High Groundwater Level Research Articles

Study on the Farmland Improvement Effect of Drainage Measures under Film Mulch with Drip Irrigation in Saline–Alkali Land in Arid Areas

Water scarcity and imbalances in irrigation and drainage are the main factors leading to soil salinization in arid areas. There is a recognized need for effective drainage measures to prevent and improve saline−alkali land. The principal objective of this project was to investigate the effects of drainage measures on soil desalination and farmland drainage in the process of improving saline–alkali soils; these measures included subsurface pipe drainage (SPD) and open ditch drainage (ODD). The results of the tests, conducted over two years, revealed that the soil desalination rate in the SPD test area was between 25.8% and 35.2%, the cotton emergence rate was 36.7%, and a 3.8 t hm−2 seed cotton yield could be obtained. The soil electrolytic conductivity (EC) decreased step by step over time, and the average annual decrease reached 10 dS m−1. The degree of soil salinization was reduced from a moderately saline soil level (8−15 dS m−1) to a weakly saline soil level (4–8 dS m−1). Thus, the phased goal of improving saline–alkali land was achieved. The soil desalination rate in the ODD test area was only 1/10 of the SPD area; high soil EC (9−12 dS m−1) and groundwater level (2–3 m) were the most limiting factors affecting cotton growth in the ODD test area. The current results show that the critical depth of groundwater level affecting farmland secondary salinization is 4 m. In order to improve the salt discharge standard, SPD technology should be used on the basis of ODD. For salt that has accumulated in the soil for a long time, the technical mode of drip irrigation and leaching, followed by SPD drainage, in combination with the current irrigation system can achieve the goal of sustainable agriculture development.

Emissions of CO2, N2O and CH4 From Cultivated and Set Aside Drained Peatland in Central Sweden

Northern peatlands are important carbon (C) reservoirs, storing about one-third of the global terrestrial soil C pool. Anthropogenic influences, such as drainage for agriculture and forestry, lower the originally high groundwater level, leading to peat aeration and decomposition. This is particularly reflected in significant losses of CO2, while fluxes of N2O and CH4 are generally considered of minor importance for the overall greenhouse gas (GHG) balance of cultivated peatlands in Scandinavia. Setting land aside from agricultural production has been proposed as a strategy to reduce GHG emissions from drained peatland, restore natural habitats, and increase C sequestration. However, the evidence for this is rather scarce unless drainage is terminated. In this study, we measured respiration using dark automatic chambers, and CO2, N2O, and CH4 fluxes using manual static chambers, on: 1) cultivated peatland and 2) adjacent set-aside peatland in Central Sweden. The set-aside site was found to be a greater source of respiration than the cultivated site, while higher N2O fluxes and lower CH4 uptake rates were observed for the cultivated site. However, to compare the full GHG balance and assess the abandonment of drained cultivated peatland, additional measures, such as gross primary production (GPP) but also dissolved organic C losses would have to be taken into account.

Natural Resources Self-Sufficiency – How to Balance Groundwater Protection and Mineral Resources Exploitation – Pleterje Case, Slovenia: Legal and Geological Aspects

