ASSESSMENT OF LONG-TERM AND RECENT GROUNDWATER LEVEL RECORDS IN WISCONSIN FROM 1917 TO 2017

2018 ◽  
Author(s):  
Duabchi Vang ◽  
◽  
Emily M. Finger ◽  
Sarah A. Vitale
Keyword(s):  
Groundwater Level

scholarly journals Study of the Long-term Change of Groundwater Level and Water Quality in the Vicinity of a Dam

1996 ◽  
Vol 40 ◽  
pp. 93-100
Author(s):  
Isao SHIOZAKI ◽  
Fusetsu TAKAGI ◽  
Uichiro MATSUBAYASHI ◽  
Hiromi KOJO
Keyword(s):  
Water Quality ◽  
Groundwater Level ◽  
Term Change

scholarly journals Assessing the long-term sustainability of the groundwater resources in the Bacchiglione basin (Veneto, Italy) with the Mann–Kendall test: suggestions for higher reliability

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Mara Meggiorin ◽  
Giulia Passadore ◽  
Silvia Bertoldo ◽  
Andrea Sottani ◽  
Andrea Rinaldo
Keyword(s):  
Groundwater Level ◽  
Water Cycle ◽  
Groundwater Resources ◽  
Sustainable Use ◽  
Kendall Test ◽  
Groundwater System ◽  
Aquifer System ◽  
Mann Kendall Test ◽  
Status Assessment

The social, economic, and ecological importance of the aquifer system within the Bacchiglione basin (Veneto, IT) is noteworthy, and there is considerable disagreement among previous studies over its sustainable use. Investigating the long-term quantitative sustainability of the groundwater system, this study presents a statistical methodology that can be applied to similar cases. Using a combination of robust and widely used techniques, we apply the seasonal Mann–Kendall test and the Sen’s slope estimator to the recorded groundwater level timeseries. The analysis is carried out on a large and heterogeneous proprietary dataset gathering hourly groundwater level timeseries at 79 control points, acquired during the period 2005–2019. The test identifies significant decreasing trends for most of the available records, unlike previous studies on the quantitative status of the same resource which covered the domain investigated here for a slightly different period: 2000–2014. The present study questions the reason for such diverging results by focusing on the method’s accuracy. After carrying out a Fourier analysis on the longest available timeseries, for studies of groundwater status assessment this work suggests applying the Mann–Kendall test to timeseries longer than 20 years (because otherwise the analysis would be affected by interannual periodicities of the water cycle). A further analysis of two 60-year-long monthly timeseries between 1960 and 2020 supports the actual sustainable use of the groundwater resource, the past deployment of the groundwater resources notwithstanding. Results thus prove more reliable, and meaningful inferences on the longterm sustainability of the groundwater system are possible.

scholarly journals Analysis of long-term observations of the groundwater level In an aseismic region

2019 ◽  
pp. 47-67
Author(s):  
A. A. Lyubushin ◽  
O. S. Kazantseva ◽  
A. B. Manukin
Keyword(s):  
Time Series ◽  
Groundwater Level ◽  
Atmospheric Pressure ◽  
Active Regions ◽  
Sampling Interval ◽  
Pressure Effects ◽  
Adaptive Compensation ◽  
Groundwater Level Fluctuations ◽  
And Cluster Analysis

The results of the analysis of continuous precise time series of atmospheric pressure and groundwater level fluctuations in a well drilled to a depth of 400 m in the territory of Moscow are presented. The observations are remarkable in terms of their duration of more than 22 years (from February 2, 1993 to April 4, 2015) and by the sampling interval of 10 min. These long observations are suitable for exploring the stationarity of the properties of hydrogeological time series in a seismically quiet region, which is important from the methodological standpoint for interpreting the similar observations in seismically active regions aimed at earthquake prediction. Factor and cluster analysis applied to the sequence of multivariate vectors ofthe statistical properties of groundwater level time series in the successive 10-day windows after adaptive compensation for atmospheric pressure effects distinguish five different statistically significant states of the time series with the transitions between them. An attempt to geophysically interpret the revealed states is made. Two significant periods – 46 and 275 days – are established by spectral analysis of the sequence of the transitions times between the clusters.

