groundwater level will continue to rise under the warm and humid climate conditions.展开更多
The purpose of this paper was to assess the impact of urbanization on the groundwater level(GWL)in aquifers of Binh Duong(BD)Province.The research method is to analyze the trend of GWL,the recharge capacity of surface...The purpose of this paper was to assess the impact of urbanization on the groundwater level(GWL)in aquifers of Binh Duong(BD)Province.The research method is to analyze the trend of GWL,the recharge capacity of surface over time and the relationship between them.The data of the GWL used in the study are the average values in the dry and rainy seasons of 35 observation wells from 2011 to 2018,which are in Pleistocene and Pliocene aquifers.The ability to recharge groundwater from the surface in this study was represented by the curve number(CN),a parameter used in hydrology for calculating direct runoff or infiltration from rainfall.The land use data to identify the CN was analyzed from the Landsat images.The results show that besides over-exploitation,the change of surface characteristic due to the urbanization development process is also the cause of the GWL decline.The analysis of seasonal GWL data shows that the increase in impervious surface area is the cause of GWL decline in the Pleistocene aquifer,which is more evident in the rainy season than in the dry season.The statistical results also show that in the rainy season and in shallow aquifers,a higher CN change can be found with the wells that had a remarkable GWL decline compared to the remaining wells.展开更多
The shallow groundwater in Shendong mining area was broken because of large-scale underground mining activities. Selecting 32201 working-face as research area, analyzed the change rule of groundwater level and aquifer...The shallow groundwater in Shendong mining area was broken because of large-scale underground mining activities. Selecting 32201 working-face as research area, analyzed the change rule of groundwater level and aquifer thickness under mining impact with a large number of water level observation data. Then, the impacts of groundwater level change on vegetation were analyzed by the relationship theory of arid area groundwater and vegetation. The results show that the aquifer structure and the water condition of supply flow and drainage are changed by the water proof mining. The groundwater level recovere only a little compared with the original groundwater level in two years. But the great change of groundwater level do not have notable influences on vegetation of this mining area, and further study indicates that there are certain conditions where groundwater level change impacted on vegetation. When the influence of groundwater level change was evaluated, the plant ecological water level, warning water level and spatial distribution character of original groundwater and mining-impacted groundwater-level change should be integrated.展开更多
According to groundwater level monitoring data of Shuping landslide in the Three Gorges Reservoir area, based on the response relationship between influential factors such as rainfall and reservoir level and the chang...According to groundwater level monitoring data of Shuping landslide in the Three Gorges Reservoir area, based on the response relationship between influential factors such as rainfall and reservoir level and the change of groundwater level, the influential factors of groundwater level were selected. Then the classification and regression tree(CART) model was constructed by the subset and used to predict the groundwater level. Through the verification, the predictive results of the test sample were consistent with the actually measured values, and the mean absolute error and relative error is 0.28 m and 1.15%respectively. To compare the support vector machine(SVM) model constructed using the same set of factors, the mean absolute error and relative error of predicted results is 1.53 m and 6.11% respectively. It is indicated that CART model has not only better fitting and generalization ability, but also strong advantages in the analysis of landslide groundwater dynamic characteristics and the screening of important variables. It is an effective method for prediction of ground water level in landslides.展开更多
The Beijing-Tianjin-Hebei Plain(BTHP)is the political,economic and cultural center of China,where groundwater is the main source of water supply to support social and economic development.Continuous overdraft of the r...The Beijing-Tianjin-Hebei Plain(BTHP)is the political,economic and cultural center of China,where groundwater is the main source of water supply to support social and economic development.Continuous overdraft of the resources has caused a persistent decline of groundwater level and formed a huge cone of depression at a regional scale.This paper addresses current groundwater situation over the BTHP area.The paper also delineates the groundwater flow field,using groundwater level data,in order to provide an effective method for the restoration of groundwater level and associated water resources management.Based on the analysis of multiple factors,such as groundwater level,soil salinization,ground subsidence,groundwater recharge and storage,urban underground space security,formation of fractures,and seawater intrusion,the threshold for groundwater level restoration is defined,and some measures for groundwater over-exploitation management are accordingly proposed.The study shows that:(i)Since the 1980s to 2020,shallow groundwater level in the western part of the BTHP area has dropped by 25 m to 60m,while the cumulative decline of deep groundwater in the central and eastern regions is in the range of 40–80 m;(ii)The