The purpose of this article is to showcase opportunities for local communities to demonstrate self-sufficiency with respect to natural resources (gravel and sand) in the east of Slovenia. Limitations put in place for the exploitation of mineral resources by applicable regulations in the light of groundwater protection were analysed particularly in the context of mining undertaken in an area of shallow alluvium with a shallow groundwater table. It is essential that land disturbance (from mining activity) complies with the environmental limitations imposed by both EU and Slovenian law. The study highlights the factors directly indicating the inadequacy of the applicable regulations in Slovenia in relation to mining in areas of shallow groundwater; those limitations put in place the exploitation of mineral resources as unlawful works. This article outlines how such limitations negatively affect local communities’ self-sufficiency and the region with natural resources, specifically mineral resources. To this end, when selecting which alluvial plain to test, we focused on the area of the Drava and Ptuj Plain (Dravsko polje and Ptujsko polje) in Slovenia. The Drava River flows through the area in question across this alluvial plain. The artificially regulated power canal of the Zlatoličje hydroelectric power plant runs parallel to the river. Pursuant to environmental regulations, mineral resources can be exploited in these areas only up to two metres above the highest groundwater level. This criterion makes it almost impossible to pursue the additional exploitation of mineral resources in this area, as well as similar areas in the catchment area of the Danube River in Slovenia. We believe that in terms of the shared use of physical space it is necessary to change this limitation and link it directly to the percentage of exploited physical space and the application of relevant extraction technologies, which do not pollute groundwater either directly or indirectly. We also believe that the criterion put in place does not withstand expert judgment as the requirement for excavation to cease up to two metres above the highest groundwater level was not defined by means of the scientific method. The article analyses inconsistencies and puts forward measures for the ongoing eco-friendly and economically sustainable exploitation of mineral resources. As an alternative, we thus suggest implementing the EU Regulation via an act that would set out the necessary limitations, based on expert starting points arising from cartographic bases under consideration of the tetrahedral consensus-seeking methodology.

A boundary model of terrain reconstruction in a coal-mining subsidence waterlogged area

Mining of coal resources in an area with a high groundwater level causes large-scale water accumulation on the surface, which brings great difficulties to land reclamation. To improve the reclamation efficiency, a boundary mathematical model of terrain reconstruction in the subsidence waterlogged area was established based on the Probability Integral Method (PIM) and the principle of equal amounts of digging and filling. The terrain reconstruction curve of deep-digging and shallow-filling was calculated through the linear combination of the surface’s predicted subsidence curve and the designed elevation line. The dividing boundary, inner boundary, and outer boundary of deep-digging and shallow-filling were defined. Finally, the whole subsidence area was divided into four different regions according to inflection points of the terrain reconstruction curve, and the ecological reconstruction schemes of agriculture, forestry, and fishery were put forward. The engineering practice of the 1013 panel in Wugou Coal Mine showed that 54.69%, 31.55%, and 13.76% of the subsided land were reclaimed for cultivated land, slope cultivated land, and aquaculture area, respectively, and all the subsided land was reasonably utilized. This method provides a new technology for eco-environment treatment in the subsidence area with a high groundwater level.

The Influence of Forest Management and Changed Hydrology on Soil Biochemical Properties in a Central-European Floodplain Forest

Anthropogenic modifications to water regimes are one of the main factors threatening the stability and existence of floodplain forests. This study presents an analysis of topsoil biogeochemistry within three floodplain forest stands with different levels of human alteration. Decreasing contents of soil organic carbon (OC) and microbial biomass were observed along the gradient from natural to plantation forest. High annual variations were observed in soil N contents and in microbial biomass, while comparable spatial variations were observed within the natural forest. High ground-water levels resulted in increased accumulation of available Na+ and SO42− in the natural forest soil, yet the concentrations of ions were at sub-saline levels. The increasing contents of available Mn, SO42− or Cl− had mostly positive effects on soil microbial activity across the sites, though the results indicate the existence of a certain ecological limit for soil microorganisms. Reintroduction of surface-water flooding should be considered in future forest and water management to promote the dilution of ions accumulated in soils and natural deposition of sediments rich in organic matter (OM) at the sites.

Structural Design of New Permeable Ecological Side Edge

The side ditch is a longitudinal ditch set up on both sides of the road cutting to collect and remove precipitation from the road surface, road shoulder and side slope. It is the most common drainage facility in highway construction. However, the existing side ditches are generally wide, large, and deep, with a single structure, and poor coordination with the environment along the line. For this reason, this paper proposes a new type of permeable ecological side ditch structure design. Under the premise of ensuring the basic functions of the side ditch, this design effectively solves the problem that the edge of the side ditch is susceptible to erosion due to accumulated rainwater or frost heave in the alpine areas with high groundwater level. At the same time, to maximize the strength of the side ditch and enhance its ecological function.