Rescue of groundwater level time series: how to identify and treat errors

2021 ◽  
Author(s):  
Jānis Bikše ◽  
Inga Retike ◽  
Andis Kalvāns ◽  
Aija Dēliņa ◽  
Alise Babre ◽  
...  
Keyword(s):  
Time Series ◽  
Groundwater Level ◽  
Monitoring Network ◽  
Observation Data ◽  
Automatic Data ◽  
Mean Values ◽  
Temporal Prediction ◽  
National Monitoring ◽  
Groundwater Drought

<p>Groundwater level time series are the basis for various groundwater-related studies. The most valuable are long term, gapless and evenly spatially distributed datasets. However, most historical datasets have been acquired during a long-term period by various operators and database maintainers, using different data collection methods (manual measurements or automatic data loggers) and usually contain gaps and errors, that can originate both from measurement process and data processing. The easiest way is to eliminate the time series with obvious errors from further analysis, but then most of the valuable dataset may be lost, decreasing spatial and time coverage. Some gaps can be easily replaced by traditional methods (e.g. by mean values), but filling longer observation gaps (missing months, years) is complicated and often leads to false results. Thus, an effort should be made to retain as much as possible actual observation data.</p><p>In this study we present (1) most typical data errors found in long-term groundwater level monitoring datasets, (2) provide techniques to visually identify such errors and finally, (3) propose best ways of how to treat such errors. The approach also includes confidence levels for identification and decision-making process. The aim of the study was to pre-treat groundwater level time series obtained from the national monitoring network in Latvia for further use in groundwater drought modelling studies.</p><p>This research is funded by the Latvian Council of Science, project “Spatial and temporal prediction of groundwater drought with mixed models for multilayer sedimentary basin under climate change”, project No. lzp-2019/1-0165.</p>

Analysis of Long-Term Observations of the Groundwater Level in an Aseismic Region

2019 ◽  
Vol 55 (2) ◽  
pp. 232-249
Author(s):  
A. A. Lyubushin ◽  
O. S. Kazantseva ◽  
A. B. Manukin
Keyword(s):  
Groundwater Level

Complex landslide dynamics: establishing a monitoring setup to investigate sub-surface properties and displacements of a slow moving landslide system

2020 ◽  
Author(s):  
Margherita J. Stumvoll ◽  
Robert Fahrngruber ◽  
Thomas Glade
Keyword(s):  
Spatial Distribution ◽  
Soil Moisture ◽  
Data Analysis ◽  
Soil Water ◽  
Surface Properties ◽  
Groundwater Level ◽  
Direct Methods ◽  
Time Domain Reflectometry ◽  
Non Invasive

<p>Quantitative data of the sub-surface properties and dynamics of recently active landslides spanning a temporal scale of more than a few years are still fairly rare. This is due to the fact that long-term landslide-monitoring setups are expensive regarding both financial and human resources as well as to install and maintain. Yet, a comprehensive understanding of potential landslide triggering thresholds is mandatory. <br>Apart from external triggers the internal hydrological, soil mechanical and geophysical properties of a hillslope determine its potential for displacement. The spatial distribution of groundwater levels and soil water contents as well as of the regolith material, resistance and depth define potential areas of activity. The internal structure of a landslide needs to be assessed in order to be able to evaluate magnitude and frequency as well as potential triggers of activity.</p><p>In this study, we present a long-term monitoring setup for the detection of sub-surface properties, structure and dynamics of the complex Hofermühle-landslide near Konradsheim in Lower Austria. A combination of direct (invasive) and indirect (non-invasive) methods is used. Direct methods include 1) dynamic probing to investigate sub-surface resistance and 2) the analysis of cores generated via drilling. Data analysis hereby focus on geotechnical parameters such as soil properties, regolith depth and resistance. To investigate hydrological properties data regarding 3) groundwater level using piezometers as well as 4) soil moisture using time domain reflectometry (TDR) probes are used. Data analysis focus on the spatio-temporal behaviour of soil moisture and groundwater level changes in order to assess sub-surface water pathways, water residence time and the connection to changes – regarding both input (precipitation) and output (evapotranspiration). Sub-surface movement rates and their position along vertical soil profiles are planned to be analysed using 5) inclinometer data. Direct methods are combined with non-invasive geophysical methods. As this monitoring setup will be maintained for a longer time period (>10a), the setup itself is assessed critically; challenges and issues of the installation, data transfer and analysis are discussed.</p><p>First results regarding the analysis of hydrological parameters indicate a heterogenic distribution of groundwater static level, soil water retention time after infiltration and flow paths. A first interpretation of the sediment core, dynamic probing as well as geophysical results support this heterogeneity. Sub-surface areas of potential activity could be presumed to be correlated with the spatial distribution of surface displacements as these also show a heterogenic distribution.</p>

