Search

This domain is an integral part of the wider sub-theme directed to site description. It relates to the characterization or confirmation of surface ecosystem properties at the present day, but also to the obtaining and applying of data relevant to making projections of the potential evolution of surface ecosystem properties in the future. Thus, although the focus is on characterization, the information and approaches adopted are closely related to assessing how future climate change and landscape development would affect surface ecosystem properties., Reviewer: Elena ABARCA (Amphos 21)

This preprint is submitted to the JCC Universitas Negeri Semarang 2017---In most Asia countries, the riverbank area are mostly inhabited by the low-income population, due to the shortage of formal housing. Most of the settlement areas are not equipped with proper sanitation system. Hence, the water quality gets lower overtime with the increasing number of inhabitants around the riverbank. This gets worse with the close hydrological connection between surface water and the shallow groundwater. We compare the state of water quality based on our three case studies: Cikapundung Bandung, Kanal Banjir Timur Semarang, and Cisadane Tangerang. In each location, we gathered the following data: water level measurements, water flow mapping, and water quality samples. Then we make maps to evaluate existing status. The comparison will be done based on the physical and chemical properties that we get from the field. On all locations, we find a very close interactions between surface water and groundwater. The hydrological connections are different in direction from upstream to downstream: gaining stream, combined stream or perched stream, and losing stream. However different river gradient gives a slightly different length of hydrological zonations. All samples show a high bicarbonate from rain water, the dissolution of carbonate minerals from the rocks and soils, and also organic species from microbial activities, which induced by domestic wastes. However we need to make a carbonate balance calculation to breakdown the components. All samples also have high nitrate and nitrite concentration which come from domestic waste along the river and fertilizer from the rice fields upstream (only in Cikapundung river). For further research, we suggest chemical modeling to break up the contamination components and possible sources.

The Edwards Aquifer (EA) in Central Texas provides water supply for over two million people and contains springs that are hydrologically and ecologically important to the region. The residence time of groundwater in the EA ranges from a few days to many thousands of years, since water in the aquifer is contained and transported within both matrix porosity and large conduits. In this study, stable isotopes of water from five springs are investigated for tracing the origin of water and hydrological processes in the EA system during 2017–2019. There is a quick response of the isotopic signals measured at these springs to changes in the isotopic compositions of precipitation. By utilizing an isotope mixing model, we have identified sources of water for these springs with a bi-modal distribution of groundwater supply in the EA: water supplied from deep groundwater with a longer residence time (an average of 67%) and supplemental epikarst interflow with a shorter residence time (an average of 33%). The evolution of hydrochemical water types from HCO3–Ca to HCO3·Cl–Ca·Mg along the EA flowpaths indicates that inputs from epikarst interflow are greater in springs within the artesian zone than the springs within the contributing zone. HIGHLIGHTS Stable isotope tracers were utilized to understand the origins of spring water and hydrological processes in the Edwards Aquifer.; There is a quick response for isotopic signals in spring water to changes in the isotopic compositions of precipitation.; There is elevated input from epikarst interflow for spring water balance in the artesian zone than the contributing zone.

This study was performed to evaluate the spatial and temporal distribution of major ions in water samples of a newly designated Ramsar site, namely Kabar Tal (KT) wetland of Bihar. Samples were collected during summer, monsoon, and winter seasons. The analytical and GIS results show that concentration of electrical conductivity, chloride, and nitrate are higher in summer than monsoon and winter. However, the concentration of major cations such as sodium, potassium, calcium, and magnesium are higher in winter than monsoon and summer. In addition, major anions like sulphate and phosphate concentration is higher during monsoon than summer and winter. Multivariate statistical tool (discriminant analysis) results suggest that temperature, pH, electrical conductivity, sulphate, and potassium are the major parameters distinguishing the water quality in different seasons. The study confirms that seasonal variations are playing a major role in the hydrochemistry of KT wetland. Overall, this work outlines the approach towards proper conservation and utilization of wetlands and to assess the quality of surface water for determining its suitability for agricultural purposes. Overall, this work highlights the approach towards estimating the seasonal dynamics of chemical species in KT wetland and its suitability for irrigation purposes. HIGHLIGHTS Spatiotemporal assessment of surface water has been characterized through hydro-chemical studies.; Temperature, pH, EC, sulphate, and potassium, influences water chemistry.; Hydrochemical facies of surface water is of Ca2+ and Cl−; Ca2+- Mg2+ -SO42− and Cl− type.; The surface water of the wetland is of good quality for irrigation.; Detailed exploration for the water chemistry has been studied through statistical methods.

