It is important to know the quality of water resources for drinking, domestic and irrigation in the rural area. Because, in recent times, there has been increased demand for water due to population ...growth and intense agricultural activities, so, hydrogeochemical investigations come into prominence for the groundwater use. The purpose of this paper is to evaluate water quality of Başköy springs for both drinking and irrigation purposes. The geochemical processes and quality of springs were followed as seasonal in the study area. In view of geochemical classification, springs are Ca-Mg-HCO
3
water type for both seasons. Comparison of geochemical data shows that majority of the spring samples are suitable for drinking water. On the other hand, chemical indexes of springs with various classifications were calculated for irrigation purposes. According to the classifications (electrical conductivity, total dissolved solids, total hardness, salinity hazard, percent sodium, sodium adsorption ratio, residual sodium carbonate, residual sodium bicarbonate, permeability index, potential salinity, soluble sodium percentage, magnesium ratio, and Kelly’s ratio), Başköy springs are suitable for irrigation purposes. However, water quality of Çaygözü spring is different the other springs due to the high electrical conductivity and total dissolved solids. Also, groundwater mineralization processes and rock–water interaction are controlled with bivariate diagrams of major elements.
Groundwater is one of the most valuable natural resources in the world (Jha et al., 2007). However, it is not an unlimited resource; therefore understanding groundwater potential is crucial to ensure ...its sustainable use. The aim of the current study is to propose and verify new artificial intelligence methods for the spatial prediction of groundwater spring potential mapping at the Koohdasht–Nourabad plain, Lorestan province, Iran. These methods are new hybrids of an adaptive neuro-fuzzy inference system (ANFIS) and five metaheuristic algorithms, namely invasive weed optimization (IWO), differential evolution (DE), firefly algorithm (FA), particle swarm optimization (PSO), and the bees algorithm (BA). A total of 2463 spring locations were identified and collected, and then divided randomly into two subsets: 70 % (1725 locations) were used for training models and the remaining 30 % (738 spring locations) were utilized for evaluating the models. A total of 13 groundwater conditioning factors were prepared for modeling, namely the slope degree, slope aspect, altitude, plan curvature, stream power index (SPI), topographic wetness index (TWI), terrain roughness index (TRI), distance from fault, distance from river, land use/land cover, rainfall, soil order, and lithology. In the next step, the step-wise assessment ratio analysis (SWARA) method was applied to quantify the degree of relevance of these groundwater conditioning factors. The global performance of these derived models was assessed using the area under the curve (AUC). In addition, the Friedman and Wilcoxon signed-rank tests were carried out to check and confirm the best model to use in this study. The result showed that all models have a high prediction performance; however, the ANFIS–DE model has the highest prediction capability (AUC = 0.875), followed by the ANFIS–IWO model, the ANFIS–FA model (0.873), the ANFIS–PSO model (0.865), and the ANFIS–BA model (0.839). The results of this research can be useful for decision makers responsible for the sustainable management of groundwater resources.
The role of travertine fissure-ridges in reconstructing tectonics and related earthquakes is a challenging issue of recent debate directed at delineating historical/prehistorical seismic records. ...Indeed, direct measurements on a travertine fissure-ridge immediately after a seismic event have never been previously performed. We describe the co- and post-seismic effects of a M = 3.6 earthquake on fluid flow and travertine deposition in a geothermal area of Tuscany (Italy). Direct observation allows us to demonstrate that thermal spring (re)activation is directly influenced by transient seismic waves, therefore providing a basis for reconstructing seismic events in the past.
Travertines are generally considered as carbonate deposits related to Ca-rich hot springs. Ca-deficiency hot springs, however, can also produce travertines under suitable conditions and little is ...known about the travertine deposition and diagenesis in these systems. Therefore, we studied a fossil perched Ca-deficiency spring system at Shihuadong, China to discuss its genesis and diagenesis. This system is a platform-like build-up with travertines developing mainly in the steep frontal area. The travertines were deposited from high-temperature fluids (dominantly 45 °C to 55 °C) with strong interaction mostly with underground Gaoligong Group metamorphic rocks. Their parent CO2 was originated from magmatic CO2 and a little soil CO2. The travertine-depositing paleofluid was predominantly Ca-deficiency hot spring water, but stream water possibly from cold springs on surrounding hills might make a small contribution. The low calcium levels and flat substrate on the top area of the studied system handicapped the travertine deposition, only developing a small perched travertine channel entirely composed of crystalline crust. On the contrary, progressive CO2 degassing in the top area and increasing CO2 degassing and water flow rates in the frontal area induced the formation of abundant travertines. However, water scattering/dispersion in the frontal area might not heavily increase the water flow rate and only induced boundstone deposition. After the travertine deposition, underground thermal water, meteoric water, and microbial activity progressively altered the primary fabrics, forming mosaic and need fiber calcite cements, dissolution pores, microborings, and dissolution-induced and microbe-induced micritization. The studied perched spring system shows limited scales, notable progradation but slight aggradation, and the dearth of distal autochthonous travertines, unlike those formed by Ca-rich hot springs, which might extend widely and produce striking distal travertine deposits away from the frontal slope/waterfall. These findings suggest the significant roles of water chemistry and local topography in travertine deposition and the influence of slowly underground thermal water seeping on the diagenesis of travertines in hilly areas and might be used to recognize fossil Ca-deficiency and Ca-rich hot spring systems.