Experimental Study on Wharf yard Foundation Reinforced by Drain Board and Dynamic Consolidation Method

The intelligent reconstruction project of the old wharf yard faces the problems of soil layer uneven horizontal distribution, hard concrete shell layer on the surface and high groundwater level of the site. Improper treatment can easily induce uneven settlement of the foundation, which will affect the normal operation of the intelligent wharf. Based on the actual project, this paper carries out the experimental research on the dynamic consolidation effect of the foundation with or without the drain board, compares and analyzes the monitoring and detection results of the foundation under two working conditions, and gives the calculation formula of the effective consolidation depth. The results show that: the insertion of the drain board can quickly dissipate the excess pore water pressure caused by the dynamic consolidation construction, and effectively shorten the consolidation time of the soft soil foundation; Compared with the area without drain board, the effect of foundation reinforcement is more obvious in the drain board area, In the range of effective reinforcement depth, it is more conducive to improve the mechanical properties of soft clay layer; Groundwater level is an important factor affecting the effective reinforcement depth of dynamic consolidation foundation, in the coastal areas with high water level, reasonable and effective precipitation measures should be considered; The estimation range of effective reinforcement depth correction coefficient is given, which can provide a reference for the design and construction of foundation dynamic consolidation in similar sites.

The spatial distribution and expansion of subsided wetlands induced by underground coal mining in eastern China

A large number of subsided wetlands have formed in eastern China in areas with high-intensity mining. However, data are not currently available to indicate their spatial distribution and expansion in the past thirty years. This paper uses a modified normalized difference water index (mNDWI) and a maximum between-cluster variance (OTSU) image segmentation algorithm to extract the subsided wetlands in mining areas with high ground-water levels of eastern China from 1988 to 2018 based on Google Earth Engine. The results show that the overall accuracy of the extraction of subsided wetlands is 98%; the Kappa coefficient reached 0.81. The total area of subsided wetland in 2018 was 26,034.88 ha, of which 14,290.97 ha was in Anhui Province, accounting for 54.89% of all such wetlands. The spatial extent of subsided wetlands has grown rapidly in the past three decades with the area of subsided wetlands expanding by 11.86 times from 1988 to 2018. The total area of subsided wetlands in the winter of 2018 was 25,296.25 ha, which was smaller than in summer. This indicates that seasonal precipitation affects the spatial extent of subsided wetlands. Although some restoration activities have been successful, most of the subsided wetlands still need active development and management. In conclusion, mNDWI and OTSU image segmentation algorithms could quickly and accurately allow the extraction of the spatial extent of subsided wetlands. Subsided wetlands have strong potential for development in future ecological restoration. The ecosystem services of wetlands and availability of dynamic monitoring technology should be considered important in the future.

Manufacturing of Machine for Planting on Wide Ridges Without Tillage in Desert Soils

This research was conducted during three winter seasons (2015-2016), (2016-2017) and (2017-2018) at Ras Sudr Research Station, South of Sinai Governorate, this region suffers from the problems of increasing salinity in soil and irrigation water, in addition to the high level of ground water. Therefore, the cultivation on wide ridges (raised-bed soil) was used for good soil leaching by storing large quantities of irrigation water in these wide ridges and easy drainage it from both sides of the ridges to the adjacent furrows. The wide ridges are considered one of the methods of remedy the rise in ground water level by raising the agricultural soil to a higher level, which helps to move the roots of plants away from the ground water level and to drain the irrigation water through the ridges sides to the adjacent furrows, which does not cause an increase in the ground water level. Also, conservation tillage (no-tillage) reducing the effect of salinity. So that a prototype of combined machine was manufactured which consisted of two units, the first unit to build ridges with the possibility to change the both of width and height of ridges. The second unit to sow wheat seeds on the ridges. The research treatments consisted of two tillage systems (traditional tillage system (TT) and conservation tillage system (CT) i.e., no-tillage), three ridge widths (50cm, 70cm and 90cm) and four ridge heights (0cm, 20cm, 35cm and 50 cm) where, the treatment of (0cm) was indicated to control treatment (flat soil). Also, the effect of three agriculture seasons was studied. Some parameters were measured or estimated as the following; actual field capacity (AFC), field efficiency (FE)), energy requirements (ER), pulling force (PF), fuel consumption rate (FCR), bulk density (BD), average infiltration rate (AIR), soil salinity (SS), water stored in the effective root zone (WS), water consumptive use in root zone (WC), water application efficiency (WA), wheat grain yield (WGY), water productivity (WP) and specific cost of production (SC). When using (CT) system and the largest cross section area of the ridges (90cm width x 50cm height) with continued application of this system for three consecutive seasons achieved the highest values of: (AFC=0.39 ha/h), (FE=93%), (WS=5773 m3/ha), (WC=4834 m3/ha), (WA=89%), (WGY=8.7 Mg/ha) and (WP=1.8 Mg/m3), in addition this treatment achieved the lowest values for both (SS=6.17 ds/m) and (SC=216 L.E/Mg) compared to the other treatments.