water table of the shallow groundwater within the depression zone over the Western Piedmont Plain should be controlled in the range of 15–30 m below ground level(mbgl),while the depth of groundwater level in large and medium-sized urban areas should be controlled within 20–30 mbgl.The groundwater level in the resource preservation area should be controlled within 10–15 mbgl,and the groundwater level in the area with identified soil salinization in the central and eastern plain should be controlled within 3–10 mbgl.However,for the deep groundwater in the central and eastern plainwater,the main focus of the resources management is to control the land subsidence.The water level in the severe land subsidence area should be controlled within 45–60 mbgl,and in the general subsidence area should be controlled within 30–45 mbgl;(iii)Based on the water level recovery threshold and proposed groundwater overdraft management program,if the balance of abstraction and recharge is reached in 2025,the shallow groundwater abstraction needs to be gradually reduced by about 2×10^(8) m^(3).Meanwhile,the ecological water replenishment of rivers through the South-to-North Water Transfer Project should be increased to 28.58×10^(8) m^(3)/a,and the deep groundwater abstraction needs to be gradually reduced by 2.24×10^(8) m^(3).To reach the target of shallow groundwater level in 2040,surface water replacement is recommended with a rate of 25.77×10^(8) m^(3)/a and the ecological water replenishment of rivers in the South-to-North Water Diversion Project should reach 33.51×10^(8) m^(3)/a.For deep groundwater recovery,it is recommended to replace the deep freshwater extraction with the utilization of shallow salt water by 2.82×10^(8) m^(3),in addition to the amount of 7.86×10^(8) m^(3) by water diversion.The results are of great significance to the remediation of groundwater over-exploitation,the regulation of water resources development and utilization,and ecological protection in Beijing-Tianjin-Hebei plain.展开更多
As the traditional non-linear systems generally based on gradient descent optimization method have some shortage in the field of groundwater level prediction, the paper, according to structure, algorithm and shortcomi...As the traditional non-linear systems generally based on gradient descent optimization method have some shortage in the field of groundwater level prediction, the paper, according to structure, algorithm and shortcoming of the conventional radial basis function neural network (RBF NN), presented a new improved genetic algorithm (GA): hybrid hierarchy genetic algorithm (HHGA). In training RBF NN, the algorithm can automatically determine the structure and parameters of RBF based on the given sample data. Compared with the traditional groundwater level prediction model based on back propagation (BP) or RBF NN, the new prediction model based on HHGA and RBF NN can greatly increase the convergence speed and precision.展开更多
Abandoned mines are of high potential risk as they could be a large underground storage of pollutants(heavy metals and organic wastes, etc.). Various physical, chemical and biological reactions would take place when g...Abandoned mines are of high potential risk as they could be a large underground storage of pollutants(heavy metals and organic wastes, etc.). Various physical, chemical and biological reactions would take place when groundwater flows into underground spaces, which makes abandoned mine a huge potential hazard to groundwater environment. The recovery of groundwater level is one of the key elements controlling the reactions and causing such hazards. This paper simulated groundwater level recovery processes in the abandoned mines, Fengfeng coalfield by using the computer program FEFLOW. The paper integrated the pipe flow model, "three zones" model and groundwater inrush(discharge) model in the simulation of groundwater in the complex laneway-aquifer system. Groundwater flow in the laneway systems was considered pipe flow and described in Bernoulli equation. The water-bearing medium(coal seam roof) overlying the laneway systems was divided into "three zones" composed of the caving zone, fissure zone and bending zone based on the disruption degrees of previous mining. Groundwater in the Ordovician limestone aquifer(bottom of coal seam) flowing into laneway systems was considered a major inrush/recharge source, and its flow rate was calculated by an inrush(discharge) model which was newly developed in this study and incorporated into FEFLOW. The results showed that it would take approximately 95 days for groundwater in abandoned mines to recover to regional groundwater level elevation, and the total amount of water filling up would be about 1.41195×10~7 m^3, which is consistent with the actual data. The study could be of theoretical and practical significance to mitigate abandoned mines' hazards and improve mine groundwater utilization.展开更多
Stochastic modelling of hydrological time series with insufficient length and data gaps is a serious challenge since these problems significantly affect the reliability of statistical models predicting and forecasting...Stochastic modelling of hydrological time series with insufficient length and data gaps is a serious challenge since these problems significantly affect the reliability of statistical models predicting and forecasting skills.In this paper,we proposed a method for searching the seasonal autoregressive integrated moving average(SARIMA)model parameters to predict the behavior of groundwater time series affected by the issues mentioned.Based on the analysis of statistical indices,8 stations among 44 available within the Campania region(Italy)have been selected as the highest quality measurements.Different SARIMA models,with different autoregressive,moving average and differentiation orders had been used.By reviewing the criteria used to determine the consistency and goodness-of-fit of the model,it is revealed that the model with specific combination of parameters,SARIMA(0,1,3)(0,1,2)_(12),has a high R^(2) value,larger than 92%,for each of the 8 selected stations.The same model has also good performances for what concern the forecasting skills,with an average NSE of about 96%.Therefore,this study has the potential to provide a new horizon for the simulation and reconstruction of groundwater time series within the investigated area.展开更多
