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Large-scale spatial interpolation of soil pH across the Loess Plateau, China
Springer Science and Business Media LLC - Tập 69 - Trang 2731-2741 - 2012
Soil pH plays an important role in biogeochemical processes in soils. The spatial distribution of soil pH provides basic and useful information relevant to soil management and agricultural production. To obtain an accurate distribution map of soil pH on the Loess Plateau of China, 382 sampling sites were investigated throughout the region and four interpolation methods, i.e., inverse distance weighting (IDW), splines, ordinary kriging, and cokriging, were applied to produce a continuous soil pH surface. In the study region, soil pH values ranged from 6.06 to 10.76, with a mean of 8.49 and a median of 8.48. Land use type had a significant effect (p < 0.01) on soil pH; grassland soils had higher pHs than cropland and forestland soils. From a regional perspective, soil pH showed weak variation and strong spatial dependence, indicated by the low values of the coefficient of variation (0.05) and the nugget-to-sill ratios (<0.25). Indices of cross-validation, i.e., average error, mean absolute error, root mean square error, and model efficiency coefficient were used to compare the performance of the four different interpolation methods. Kriging methods interpolated more accurately than IDW and splines. Cokriging performed better than ordinary kriging and the accuracy was improved using soil organic carbon as an auxiliary variable. Regional distribution maps of soil pH were produced. The southeastern part of the region had relatively low soil pH values, probably due to higher precipitation, leaching, and higher soil organic matter contents. Areas of high soil pH were located in the north of the central part of the region, possibly associated with the salinization of sandy soils under inappropriate irrigation practices in an arid climate. Map accuracy could be further improved using new methods and incorporating other auxiliary variables, such as precipitation, elevation, terrain attributes, and vegetation types.
Delineation of groundwater potential zones and recommendation of artificial recharge structures for augmentation of groundwater resources in Vattamalaikarai Basin, South India
Springer Science and Business Media LLC - Tập 79 - Trang 1-13 - 2020
Nowadays, GIS and remote sensing techniques are effectively used to find groundwater prospect zones in various troublesome landscapes throughout the world. In the present work, groundwater potential zonation mapping was carried out for the Vattamalaikarai River basin in South India by overlaying ten thematic maps such as soil, drainage density, lineament density, geology, slope, land use/land cover, geomorphology, topographic position index, rainfall and groundwater level by giving appropriate weightages to each significant parameter with respect to its influence on groundwater. As the basin mainly depends on the groundwater resources, it is necessary to assess the groundwater prospect for the better management of aquifer system. Groundwater potential zonation map illustrates that more than 50% of the basin region falls under moderate to low groundwater potential category. Highly influential thematic layers were integrated to generate groundwater recharge zonation map. Based on this output, artificial recharge sites were selected to replenish the groundwater resources in the basin. Three check dam sites were suggested across the third- and fourth-order streams. Four suitable sites for the construction of percolation ponds and ten locations for the construction of recharge pits were also identified. Four injection well sites were recommended to augment groundwater in the aquifer present under the black cotton soil regions in the western part of the basin.
Soil water transport and plant water use patterns in subsidence fracture zone due to coal mining using isotopic labeling
Springer Science and Business Media LLC - Tập 81 - Trang 1-8 - 2022
With more underground coal mining, soil subsidence and fracture have increasingly developed and resulted in changed hydrological progress; however, the effects of subsidence fracture on plant water uptake patterns remain largely unknown. This study aimed at investigating whether there were variations in soil water transport and plant water use patterns in subsidence fracture zone and fracture-free zone compared to the non-mining areas. The isotopically labeled water (2H) injection experiments were conducted and the MixSIAR model was used to explore the mechanism of soil water infiltration and water sources of Artemisia Desertorum in a semi-arid coal-mining area. The results showed that: (1) the proportion of the preferential flow in the subsidence fracture zone from the water balance equation was 18.2%; (2) in non-mining zone, 59.7% of water used by Artemisia Desertorum was from the 10–20 cm soil profile layer; (3) in the fracture-free zone, 46.6% and 39.4% of water were from the 40–60 cm and 0–10 cm layers, respectively; and (4) in the subsidence fracture zone, 85.9% of water derived mainly from the 40–60 cm layer. This study provided new insights into soil water transport and plant water uptake patterns in the subsidence fracture zone of coal-mining areas.