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According to the conducted research it has been found out that the direction and intensity of water and salt regimes in the irrigated land areas of the Ararat valley are related to the ground water levels, mineralization, crops᾿ species composition and to the irrigation factors. Under conditions of high level of ground water (<1.75 m) some salt accumulation is observed in the mid and surface soil strata, which can lead to the decline of soil fertility and crops productivity. Hence, it is recommended to implement irrigation and leaching activities in spring and autumn seasons along the mentioned land areas increasing the irrigation rate in 1.5 times.

Osobine i nivo podzemne vode Humoglej zemljišta južne Bačke

The paper examines hydromorphic soils from the class of gley soils, soil type humogley. The examined soils are located in the protected part of the inundation of the middle course of the Danube. According to the chemical properties of the examined soils, the pH value ranges from 7,64 to 8,15 on average, and with depth there is an increase in alkalinity. The total salts of the examined soils had increased values in the humus horizon and ranged from 0,06 to 0,09%. The texture classes of the humus horizon of these soils are: clay loam to sandy clay loam, while the lower sub-horizons of the gley are textural classes of sandy loam, loamy sand and sand. The influence of the Danube water level on the groundwater level results in high correlation coefficients, which range from 0,67 to 0,88. The groundwater in these soils had the highest level from 28 cm to 70 cm depth, and the lowest level was from 110 to 175 cm deep. The amplitude of groundwater variation during the year in the examined humogley soils ranges from 66 to 132 cm. Groundwater quality classes according to U.S. Salinity Laboratories are unfavorable and range from C3S1 to C4S1, ie salt to very salty water with low sodium content, and according to the FAO classification the water quality is such that there is a moderate need for restriction. High groundwater level above the critical level, as well as watering the soil with water of this quality can have an impact on salinization of the surface horizon of humogley soil of the examined area.

Study on rainfall infiltration in high groundwater channels

In order to solve the adverse effect that the lining of high groundwater level channels is prone to damage when subjected to heavy rainfall, the response law of internal structural state of high groundwater level channels under different rainfall conditions was studied. Based on the non-seepage seepage theory, the seepage pressure (total water head) in the tunnel under four different rainfall types is analyzed and studied. The results show that the most unfavorable rainfall types for the lining structure safety are the frontal rainfall and uniform type rainfall. Therefore we should pay more attention to the front type and uniform type rainfall from the perspective of seepage. The research results can provide reference for slope and seepage control design of high groundwater level channels.

Analysis of Inflow Solutions among Eleven Sewer Systems

This paper was undertaken to compare eleven utilities where part or all of the utility was tested for infiltration and inflow with the intention of determining the value of data gathered from midnight investigations, comparing potential costs (in 2020 dollars), and understanding whether statistical methods can be used to predict potential problems on the system. Inflow and infiltration amounts can be identified on a utility system without significant effort. Inflow correction is robust and easy to implement (though often overlooked). After inflow is addressed, the results indicated that a midnight investigation could quickly identify portions of the sewer system in need of attention. Maps of leaky pipe sections can be identified, and commonalities in the system may become apparent. Statistical methods were used to identify high groundwater levels and lateral issues as critical issues on these systems. The methods can be utilized at other utilities to help guide them to addressing the critical issues first as opposed to focusing only on the traditional pipe lining solutions that often ignore the lateral and inflow issues that plague utility managers.