Many factors can cause changes of groundwater level,such as the development process of an earthquake,rainfall,solid earth tides etc.Among these we are interested in information regarding earthquake development process...Many factors can cause changes of groundwater level,such as the development process of an earthquake,rainfall,solid earth tides etc.Among these we are interested in information regarding earthquake development processes.Eliminating the influence of various disturbance factors is an effective way to obtain seismic development process information contained in the groundwater level.This paper provides two different ways to remove the rainfall effect,and compares the two methods by means of correlation analysis.Furthermore,based on these a logistic regression model is established to describe the seismicity level.展开更多
The variations in both precipitation and temperature have far-reaching effects on agricultural activities and the accessibility of water resources. These climatic parameters are pivotal in determining the availability...The variations in both precipitation and temperature have far-reaching effects on agricultural activities and the accessibility of water resources. These climatic parameters are pivotal in determining the availability of both groundwater and surface water for agricultural use. The aim of this study was to evaluate the variations in climate parameters, focusing on precipitation and temperature, alongside changes in cultivated land area and crop yields in the Tadla area (Béni Mellal Khénifra region, Morocco);additionally, our research looks at the changes in water inflow into two dams and four aquifers. Trends were assessed over the period of 2010-2020 using the standardized precipitation index (SPI) method, as well as the parametric regression method and nonparametric Mann-Kendall and Sen’s slope test. This analysis can be a preliminary step in demonstrating the effects of climate variability on water resource availability and its adverse impacts on agriculture in the region. The results showed a decreasing trend for some yield crops despite the increase in the cultivated area. The results of the groundwater levels and inflow dams showed a significant upward evolution. The analysis of the obtained SPI values and temperatures has revealed a notable and consistent upward trendencies. This upward trajectory indicates that both the SPI values, which reflect precipitation patterns and the temperatures, have been on the rise over the examined period. These results prompt reflection on the effects of climate variability on water resources in the region and economic activities, particularly agriculture.展开更多
文摘This paper focuses on the dynamic variation of groundwater level in Lhasacity. According to the data, the obvious characteristic of the groundwater level of the city is thatit is changing seasonally. Lhasa is divided into three districts according to hydrogeologicalconditions: the alluvial plain of the Lhasa-river, the alluvial plain of the Doilung-river, and thealluvial fan of inter mountain, which presents a downward trend, a slight upward trend and basicallystabilizing trend over the years individually. The analysis indicates that meteorological andhydrological factors lead to the obvious dynamic change of the groundwater level. However, more andmore human activities and over-exploitation of the groundwater cause the downward trend inthegroundwater level.
基金the University of Tabriz through a Grant scheme No.808.
文摘An explicit model management framework is introduced for predictive Groundwater Levels(GWL),particularly suitable to Observation Wells(OWs)with sparse and possibly heterogeneous data.The framework implements Multiple Models(MM)under the architecture of organising them at levels,as follows:(i)Level 0:treat heterogeneity in the data,e.g.Self-Organised Mapping(SOM)to classify the OWs;and decide on model structure,e.g.formulate a grey box model to predict GWLs.(ii)Level 1:construct MMs,e.g.two Fuzzy Logic(FL)and one Neurofuzzy(NF)models.(iii)Level 2:formulate strategies to combine the MM at Level 1,for which the paper uses Artificial Neural Networks(Strategy 1)and simple averaging(Strategy 2).Whilst the above model management strategy is novel,a critical view is presented,according to which modelling practices are:Inclusive Multiple Modelling(IMM)practices contrasted with existing practices,branded by the paper as Exclusionary Multiple Modelling(EMM).Scientific thinking over IMMs is captured as a framework with four dimensions:Model Reuse(MR),Hierarchical Recursion(HR),Elastic Learning Environment(ELE)and Goal Orientation(GO)and these together make the acronym of RHEO.Therefore,IMM-RHEO is piloted in the aquifer of Tabriz Plain with sparse and possibly heterogeneous data.The results provide some evidence that(i)IMM at two levels improves on the accuracy of individual models;and(ii)model combinations in IMM practices bring‘model-learning’into fashion for learning with the goal to explain baseline conditions and impacts of subsequent management changes.