Estimation of surface soil water content from surface temperatures in dust source regions of Mongolia and China
Springer Science and Business Media LLC - Tập 65 - Trang 1847-1853 - 2011
Surface conditions, such as surface roughness and soil moisture, control wind erosion and dust emission in northeast Asia. Data on spatial and temporal changes of surface soil water content are needed for dust-modeling systems used to predict dust events with the aim of preventing damage from them. A modified temperature-vegetation dryness index (MTVDI) was tested to see if it could reproduce surface soil water contents measured during the dust event season in Bayan Unjuul, Mongolia, and Shenmu, China. MTVDI was calculated from land surface temperature and aerodynamic minimum and maximum surface temperatures estimated from meteorological data. The standard deviation of the error of estimations of soil water content from MTVDI was ±1.5% in Bayan Unjuul when soil water content was lower than 4%. This compares favorably with the observational error of ±1% of the soil moisture sensors used.
Pollution assessment of arsenic and other selected elements in the groundwater and soil of the Gulf of Aqaba, Saudi Arabia
Springer Science and Business Media LLC - Tập 75 - Trang 1-10 - 2016
Forty-six soil and groundwater samples were collected from the agricultural farms of the Gulf of Aqaba coast. Additionally, 24 granitic and marine sedimentary rock samples were collected from the study area. The collected samples were analyzed for As, Al, Au, B, Ba, Be, Fe, Sb, Se, Sn, Ti, and V using inductively coupled plasma mass spectrometry. Levels of the studied metals in the groundwater samples lie within the acceptable limits of the World Health Organization (WHO). The rock samples exhibit a significant variation in mean metal content from one rock type to another. Concentrations of As and B in the soil samples were determined to be higher than those of Canadian Soil Quality Guidelines (CSQG) and were primarily due to agricultural and seawater inputs. Chemical weathering of various rock units also plays a significant role. The calculations of geoaccumulation index are found to be more reliable than of those of enrichment factor for Arsenic contamination levels assessment. The study area is not significantly affected by As contamination. The correlation coefficient analysis results for the soil and groundwater data reveal a variable degree of correlations between As and other metals in the study area.
Bat algorithm for dam–reservoir operation
Springer Science and Business Media LLC - Tập 77 Số 13 - 2018
A laboratory study of the pollution of formaldehyde in cemeteries (South Africa)
Springer Science and Business Media LLC - Tập 77 - Trang 1-10 - 2018
Cemeteries are known to be associated with soil and groundwater pollution from contaminants in coffin materials. However, possible contamination from embalming fluids such as formaldehyde has not been investigated. Formaldehyde is a recognised carcinogen, which is primarily toxic after inhalation, skin contact or ingestion. Although it is maintained that formaldehyde breaks down into innocuous compounds, this has not been established at sites such as cemeteries where there is a continuous addition of formaldehyde-preserved bodies, sometimes on a daily basis. It is also not confirmed whether different soil types and environmental conditions affect the leaching of formaldehyde into groundwater resources. This study comprises a laboratory study of the leaching potential of formaldehyde through different soils and environmental conditions. Twenty-seven containers with taps were filled with either sandy, silty or clayey soils. Samples of burial materials and a cloth saturated with formalin were buried within each column. These were exposed to conditions simulating that of the environment, i.e. (1) different temperatures, (2) heavy or prolonged rainfall and (3) using either acidic or slightly acid water. Leachate samples were collected every 2 weeks for a period of 24 weeks and analysed for formaldehyde using acid titration. The results showed that most formaldehyde percolated through the soil between week 6 and week 14 of interment, with a greater amount being leached from sand. Neither temperature nor pH affected the amount of formaldehyde leached; however, conditions simulating heavy rainfall facilitated leaching. Although a total of only 3% of the initial amount of formaldehyde mobilised, concentrations of up to 15 mg/L formaldehyde were recorded on two occasions, exceeding the tolerable concentration recommended by the World Health Organisation.