Le Cauron et le Caramy sont les cours d'eau de la partie nord-est du massif karstique de la Sainte-Baume, la plus arrosée. La Grande Foux de Nans-les-Pins est la source principale du Cauron, cours d'eau temporaire en aval. Cette exsurgence épisodique a suscité de nombreuses recherches spéléologiques et techniques dans son réseau noyé, en vue du captage (station de pompage). Elles ont donné des informations sur les variations de niveau de la nappe dans les dolomies karstifiées. Le Caramy, issu à Mazaugues du massif dolomitique de l'Agnis, est réalimenté, particulièrement en été, par la source vauclusienne de la Figuière et les autres exsurgences à l'aval de son canyon. Ce sont des fonctionnements hydrologiques complexes, où interfèrent données naturelles et impacts anthropiques, qui ont posé bien des problèmes pour l'utilisation de leurs eaux. Le massif de la Sainte-Baume joue le rôle d'un réservoir soumis aux conditions climatiques, aux fonctionnements hydrologiques et, de plus en plus, aux modalités d'exploitation, marquées par l'accroissement des prélèvements estivaux, avec le problème des séquences d'années sèches à faible recharge hivernale. The upper basins of the Cauron and Caramy rivers, in the north-eastern part of the Sainte-Baume massif (Var Department, Provence Region): a compound karstic hydrosystems. These rivers proceed from the karstic springs, in the mountainous area with the most important precipitations. The "Grande Foux" (Great Fountain) of Nans-les-Pins, is a vauclusian exsurgence and the main spring of the Cauron, a downstream temporary river. This great temporary exsurgence has been investigated, in the partly flooded network, by numerous speleological and geotechnical researches, for equiped its catchment (with pumping station). These researches have given many data up the running of the aquifer in the karstic dolomites. The Caramy's river, issued in Mazaugues from the dolomitic massif of Agnis, is feeded downstream in its canyon, particularly in summer low-water, by the vauclusian Figuière spring and two other exsurgences. These hydrological researches show a complex hydrogeological working in the massif, with many problems for the water use, because the interference of natural data and human impact. Now, the massif play a part of a water-tank, subject to climate, hydrological behaviours and more and more to conditions of water use: particularly the problem of the increase of the summer drawing in a sequence of dry years with low winter recharge.

Understanding hydrological process of surface water and groundwater is significant for the management of urban water resources. In this study, a total of thirty-seven water samples have been collected from the river (RW, 15 samples), shallow aquifer (SG, 12 samples), and deep aquifer (DG, 10 samples) in Suzhou, Northern Anhui Province, China, and their major ion concentrations and stable H–O isotopes have been measured. The results revealed that Na+and HCO3−were the dominant cation and anion, respectively, and most of the water samples are classified to be Na-HCO3type, to a lesser extent, Mg-HCO3type. K-mean and Q-type clustering analyses ruled out the hydrological relationship between river and groundwater, but there was a significant connectivity between shallow and deep groundwater, which was further confirmed by the hydrogen and oxygen isotopes. The relationship between δ2H and δ18O has shown that precipitation was the main source of the groundwater in the study area. Furthermore, the values of deuterium excess (d-excess) in different water bodies suggested that the groundwater has not been affected by evaporation, which was the main process controlling the isotopic composition of river water.