文摘Groundwater is important for managing the water supply in agricultural countries like Bangladesh. Therefore, the ability to predict the changes of groundwater level is necessary for jointly planning the uses of groundwater resources. In this study, a new nonlinear autoregressive with exogenous inputs(NARX) network has been applied to simulate monthly groundwater levels in a well of Sylhet Sadar at a local scale. The Levenberg-Marquardt(LM) and Bayesian Regularization(BR) algorithms were used to train the NARX network, and the results were compared to determine the best architecture for predicting monthly groundwater levels over time. The comparison between LM and BR showed that NARX-BR has advantages over predicting monthly levels based on the Mean Squared Error(MSE), coefficient of determination(R^2), and Nash-Sutcliffe coefficient of efficiency(NSE). The results show that BR is the most accurate method for predicting groundwater levels with an error of ± 0.35 m. This method is applied to the management of irrigation water source, which provides important information for the prediction of local groundwater fluctuation at local level during a short period.
文摘Groundwater resources provide most of the domestic water supply in rural Zimbabwe and support poverty reduction through irrigation facilities. Most agricultural and environmental plans need water table depth analysis as an input in designing best management strategies. There are limited direct measurements of groundwater levels in Zimbabwe due to high costs and the limited human expertise. The study is aimed at coming up with a proof of concept that altitude of rivers as determined by an SRTM digital elevation model can be used to estimate the levels of groundwater in parts of Mutirikwi and Runde sub catchments of southern Zimbabwe. The study also maps the groundwater levels of the area as determined by river altitude from the digital elevation model. Firstly, the groundwater levels for nine boreholes are measured. Secondly, the altitude of a river bed nearest to each borehole site is extracted from a digital elevation model. Finally, the Spearman’s correlation coefficient is used to determine the nature and strength of the relationship between the two variables. Linear regression analysis was also used to obtain the predictive equation of the relationship and its coefficient of determination. After the relationship between groundwater and river altitude is established, 9 new random points of river altitude are generated across the study area interpolated using kriging interpolation to give the estimated altitude of river altitude. The altitude of groundwater is then determined by running the predictive equation Y = 0.8736 * X + 0.852 obtained from regression analysis. The depth to groundwater level of area is obtained by subtracting the determined groundwater altitude from the SRTM DEM. The results show strong positive and statistically significant (ρ = 0.000, α = 0.01) correlation coefficient of 0.971 between measured groundwater levels and altitude of rivers. The regression model shows a coefficient of determination (r2) of 0.975. The research therefore determines that altitude of rivers and use of geostatistics can produce physically plausible estimates of groundwater levels in the study area.
文摘Climate change and increasing anthropogenic activities,such as over-exploitation of groundwater,are exerting unavoidable stress on groundwater resources.This study investigated the spatio-temporal variation of depth to groundwater level(DGWL)and the impacts of climatic(precipitation,maximum temperature,and minimum temperature)and anthropogenic(gross district product(GDP),population,and net irrigated area(NIA))variables on DGWL during 1994-2020.The study considered DGWL in 113 observation wells and piezometers located in arid western plains(Barmer and Jodhpur districts)and semi-arid eastern plains(Jaipur,Ajmer,Dausa,and Tonk districts)of Rajasthan State,India.Statistical methods were employed to examine the annual and seasonal patterns of DGWL,and the generalized additive model(GAM)was used to determine the impacts of climatic and anthropogenic variables on DGWL.During 1994-2020,except for Barmer District,where the mean annual DGWL was almost constant(around 26.50 m),all other districts exhibited increase in DGWL,with Ajmer District experiencing the most increase.The results also revealed that 36 observation wells and piezometers showed a statistically significant annual increasing trend in DGWL and 34 observation wells and piezometers exhibited a statistically significant decreasing trend in DGWL.Similarly,32 observation wells and piezometers showed an statistically significant increasing trend and 37 observation wells and piezometers showed a statistically significant decreasing trend in winter;33 observation wells and piezometers indicated a statistically significant increasing trend and 34 had a statistically significant decreasing trend in post-monsoon;35 observation wells and piezometers exhibited a statistically significant increasing trend and 32 observation wells and piezometers showed a statistically significant decreasing trend in pre-monsoon;and 36 observation wells and piezometers reflected a statistically significant increasing trend and 30 observation wells and piezometers reflected a statistically significant decreasing trend in monsoon.Interestingly,most of the observation wells and piezometers with increasing trends of DGWL were located in Dausa and Jaipur districts.Furthermore,the GAM analysis revealed that climatic variables,such as precipitation,significantly affected DGWL in Barmer District,and DGWL in all other districts was influenced by anthropogenic variables,including GDP,NIA,and population.As a result,stringent regulations should be implemented to curb excessive groundwater extraction,manage agricultural water demand,initiate proactive aquifer recharge programs,and strengthen sustainable management in these water-scarce regions.