Elevated nitrate concentrations in groundwater are a common challenge for water management. One important factor in this context is higher frequencies and intensities of wet‐dry cycles that may cause ...increased nitrate concentrations in groundwater due to nitrate flushes after drought termination. Yet systematic studies on regional‐scale impacts of droughts on groundwater nitrate concentrations are missing so far. Here we analyzed time series of 44 shallow groundwater wells and 41 springs all across the German Federal State Baden‐Wuerttemberg from 2000 to 2018 to characterize patterns of post‐drought nitrate increase in groundwater. In general, half of the exceptional nitrate concentrations, which exceeded the 80th percentile of long‐term nitrate measurements, could be related to droughts in the research timeframe. The 2003 drought event stood out in terms of drought severity and post‐drought nitrate concentration increases in our data. The great majority (91%) of all monitoring sites showed at least one exceptionally high nitrate concentration in the 4 years following the 2003 drought event. Springs were mainly located in forests of steep low mountain ranges and wells in cropland of flat river valleys. Therefore, delay times between drought intensity and nitrate concentration increases as well as magnitudes of nitrate concentration increase were diverse among wells and springs. We derived two distinct nitrate response patterns: (i) nitrate increases immediately following drought events (more common for springs and fractured rock aquifers) and (ii) delayed nitrate increases (more common for wells and porous aquifers). Springs generally showed quicker (median of 101 days) but weaker (median of +1.3 mg/L) post‐drought nitrate increases than wells (185 days, +3.4 mg/L). Only few sites exhibited no post‐drought nitrate increase and post‐drought mean‐nitrate concentrations of groundwater reservoirs were extraordinarily high in 2006. Overall, we demonstrate that post‐drought nitrate increase in groundwater is omnipresent, while different landscapes and hydrogeological characteristics create a diverse regional pattern. As severe droughts become more frequent in a changing climate, post‐drought nitrate increase may intensify problems regarding water quality and supply.
Analyzing data from 41 springs and 44 groundwater wells in southwest Germany we found that 91% of all monitoring sites showed at least one exceptionally high nitrate concentration as a response to the 2003 drought event. Springs generally showed quicker (median of 101 days) but weaker (median of +1.3 mg/L) reactions than groundwater wells (185 days, +3.4 mg/L). Overall, we demonstrate that post‐drought nitrate increase in groundwater is omnipresent, while different landscapes and hydrogeological characteristics create a diverse regional pattern.
The Asian-Pacific - continental margins have been the object of intensive geochemical research in recent years, as areas within this zone have been found to contain large hydrocarbon deposits in a ...variety of forms including: oil, natural gas, gas condensate, and gas hydrates. One such area is Sakhalin Island, located in Russia's Far Eastern Federal District. Genetically, the territory of Sakhalin Island is a part of the shelf of the Hokkaido-Sakhalin fold area, therefore, the nature of the sub-vertical gas migration is controlled by deep faults, along which the concentrations of natural gases change, and is also influenced by high seismotectonic activity of the Okhotsk region. This paper presents data regarding the distribution of helium, hydrogen, carbon dioxide and methane from mud volcanoes, thermal springs, mineral waters and other seep types on Sakhalin island and the surrounding marine margins, along with an interpretation of the geological and tectonic factors that have likely led to the present distribution of these gases. In general, the results of geothermometry equations based on the concentration and stable isotopic composition of carbon dioxide indicate much higher temperatures than equations involving the saturation concentrations of hydrogen gas. We interpret this to indicate that deeply-sourced carbon dioxide does not reequilibrate at near-surface conditions, whereas the equilibration time for hydrogen gas is relatively rapid. Areas on the island which are observed to have active degassing, coupled with high apparent reservoir temperatures also provide indicators of geodynamics along the regional tectonic structures. Mud volcanoes to the south of the island are predominantly situated at the juncture between NW-SE trending faults which extend the entire length of Sakhalin and continue as far south as Hokkaido Island, and more recently developed NE-SW trending faults. Despite the relatively low water temperatures of these mud volcanoes, the high reservoir temperatures indicated by gas chemistry suggest a source of fluids and gas at several km from the surface.