The Baccatoio Stream basin (Apuan Alps) was subjected to numerous investigations linked to the presence of abandoned mines and related acid mine drainages. This study aims to achieve new insights into water circulation in carbonate aquifers feeding three of the major springs of the area (Moresco springs: VSMOA, VSMOS, VSMOG). VSMOA and VSMOS show evidences of hydraulic connection with Baccatoio stream, contaminated by acid mine drainages. The study focused on springs chemical and isotopic variations induced by a rainfall event. Some general conclusions can be drown: (i) the hydraulic connection between Baccatoio stream and VSMOA-VSMOS seems to be confirmed; (ii) during rainfall events, infiltrated rainwater seem to directly contribute to the perturbation of VSMOA-VSMOS; (iii) different flow fractions feeding VSMOA- VSMOS after rainfall pulse were quantified; (iv) VSMOG did not show any perturbation linked to the rainfall.

The fractured groundwater aquifers, predominantly found in South Africa, shows varying groundwater chemical characteristics in various locations. The hydrochemistry of groundwater is affected by the weathering of rock formations in contact and anthropogenic activities. Determination of groundwater chemistry is important for aquifer protection and overall groundwater management. A hydrochemical analysis is a useful tool for identification of water types, chemical composition, its suitability for specified purposes, and an important requirement for water use licensing applications. Groundwater hydrochemical data from 79 boreholes near Leliefontein, Kamiesberg local municipality of South Africa were analysed, using integrated statistical, geostatistics and spatial interpolation methods. The result shows the abundant cation and anion to be Na+ and Cl−. The mean concentration of Na was 267.39 mg/l, and that of Cl was 574.81 mg/l at Leliefontein. The ionic concentrations in groundwater was in sequence of Cl− > Na+ > HCO3- > SO42- > Ca2+ > Mg2+ > NO3- > Si > K+ > F-. The analysis indicated that cation exchanges in groundwater are influenced by limited silicate weathering, with calcite and dolomite dissolution. Geostatistical and spatial analysis interpolation for the major cation (Na) and major anion (Cl), Sodium Adsorption Ratio (SAR), Electrical Conductivity (EC) and Water Quality Index (WQI) was performed using Inverse Distance Weighing method. The hydrochemical data for Leliefontein groundwater were analysed to classify water for domestic use (drinking) and agriculture (irrigation) purposes, based on recommended guidelines of the South African National Standard (SANS). The study area was characterised by high salinity of three water types, viz, Na-Cl seawater type, Ca-Cl reverse ion-exchange water type, and Na-HCO3 base ion-exchange water types. About 70 – 80 % of the boreholes in Leliefontein met the requirement for irrigation application for Sodium Adsorption Ratio (SAR) and salinity hazard analysis, while the groundwater generally required further treatment before domestic use.

Peatlands are subject to increased pressure from environmental and land-use change, particularly in temperate regions such as the US Midwest. Bryophytes dominate the ground cover of peatlands and play a key role in their functioning. Effective management and restoration of degraded peatlands requires good understanding of their bryophyte communities, and how these are shaped by environmental conditions. Furthermore, bryophytes are sensitive indicators of environmental conditions. We monitored microhabitat characteristics (hydrology, hydrochemistry, abundance of vascular vegetation, microtopography) alongside bryophyte community composition in nine kettle hole mires in Ohio (USA). We found that the most important drivers of bryophyte community composition and diversity were water level and hydrochemistry. Sampling locations showing poor fen characteristics (high water level, pH and electrical conductivity) were associated with generalist pleurocarpous mosses (indicator species: Amblystegium serpens) and lower species richness. Where bog conditions prevailed, Sphagnum species dominated, and Sphagnum fallax and the liverwort Cephalozia sp. were indicator species.