Analisis Stabilitas Lereng Menggunakan Model Numerik 3 Dimensi Studi Kasus Lereng Sekolah Terpadu di Kecamatan Jonggol Bogor

Slope is the surface of the earth that forms an inclination angle, that it has the potential for landslides. Landslide will be occurred by several factors, such as steep slopes, large loads, high rain intensity, poor drainage systems, high ground water levels and others. Therefore, slope stability analysis is needed to ensured that the slopes are safe from landslides potential which injured many people. As for the prevention and handling of landslides that can be done, such as changing the geometry of the slopes, improving the drainage system, providing slope reinforcement such as gabions, retaining walls, poles and others. This study aims to determine the effect of water level on the stability of the existing slope and which has been reinforced by bored piles using a 3-dimensional numerical model. The case study reviewed is the slope in the Integrated School in Bendungan Village, Jonggol District, Bogor Regency. The results of the analysis show that in the existing conditions with a normal water level, the value of the safety factor (SF) is 1.16, and when the water level is critical, the SF value is 1.14. Whereas in slope conditions with the reinforcement of the bored pile, the analysis results show that the SF value with normal water level is 2.33 and when the water level is critical is 1.58. The results of the analysis with the reinforcement of the drill pile show that the SF value is more than 1.5 so that the slope is safe from landslide based on SNI 8460 of 2017.

Carbon and water balance of an afforested shallow drained peatland in Iceland

Drainage of peatlands increases the depth of the oxic peat layer and can turn them into a carbon (C) source to the atmosphere. Afforestation of drained peatlands could help to reverse this process since the trees may enhance C sequestration. We followed the C and water dynamics of an afforested drained peatland in S-Iceland during a 2 year period, during which the Black Cottonwood (Populus balsamifera ssp. trichocarpa) plantation was 23–25 year old. Net ecosystem exchange (NEE) of carbon dioxide (CO2) was measured with the eddy covariance method and C pools of trees and ground vegetation were measured using the stock change method. Lateral losses of dissolved and particulated organic C (DOC, POC) were estimated from weekly water-runoff samples. Unexpectedly, the afforested drained peatland was a strong sink of carbon during the two years, with an average NEE value of 714 g C m−2 yr−1. Only 0.5% of the total NEE was lost through lateral DOC and POC transport, leaving 710 g C m−2 yr−1 as the total net ecosystem production (NEP). Ca. 91% of the observed NEP could be explained by the annual biomass increment of the Black Cottonwood trees and 1.3% by the ground vegetation. This means that the remaining 7.5% of the total NEP most likely accumulated in peat soil and litter, contributing to the soil C stocks. The dormant-season CO2 emissions were unexpectedly low, which was explained by a high groundwater level at this drained site outside the ca. 5 months of the active growing season. On average, 66% of the annual measured precipitation was estimated to have evaporated back to the atmosphere. This left 416 mm for potential runoff, which was somewhat lower value than the measured runoff (662 mm). These results indicate that during the age span of ca. 20–25 years, afforestation was a valid method to reverse the expected negative C-balance of this drained grassland pasture in Iceland. Although the site is currently a soil C sink, simulation studies with process models are needed to test whether such sites could remain C sinks when managed for forestry over several tree-stand rotations.