文摘Adequate regional groundwater assessment studies are essential for the correct groundwater management by policy/decision makers; increased use of groundwater resources and drought have led to concern about the future availability of groundwater to meet domestic, agricultural, industrial, and environmental needs. Deep understanding of spatial and temporal water table dynamics together with transport processes is required. This paper gathers historical geological, hidrological and chemical information for quantitative and qualitative as well as spatial and temporal evolution of groundwater for Aguanaval and Chupaderos aquifers, both surrounding Calera aquifer in Mexico. Historical databases were employed to determine temporal trends of water levels and values were projected for years 2010, 2030 and 2050. Potential recharge sites were also identified through water level-topography correlation. The water quality analysis was completed by obtaining, through geostatistics, spatial distributions for bicarbonate, chloride, sulfate, total dissolved solids, temperature, and sodium, employing databases generated in recent sampling campaigns. This analysis provided additional elements to help understand the functioning of groundwater in studied aquifers. Finally, results were compared with permissible values established in the Mexican norm.
基金funded by the National Natural Science Foundation of China(9102500230970492)+2 种基金the Fundamental Research Funds for the Central Universities(GK201101002)the Key Project of the Chinese Academy of Sciences(KZZDEW-04-05)the National Key Technology R & D Program(2012BAC08B05)
文摘This paper, based on the analysis and calculation of the groundwater resources in an arid region from 1980 to 2001, put forward the concept of ecological groundwater level threshold for either salinity control or the determination of ecological warning. The surveys suggest that soil moisture and soil salinity are the most important environmental factors in determining the distribution and changes in vegetation. The groundwater level threshold of ecological warning can be determined by using a network of groundwater depth observation sites that monitor the environmental moisture gradient as reflected by plant physiological characteristics. According to long-term field observations within the Ejin oases, the groundwater level threshold for salinity control varied between 0.5 m and 1.5 m, and the ecological warning threshold varied between 3.5 m and 4.0 m. The quantity of groundwater re- sources (renewable water resources, ecological water resources, and exploitable water resources) in arid areas can be calculated from regional groundwater level information, without localized hydrogeological data. The concept of groundwater level threshold of ecological warning was established according to water development and water re- sources supply, and available groundwater resources were calculated. The concept not only enriches and broadens the content of groundwater studies, but also helps in predicting the prospects for water resources development.
基金National 973 Program for Basic Research No.G1999043506
文摘Sampling and testing are conducted on groundwater depth and vegetation coverage in the 670 km2 of the Sangong River Basin and semi-variance function analysis is made afterwards on the data obtained by the application of geo-statistics. Results showed that the variance curve of the groundwater depth and vegetation coverage displays an exponential model. Analysis of sampling data in 2003 indicates that the groundwater depth and vegetation coverage change similarly in space in this area. The Sangong River Basin is composed of upper oasis, middle ecotone and lower sand dune. In oasis and ecotone, influenced by irrigation of the adjoining oasis, groundwater level has been raised and soil water content also increased compared with sand dune nearby, vegetation developed well. But in the lower reaches of the Sangong River Basin, because of descending of groundwater level, soil water content decreased and vegetation degenerated. From oasis to abandoned land and desert grassland, vegetation coverage and groundwater level changed greatly with significant difference respectively in spatial variation. Distinct but similar spatial variability exists among the groundwater depth and vegetation coverage in the study area, namely, the vegetation coverage decreasing (increasing) as the groundwater depth increases (decreases). This illustrates the great dependence of vegetation coverage on groundwater depth in arid regions and further implies that among the great number of factors affecting vegetation coverage in arid regions, groundwater depth turns out to be the most determinant one.
基金This paper was supported by Natural Science Basic Research Program of Shaanxi Province,China(2019JLZ-03).
文摘Groundwater of Luohe Formation is the main water source for industrial and agricultural and residential use in Binchang mining area,which is one of the key elements to water conservation coal mining.However,few studies are available to document the enrichment characteristics and influence of underground coal mining on groundwater for the Luohe Formation.This study evaluates the changes of groundwater levels and spring flow caused by mining activities to explore the influence mechanism of coal mining on groundwater by comparatively analysing existing mining data and survey data combined with a series of mapping methods.The results show that the aquifer of Luohe Formation are gradually thinning south-eastwards,disappeared at the mining boundary.In the vertical direction,the lithological structure is distinct,due to alternative sedimentation of meandering river facies and braided river facies.According to the yielding property,the aquifer is divided into three sections,namely,strong water-rich section,medium water-rich section,and weak water-rich section,which are located in northwest and central part,southwest,and the rest part of the mining area,respectively.Mining of Tingnan Coal Mine since 2004 has caused a 3.16 to 194.87 meters drop in groundwater level of Luohe Formation.Until 2015,70.10%of the mining area undergoes a groundwater level drop larger than 10.00 meters.Another influence of underground mining is that the total flow from 34 springs in 8 southern coal mines of the area has decreased by 286.48 L/s with a rate of decrease at 46.95%from 2007 to 2017.The areas that groundwater level falls or spring flow declines are manly located in the mine gob areas.Results also indicate that the ratio of the height of water conducted fracture zone to the mining height in Binchang mining area is between 16.85 and 27.92.This may increase ground water flow in vertical direction,causing a water level in the aquifer system to drop and ultimately decreasing the flow from the springs.The research results will provide data and theoretical support for the protection of groundwater resources and water conservation coal mining of Luohe Formation in Binchang mining area.