scholarly journals FEATURES OF THE FORECAST OF THE DYNAMICS OF SPRING FLOW ON THE COASTAL ZONE OF IVANKOVO RESERVOIR

2020 ◽  
Vol 31 (1-2) ◽  
pp. 79-89
Author(s):  
E.E. Lapina ◽  
◽  
L.E. Lapina ◽  
Keyword(s):  
Statistical Analysis ◽  
Water Content ◽  
Coastal Zone ◽  
Flow Rate ◽  
Groundwater Level ◽  
Chronological Order ◽  
Arithmetic Average ◽  
Ivankovo Reservoir ◽  
Calcium And Magnesium

Ivankovo reservoir is the main source of drinking water supply in Moscow. Its coastal zone, where different types of springs are unloaded, is a barrier (or source) for the entry of pollutants into the reservoir. The aim of this research is to forecast increments in descending springs water flow and to evaluate trends of hydrochemical indicators (calcium, magnesium ions, hydrocarbonates and chlorine) of springs water quality over 13 years. The basis of the work are materials of regime observations on reference spring located on the Volga II floodplain terrace, for the period 2006-2018. When processing hydrochemical data in order to compare the results, two approaches were used. One is separation of data array into two groups in chronological order (2006-2012 and 2013- 2018), the other – is arrangement according to water content of the year, where the first group is the years of low and medium water content, the second is high. It is proposed to describe the relationship between amount of precipitation and increment of flow rate by an ordinary differential equation, which will allow to predict the flow rate of the downstream springs of the region using amount of precipitation in increments by the next six months. The obtained result was verified on groundwater level regime data for the well 3020, drilled on the II floodplain terrace, for the period 2001-2003. The maximum correlation coefficient between the increment of the groundwater level and the amount of precipitation is observed at a similar step. When analyzing the equation, the value of the amount of precipitation was obtained, which separates the mode of increasing or decreasing the flow rate of the spring (groundwater level). For the spring, this figure is 296, for the well – 316 mm. A statistical analysis of long-term dynamics of the spring runoff hydrochemical components showed that a median value is a more sensitive characteristic to changes in external conditions than an arithmetic average for hydrocarbonates and calcium. An upward direction shift of the median value of bicarbonates and calcium ions concentration in spring waters was revealed when using a nonparametric criterion. The long-term average gradient was 1 mg dm-3 year-1 for bicarbonates, and 0.17 mg dm-3 year-1 for calcium. The approaches used to divide the data into groups for calcium and magnesium give different estimates of trends, for hydrocarbons they were the same, for chlorides they are contradictory. Statistical analysis of the data, separated in chronological order, showed that for calcium and magnesium there was a significant upward trend, while with the approach for water availability of year no trends were found.

scholarly journals Spatiotemporal Variation of the Meteorological and Groundwater Droughts in Central Taiwan

2021 ◽  
Vol 3 ◽  
Author(s):  
Hsin-Fu Yeh
Keyword(s):  
River Basin ◽  
Groundwater Level ◽  
Standardized Precipitation Index ◽  
Extreme Drought ◽  
Water Shortages ◽  
Level Data ◽  
Groundwater Drought ◽  
Central Taiwan ◽  
The Standardized Precipitation Index

In recent years, Taiwan has been facing severe water shortages due to extreme drought. In addition, changes in rainfall patterns have resulted in an increasingly notable drought phenomenon, which affects the management and utilization of water resources. Therefore, this work examines basins in Central Taiwan. Long-term records from 13 rainfall and 17 groundwater stations were selected. The Standardized Precipitation Index (SPI) and Standardized Groundwater Level Index (SGI) were used to analyze the drought characteristics of this region. The rainfall and groundwater level data from basins in Central Taiwan were analyzed in this study. The results show that the year 2015 experienced extreme drought conditions due to a correlation with SPI and SGI signals. In addition, with regard to groundwater drought, more drought events occurred in the Da'an River basin; however, the duration and intensity of these events were relatively low, in contrast to those of the Wu River basin. Finally, the correlation between SPI and SGI was observed to vary in different basins, but a certain degree of correlation was observed in all basins. The results show that drought intensity increases with longer drought durations. Moreover, severe droughts caused by rainfall tend to occur at a greater frequency than those caused by groundwater.

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