•Distribution of helium, hydrogen, carbon dioxide and methane on Sakhalin Island and the surrounding marine margins.•Geological and tectonic factors leading to helium, hydrogen, carbon dioxide and methane distribution on Sakhalin Island.•Areas of active degassing present high apparent reservoir temperatures as a consequence of regional tectonic structures.•The high reservoir temperatures in Sakhalin mud volcanoes suggest a source several km from the surface.
Spring water is a reliable source of potable water to many communities and habitants in western Himalayan region of India. The present study evaluates the hydrochemical nature of spring water using ...various drinking parameters and agricultural indices in upper Beas basin of Kullu Valley, Himachal Pradesh, India. Fifty springs were sampled for the estimation of physico-chemical parameters and major ions. The results indicate that majority of the spring waters in the study area are suitable for drinking as well as irrigation purposes except for few locations. About 14% of springs showed high nitrate content (45 to 92.6 mg/L) more than BIS permissible limit of 45 mg/L. The source of contamination could be sewage disposal, livestock waste and fertilizers. Fluoride (0.16–0.49 mg/L) was found to be within permissible limits for drinking. Drinking Water Quality Index ranges from 1.74 to 108, and Irrigation Water Quality Index ranges from 0.27 to 8.21. Both these indices indicate that the spring water falls in excellent to good category and is suitable in terms of potability and irrigation uses. Hydrogeochemical characteristics of the spring waters indicate that alkaline earths (Ca
2+
+ Mg
2+
) dominate alkalies (Na
+
+ K
+
) and strong acids (SO
4
2−
+ Cl
−
) dominate weak acids (CO
3
2−
+ HCO
3
−
). Based on Piper’s classification, the spring water data falls in no cation–no anion dominant zone followed by carbonate hardness (secondary alkalinity) zone and hydrochemical trends (Piper’s and Gibb’s plots) inferred that spring water chemistry is mainly controlled by water rock interaction followed by rainwater chemistry.
Abstract The results of a study of the mechanical characteristics of the BrNHK bronze alloy using the acoustic emission method are presented. The mechanical characteristics of BrNHK-2.5-0.6-0.7 wire ...were studied after various heat treatment modes. The widespread use of bronze alloy BrKMts3-1 is due to its low price, while the mechanical and operational properties satisfy both consumers and spring manufacturers, since the technology for manufacturing springs from this alloy is not fundamentally different from the technology for manufacturing springs from cold-worked wire. In turn, the BrB2 alloy is considered a scarce alloy and is used only for springs intended for special equipment, since the properties of this alloy after hardening heat treatment are not inferior to cold-worked carbon steels. Given the increased cost of beryllium, work is underway both to reduce the beryllium content and to switch to beryllium-free alloys.
The origin(s) of dissimilatory sulfate and/or (bi)sulfite reducing organisms (SRO) remains enigmatic despite their importance in global carbon and sulfur cycling since at least 3.4 Ga. Here, we ...describe novel, deep-branching archaeal SRO populations distantly related to other Diaforarchaea from two moderately acidic thermal springs. Dissimilatory (bi)sulfite reductase homologs, DsrABC, encoded in metagenome assembled genomes (MAGs) from spring sediments comprise one of the earliest evolving Dsr lineages. DsrA homologs were expressed in situ under moderately acidic conditions. MAGs lacked genes encoding proteins that activate sulfate prior to (bi)sulfite reduction. This is consistent with sulfide production in enrichment cultures provided sulfite but not sulfate. We suggest input of volcanic sulfur dioxide to anoxic spring-water yields (bi)sulfite and moderately acidic conditions that favor its stability and bioavailability. The presence of similar volcanic springs at the time SRO are thought to have originated (>3.4 Ga) may have supplied (bi)sulfite that supported ancestral SRO. These observations coincide with the lack of inferred SO
reduction capacity in nearly all organisms with early-branching DsrAB and which are near universally found in hydrothermal environments.
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