基金This research was supported by the National Natural Science Foundation of China(41672250,42177076)the Natural Science Foundation of Shaanxi Province(2019JLZ-03)the Key R&D Projects of Shaanxi Province(2021ZDLSF05-09).
文摘At present,investigation about the relationship between the change of groundwater level and vegetation mostly focuses on specific watersheds,i.e.limited in river catchment scale.Understanding the change of groundwater level on vegetation in the basin or large scale,be urgently needed.To fill this gap,two typical arid areas in the west of China(Tarim Basin and Qaidam Basin)were chosen the a typical research area.The vegetation status was evaluated via normalization difference vegetation index(NDVI)from 2000 to 2016,sourced from MODN1F dataset.The data used to reflect climate change were download from CMDSC(http://data.cma.cn).Groundwater level data was collected from monitor wells.Then,the relationship of vegetation and climate change was established with univariate linear regression and correlation analysis approach.Results show that:Generally,NDVI value in the study area decreased before 2004 then increased in the research period.Severe degradation was observed in the center of the basin.The area with an NDVI value>0.5 decreased from 12%to 6%between 2000 and 2004.From 2004 to 2014,the vegetation in the study area was gradually restored.The whole coverage of Qaidam Basin was low.And the NDVI around East Taigener salt-lake degraded significantly,from 0.596 to 0.005,2014 and 2016,respectively.The fluctuation of groundwater level is the main reason for the change of surface vegetation coverage during the vegetation degradation in the basin.However,the average annual precipitation in the study area is low,which is not enough to have a significant impact on vegetation growth.The annual average precipitation showed an increase trend during the vegetation restoration in the basin,which alleviates the water shortage of vegetation growth in the region.Meanwhile,the dependence of surface vegetation on groundwater is obviously weakened with the correlation index is−0.248.The research results are of some significance to eco-environment protection in the arid area of western China.
基金This work was supported by the National Natural Science Foundation of China(41672243)the China Geological Survey Program(DD20160291,DD20189270).
文摘Delingha is located in the northeast margin of Qaidam Basin.Bayin River alluvial proluvial fan is the main aquifer of Delingha,in which groundwater generally flows from north to south.The hydrochemistry results showed that two different hydrochemical evolution paths formed along southeast and southwest directions,respectively.Cl-Na type groundwater was formed in front of Gahai Lake,and SO_(4)·HCO_(3)-Na·Ca type groundwater was formed in front of Keluke Lake.The results of deuterium(D)and 18O revealed that the groundwater mainly originated from the continuous accumulation of precipitation during geological history under cold and humid climate conditions.In addition,results of ^(14)C indicated that the groundwater age was more than 1140 years,implying relatively poor renewal capability of regional groundwater.Moreover,our numerical modeling results showed that the regional groundwater level will continue to rise under the warm and humid climate conditions.
基金This research used data and documents from the project“Planning the ground level and urban surface water drainage in Binh Duong Province”.We sincerely thank the organizations related to this project.
文摘The purpose of this paper was to assess the impact of urbanization on the groundwater level(GWL)in aquifers of Binh Duong(BD)Province.The research method is to analyze the trend of GWL,the recharge capacity of surface over time and the relationship between them.The data of the GWL used in the study are the average values in the dry and rainy seasons of 35 observation wells from 2011 to 2018,which are in Pleistocene and Pliocene aquifers.The ability to recharge groundwater from the surface in this study was represented by the curve number(CN),a parameter used in hydrology for calculating direct runoff or infiltration from rainfall.The land use data to identify the CN was analyzed from the Landsat images.The results show that besides over-exploitation,the change of surface characteristic due to the urbanization development process is also the cause of the GWL decline.The analysis of seasonal GWL data shows that the increase in impervious surface area is the cause of GWL decline in the Pleistocene aquifer,which is more evident in the rainy season than in the dry season.The statistical results also show that in the rainy season and in shallow aquifers,a higher CN change can be found with the wells that had a remarkable GWL decline compared to the remaining wells.