Seasonal Variation on the Hydrochemistry and Height of Brackish-Water from Commodore Channel, Lagos, Nigeria

The current study deals with the evaluation of physicochemical characteristics, nutrient status, and variation in the height of surface water from the commodore channel, and its comparison with the hydrochemical characteristics of the monitoring borehole from the NIOMR Jetty, Lagos, Nigeria. We aim to further improve our understanding of the interrelationship of climate change and hydrological cycle, and its impacts in the Lagos coastal environments. The observed ranges of physicochemical characteristics of the surface water are dissolved oxygen (DO) 3.07-6.05mg/L; pH: 7.99-8.48; temperature 26.97-30.34°C, electrical conductivity (EC) 9680-47800mS/cm; salinity (Sal) 6.51-28.05‰ and water level 1.24-1.79m. The concentration of nutrient range from nitrite 10-36mg/l, nitrate 28-44mg/l, sulphate 38-90mg/l and phosphate 2-78mg/l. The analyzed hydrochemical characteristics from all the stations are within the desired values for healthy marine ecosystems when compared with Federal Ministry of Environment (FMENV) Nigeria permissible limits which are: DO >5 mg/l, pH 6.5-9, temperature <40°C, nitrite 1mg/l, nitrate 20mg/l, phosphate 5mg/l and sulphate 500mg/l; except low DO (<4.5mg/l) in January, November and December, and elevated nitrite, nitrate and phosphate values across the season. The low DO values may be attributed to enhanced transportation of non-biodegradable organic loads that utilize the available DO for chemical oxidation and microbial decomposition. While the enriched nitrite, nitrate and phosphate concentrations suggest enhanced productivity and influx of nutrients rich flood water from the anthropogenic source. Our study showed a coincidence in the highest brackish water height of the surface water (1.24m) from the commodore channel with the highest groundwater level (1.58m) in October. The lowest height of water levels was recorded in February and March at 2.23m and 1.79m for groundwater and surface water respectively. The similarities in the height of water levels were recorded with contrasting hydrochemical variables (e.g., high Ec vs. low Ec; and high Sal vs. low Sal), which confirmed the effect of rainfall/freshwater incursion on the surface water and simultaneous occurrence of subsurface pollution arising from seawater intrusion on the groundwater samples in October. This study had shown that a long term monitoring of rise in water levels and hydrochemical variables of surface and groundwater can be used to understand climate change and early warning predictions of flooding in coastal environments.

Characterising hillslope–stream connectivity with a joint event analysis of stream and groundwater levels

Abstract. Hillslope–stream connectivity controls runoff generation, during events and during baseflow conditions. However, assessing subsurface connectivity is a challenging task, as it occurs in the hidden subsurface domain where water flow can not be easily observed. We therefore investigated if the results of a joint analysis of rainfall event responses of near-stream groundwater levels and stream water levels could serve as a viable proxy for hillslope–stream connectivity. The analysis focuses on the extent of response, correlations, lag times and synchronicity. As a first step, a new data analysis scheme was developed, separating the aspects of (a) response timing and (b) extent of water level change. This provides new perspectives on the relationship between groundwater and stream responses. In a second step we investigated if this analysis can give an indication of hillslope–stream connectivity at the catchment scale. Stream water levels and groundwater levels were measured at five different hillslopes over 5 to 6 years. Using a new detection algorithm, we extracted 706 rainfall response events for subsequent analysis. Carrying out this analysis in two different geological regions (schist and marls) allowed us to test the usefulness of the proxy under different hydrological settings while also providing insight into the geologically driven differences in response behaviour. For rainfall events with low initial groundwater level, groundwater level responses often lag behind the stream with respect to the start of rise and the time of peak. This lag disappears at high antecedent groundwater levels. At low groundwater levels the relationship between groundwater and stream water level responses to rainfall are highly variable, while at high groundwater levels, above a certain threshold, this relationship tends to become more uniform. The same threshold was able to predict increased likelihood for high runoff coefficients, indicating a strong increase in connectivity once the groundwater level threshold was surpassed. The joint analysis of shallow near-stream groundwater and stream water levels provided information on the presence or absence and to a certain extent also on the degree of subsurface hillslope–stream connectivity. The underlying threshold processes were interpreted as transmissivity feedback in the marls and fill-and-spill in the schist. The value of these measurements is high; however, time series of several years and a large number of events are necessary to produce representative results. We also find that locally measured thresholds in groundwater levels can provide insight into the connectivity and event response of the corresponding headwater catchments. If the location of the well is chosen wisely, a single time series of shallow groundwater can indicate if the catchment is in a state of high or low connectivity.