Land use changes and impact on coral communities along the central Pacific coast of Mexico
Springer Science and Business Media LLC - Tập 65 - Trang 1095-1104 - 2011
The loss of coral coverage from environmental degradation is a progressive phenomenon that occurs in coral communities around the world. However, the consequences of land use changes and its impact on the state of conservation of coral communities are not yet understood. This study compares the impact of coastal land use changes on four coral communities near rural (Isla Faro and El Zapote) and suburban (Caleta de Chon and Playa Manzanillo) sites in the states of Michoacan and Guerrero, along the central Pacific coast of Mexico. Indicators of environmental degradation in coral communities (sediment deposition, water transparency, total suspended solids, and chlorophyll concentration) show that signs of eutrophication are absent from both rural sites in Michoacan. This absence suggests that human impact is not the main cause of the observed degradation (coral Mortality Index MI = 0.85, a high death coral coverage ~42% and the lowest species richness). Instead, the 1997–1998 El Niño-Southern Oscillation (ENSO) event (the strongest in the last decade) appears to be the major factor in this coral cover decline, as it occurred in the eastern Pacific and other regions of the world. In contrast, coral communities near the suburban sites in Guerrero are well developed, and their coral coverage and species richness (up to 67.7% and 7 species, respectively) are comparable to other major coral communities in this region. Nonetheless, indicators of human-derived degradation in the Guerrero coastal zone near Caleta de Chon and Playa Manzanillo, including high sediment deposition up to 1.2 kg m−2 d−1, low water transparency <5 m, presence of filamentous algae on dead corals and a coral Mortality Index of MI ~0.6 show that human impact is beginning to affect the conservation state of these coral communities, reducing their species richness and coral coverage. Although the ENSO impact on coral communities could be more drastic than the anthropogenic impact, the current study confirms that increased land use changes and coastal erosion are causing progressive coral community degradation. Therefore, land and coastal changes must be rigorously regulated.
Three step-drawdown dewatering test in unsteady flow condition: a case study of the Siwan coal mine in North China Coalfield
Springer Science and Business Media LLC - Tập 77 - Trang 1-11 - 2018
A dewatering test is a common tool to estimate the physical properties of water-bearing layers in coal mines. The three step-drawdown dewatering test of unsteady flow, which combines both steady and unsteady flows, is designed in this study. The test design involves the identification of hydrogeological conditions, calculation of hydrogeological parameters, and prediction of mine water yields, particularly those of the Siwan coal mine in the coal mining district of Hebi. The results show that the water storage and the abundance of the second limestone aquifer in Taiyuan formation (L2) is limited and easy to drain, while the Ordovician system aquifer (O2) lateral recharges the L2 by the F8 fault. The correlation curve method, the cone balance method, and the analytical method are conducted in this study. Results show that the average water yield was 1436.1 m3/h when the water level of L2 decreased from + 127 m to + 17 m. The three step-drawdown dewatering test not only provides ways to enrich the experimental data and reveal hydrogeological conditions, but it can also be adopted in several approaches to predict mine water yields.
Prehistoric and recent mass movements of the World Cultural Heritage Site Hallstatt, Austria
Springer Science and Business Media LLC - Tập 47 - Trang 702-714 - 2005
Hallstatt Village, located in the Austrian Alps, is designated by the United Nations Educational, Scientific and Cultural Organization as part of the World Cultural Heritage Site “Hallstatt–Dachstein”. This region is recognized for its salt deposits that have been exploited since the Neolithic period. In former times, these salt deposits were very rare and precious. Due to unfortunate bedding conditions, mass movements have been frequent in the past and continue to affect the site today. These active and inactive mass movements were mapped geotechnically to a scale of 1:5,000 and the mineralogical and mechanical properties of the main instable soft rocks were investigated. Rock spreads, rock slides, rock falls, rock topples, earth flows and earth and debris slides are the primary types of mass movements recorded. They are most frequently observed in areas affected by mining, though they may also occur in areas where no anthropogenic influence is recognized. Evidence exists in the archaeological record that indicates prehistoric mining activities were also seriously affected by the impact of mass movements.
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