文摘The shallow groundwater in Shendong mining area was broken because of large-scale underground mining activities. Selecting 32201 working-face as research area, analyzed the change rule of groundwater level and aquifer thickness under mining impact with a large number of water level observation data. Then, the impacts of groundwater level change on vegetation were analyzed by the relationship theory of arid area groundwater and vegetation. The results show that the aquifer structure and the water condition of supply flow and drainage are changed by the water proof mining. The groundwater level recovere only a little compared with the original groundwater level in two years. But the great change of groundwater level do not have notable influences on vegetation of this mining area, and further study indicates that there are certain conditions where groundwater level change impacted on vegetation. When the influence of groundwater level change was evaluated, the plant ecological water level, warning water level and spatial distribution character of original groundwater and mining-impacted groundwater-level change should be integrated.
基金supported by the China Earthquake Administration, Institute of Seismology Foundation (IS201526246)
文摘According to groundwater level monitoring data of Shuping landslide in the Three Gorges Reservoir area, based on the response relationship between influential factors such as rainfall and reservoir level and the change of groundwater level, the influential factors of groundwater level were selected. Then the classification and regression tree(CART) model was constructed by the subset and used to predict the groundwater level. Through the verification, the predictive results of the test sample were consistent with the actually measured values, and the mean absolute error and relative error is 0.28 m and 1.15%respectively. To compare the support vector machine(SVM) model constructed using the same set of factors, the mean absolute error and relative error of predicted results is 1.53 m and 6.11% respectively. It is indicated that CART model has not only better fitting and generalization ability, but also strong advantages in the analysis of landslide groundwater dynamic characteristics and the screening of important variables. It is an effective method for prediction of ground water level in landslides.
基金funded by Geological survey project of China Geological Survey (DD20190336, DD20221752)。
文摘The Beijing-Tianjin-Hebei Plain(BTHP)is the political,economic and cultural center of China,where groundwater is the main source of water supply to support social and economic development.Continuous overdraft of the resources has caused a persistent decline of groundwater level and formed a huge cone of depression at a regional scale.This paper addresses current groundwater situation over the BTHP area.The paper also delineates the groundwater flow field,using groundwater level data,in order to provide an effective method for the restoration of groundwater level and associated water resources management.Based on the analysis of multiple factors,such as groundwater level,soil salinization,ground subsidence,groundwater recharge and storage,urban underground space security,formation of fractures,and seawater intrusion,the threshold for groundwater level restoration is defined,and some measures for groundwater over-exploitation management are accordingly proposed.The study shows that:(i)Since the 1980s to 2020,shallow groundwater level in the western part of the BTHP area has dropped by 25 m to 60m,while the cumulative decline of deep groundwater in the central and eastern regions is in the range of 40–80 m;(ii)The water table of the shallow groundwater within the depression zone over the Western Piedmont Plain should be controlled in the range of 15–30 m below ground level(mbgl),while the depth of groundwater level in large and medium-sized urban areas should be controlled within 20–30 mbgl.The groundwater level in the resource preservation area should be controlled within 10–15 mbgl,and the groundwater level in the area with identified soil salinization in the central and eastern plain should be controlled within 3–10 mbgl.However,for the deep groundwater in the central and eastern plainwater,the main focus of the resources management is to control the land subsidence.The water level in the severe land subsidence area should be controlled within 45–60 mbgl,and in the general subsidence area should be controlled within 30–45 mbgl;(iii)Based on the water level recovery threshold and proposed groundwater overdraft management program,if the balance of abstraction and recharge is reached in 2025,the shallow groundwater abstraction needs to be gradually reduced by about 2×10^(8) m^(3).Meanwhile,the ecological water replenishment of rivers through the South-to-North Water Transfer Project should be increased to 28.58×10^(8) m^(3)/a,and the deep groundwater abstraction needs to be gradually reduced by 2.24×10^(8) m^(3).To reach the target of shallow groundwater level in 2040,surface water replacement is recommended with a rate of 25.77×10^(8) m^(3)/a and the ecological water replenishment of rivers in the South-to-North Water Diversion Project should reach 33.51×10^(8) m^(3)/a.For deep groundwater recovery,it is recommended to replace the deep freshwater extraction with the utilization of shallow salt water by 2.82×10^(8) m^(3),in addition to the amount of 7.86×10^(8) m^(3) by water diversion.The results are of great significance to the remediation of groundwater over-exploitation,the regulation of water resources development and utilization,and ecological protection in Beijing-Tianjin-Hebei plain.