Non-firing materials using clay soils

This paper is concerned with the creation of non-firing technologies for strengthening clay soils in places with high groundwater level. The procedure for predicting the properties of composites by the activity of the surface of the fillers, carried out using modern diagnostic methods developed by the authors, has shown the effectiveness of its application on construction sites in the Voronezh region when building road bases and strengthening soils for buildings and structures. Using the defrosting effect on the construction site allows one to extend the seasonality of work on roads and construction sites and improve the quality of soil preparation due to the increased dispersion of unfrozen clay. The increase in the deformation modulus and strength of soil foundations was measured to be 2–3 times, as well as the decrease in porosity and the increase in soil density by 1.25 times, the decrease in moisture concentration over time due to the ability of the slag block to absorb moisture from the soil for a long time. Strengthening the soil by the broken stone materials formed during the demolition of buildings and structures allows one to create reliable homogeneous soil bases at construction sites in difficult hydrogeological conditions.

Liquefaction Analysis Based on Liquefaction Potential Index Method in Prambanan Temple Complex of Jogjakarta

Prambanan Temple is a cultural heritage located in Jogjakarta. Tectonically, the Special Region of Jogjakarta and its surroundings are an area with a fairly high level of seismic activity in Indonesia. Geotechnically, the soil in Jogjakarta is sandy with similar gradation. The thickness of the sand ranges from -50 m to -60 m. Whereas, the ground water level is located at a depth of -12 m during dry season and in rainy season, it rises from -6 m to -4 m. The impact of soil types and the high Ground Water Level (GWL) allow it for liquidation to occur during an earthquake. This study was conducted using liquefaction analysis, through Liquefaction Potential Index (LPI) method with ground water level variations. Before analyzing the liquefaction using LPI method, Peak Ground Acceleration (PGA) methods were used, and analysis could then be done through Cyclic Resistance Ratio (CRR) and Cyclic Stress Ratio (CSR) to obtain safety factors and the Liquefaction Potential Index analysis was then conducted. To analyze this liquefaction, earthquake data from 2004 to 2019 and the results of the SPT field test at the Prambanan Temple were needed. From the liquefaction potential analysis through Liquefaction Potential Index (LPI), the results showed that in CSR Seed & Idriss (1971) and CRR Tokimatsu & Yoshimi (1983), GWL 1 m at depths from 4.5 m and above, the potential of liquefaction occurrence was high. The largest PGA value was obtained based on the Matsuchka (1980) method on May 26, 2006 which was 0.102.

Higher groundwater levels in western Europe characterize warm periods in the Common Era

Hydroclimate, the interplay of moisture supply and evaporative demand, is essential for ecological and agricultural systems. The understanding of long-term hydroclimate changes is, however, limited because instrumental measurements are inadequate in length to capture the full range of precipitation and temperature variability and by the uneven distribution of high-resolution proxy records in space and time. Here, we present a tree-ring-based reconstruction of interannual to centennial-scale groundwater level (GWL) fluctuations for south-western Germany and north-eastern France. Continuously covering the period of 265–2017 CE, our new record from the Upper Rhine Valley shows that the warm periods during late Roman, medieval and recent times were characterized by higher GWLs. Lower GWLs were found during the cold periods of the Late Antique Little Ice Age (LALIA; 536 to ~ 660 CE) and the Little Ice Age (LIA; between medieval and recent warming). The reconstructed GWL fluctuations are in agreement with multidecadal North Atlantic climate variability derived from independent proxies. Warm and wet hydroclimate conditions are found during warm states of the Atlantic Ocean and positive phases of the North Atlantic Oscillation on decadal scales.