文摘As the traditional non-linear systems generally based on gradient descent optimization method have some shortage in the field of groundwater level prediction, the paper, according to structure, algorithm and shortcoming of the conventional radial basis function neural network (RBF NN), presented a new improved genetic algorithm (GA): hybrid hierarchy genetic algorithm (HHGA). In training RBF NN, the algorithm can automatically determine the structure and parameters of RBF based on the given sample data. Compared with the traditional groundwater level prediction model based on back propagation (BP) or RBF NN, the new prediction model based on HHGA and RBF NN can greatly increase the convergence speed and precision.
基金supported by the National Natural Science Foundation of China under grants No. 41272269
文摘Abandoned mines are of high potential risk as they could be a large underground storage of pollutants(heavy metals and organic wastes, etc.). Various physical, chemical and biological reactions would take place when groundwater flows into underground spaces, which makes abandoned mine a huge potential hazard to groundwater environment. The recovery of groundwater level is one of the key elements controlling the reactions and causing such hazards. This paper simulated groundwater level recovery processes in the abandoned mines, Fengfeng coalfield by using the computer program FEFLOW. The paper integrated the pipe flow model, "three zones" model and groundwater inrush(discharge) model in the simulation of groundwater in the complex laneway-aquifer system. Groundwater flow in the laneway systems was considered pipe flow and described in Bernoulli equation. The water-bearing medium(coal seam roof) overlying the laneway systems was divided into "three zones" composed of the caving zone, fissure zone and bending zone based on the disruption degrees of previous mining. Groundwater in the Ordovician limestone aquifer(bottom of coal seam) flowing into laneway systems was considered a major inrush/recharge source, and its flow rate was calculated by an inrush(discharge) model which was newly developed in this study and incorporated into FEFLOW. The results showed that it would take approximately 95 days for groundwater in abandoned mines to recover to regional groundwater level elevation, and the total amount of water filling up would be about 1.41195×10~7 m^3, which is consistent with the actual data. The study could be of theoretical and practical significance to mitigate abandoned mines' hazards and improve mine groundwater utilization.
文摘Stochastic modelling of hydrological time series with insufficient length and data gaps is a serious challenge since these problems significantly affect the reliability of statistical models predicting and forecasting skills.In this paper,we proposed a method for searching the seasonal autoregressive integrated moving average(SARIMA)model parameters to predict the behavior of groundwater time series affected by the issues mentioned.Based on the analysis of statistical indices,8 stations among 44 available within the Campania region(Italy)have been selected as the highest quality measurements.Different SARIMA models,with different autoregressive,moving average and differentiation orders had been used.By reviewing the criteria used to determine the consistency and goodness-of-fit of the model,it is revealed that the model with specific combination of parameters,SARIMA(0,1,3)(0,1,2)_(12),has a high R^(2) value,larger than 92%,for each of the 8 selected stations.The same model has also good performances for what concern the forecasting skills,with an average NSE of about 96%.Therefore,this study has the potential to provide a new horizon for the simulation and reconstruction of groundwater time series within the investigated area.
基金This project was supported by the National Natural Science Foundation of China (10371012)
文摘Many factors can cause changes of groundwater level,such as the development process of an earthquake,rainfall,solid earth tides etc.Among these we are interested in information regarding earthquake development processes.Eliminating the influence of various disturbance factors is an effective way to obtain seismic development process information contained in the groundwater level.This paper provides two different ways to remove the rainfall effect,and compares the two methods by means of correlation analysis.Furthermore,based on these a logistic regression model is established to describe the seismicity level.
文摘The variations in both precipitation and temperature have far-reaching effects on agricultural activities and the accessibility of water resources. These climatic parameters are pivotal in determining the availability of both groundwater and surface water for agricultural use. The aim of this study was to evaluate the variations in climate parameters, focusing on precipitation and temperature, alongside changes in cultivated land area and crop yields in the Tadla area (Béni Mellal Khénifra region, Morocco);additionally, our research looks at the changes in water inflow into two dams and four aquifers. Trends were assessed over the period of 2010-2020 using the standardized precipitation index (SPI) method, as well as the parametric regression method and nonparametric Mann-Kendall and Sen’s slope test. This analysis can be a preliminary step in demonstrating the effects of climate variability on water resource availability and its adverse impacts on agriculture in the region. The results showed a decreasing trend for some yield crops despite the increase in the cultivated area. The results of the groundwater levels and inflow dams showed a significant upward evolution. The analysis of the obtained SPI values and temperatures has revealed a notable and consistent upward trendencies. This upward trajectory indicates that both the SPI values, which reflect precipitation patterns and the temperatures, have been on the rise over the examined period. These results prompt reflection on the effects of climate variability on water resources in the region and economic activities, particularly agriculture.