Jambakan is a hamlet in Bayat District, Central Java Province, Indonesia, which commonly has brackish groundwater. Its unique geological profile leads to variation in groundwater quality that is even found between adjacent wells. This study was designed to identify the quality and hydrochemical type of groundwater and the distribution of brackish groundwater in Jambakan. It employed a quantitative method to analyzethe data collected in the field survey and groundwater quality data (major ions). Meanwhile, the hydrochemical facies of groundwater was interpreted from the plots of major ions on trilinear and quadrilateral Piper diagrams. The results showed that some of the groundwater quality parameters in six wells, namely A6, A34, A38, A65, A67, and A73, had exceeded the standard thresholds. The parameters in question were TDS, EC, salinity, sodium, calcium, chloride, sulfate, magnesium, and hardness. Compared with the six wells, A40 and A45 had better quality. The distribution of brackish groundwater could not be modeled horizontally because salinity highly depends on rock layers where the observed wells are located. Based on the trilinear Piper plots, the groundwater consisted of four hydrochemical facies, namely magnesium bicarbonate, a mixed type, calcium chloride, and sodium chloride. Meanwhile, the quadrilateral Piper diagrams showed the presence of Type I (bicarbonate water), Type II (semi-bicarbonate water), Type III (evaporite water), and Type IVb-IVc (sulfate water) in the groundwater of Jambakan Hamlet.

Mieux comprendre l'origine de la ressource en eau afin d'en améliorer la gestion est aujourd'hui une nécessité. Les cours d'eau de l'amont cévenol du bassin versant des Gardons, présentent des différences dans leurs débits de basses eaux. Ces écarts entre débits s'expliquent, hors des différences liées aux précipitations (orages...), par des contributions particulières des réservoirs géologiques, dans la mesure où les basses eaux correspondent globalement à un régime hydraulique non influencé (tarissement).L'étude a été réalisée principalement durant les étés 2018 et 2019. Les débits et la minéralisation des eaux de surface et des eaux souterraines ont été suivis sur neuf sous-bassins versants. Un modèle de mélange, appliqué en complément du suivi géochimique, permet de quantifier la contribution des différentes formations aquifères et montre de fortes différences entre elles. À l'étiage, deux formations, les micaschistes noirs et les calcaires, se révèlent primordiales dans le soutien des débits : elles alimenteraient les cours d'eau étudiés à hauteur de 41 et 17 % respectivement, alors qu'elles ne couvrent que 13 et 8 % du secteur considéré. L'analyse de la contribution des différentes formations permet d'expliquer les différences de débit spécifique observées pour les cours d'eau du terrain d'étude. Ces contributions à l'étiage, couplées aux débits, permettent d'identifier les réservoirs les plus productifs, qui sont à protéger en priorité. The increase in the severity of hydrological droughts in the Mediterranean basin in relation to climate change leads to the need to better understand the origin of the water resource to improve its management. The defined study area, the Cevennes upper watershed of the Gardons, presents quite significant variations in terms of low water flows. This article questions these differences and proposes to explain these variances in flows not by a rainfall difference but by a variation in the contribution of the geological reservoirs present in the different watersheds.The study was conducted mainly during the summers of 2018 and 2019 where flows and geochemistry of surface water and groundwater were monitored in 9 watersheds. The use of mixing model in addition to this geochemical-hydrological coupling allows to quantify the contribution of the different formations and shows strong contrast between them. At low water, two formations, black micaschists and limestone, appear to be essential to sustain the flow: they would feed the streams studied to the extent of 41 and 17 % respectively, while they cover only 13 and 8 % of the considered area. The analysis of the contribution of the respective geological formations allows to explain the observed specific discharge of the rivers in the study area.This information of contribution in low water coupled with the flow allows to identify the most productive reservoirs and could help to prioritize the protection of these in view of the scarcity of the resource that will result from climate change.

Study region Glacierized catchments in Central Asia Study focus The literature on hydrochemistry and water quality was reviewed to identify gaps in knowledge required to understand and quantify the impacts of climate change and deglacierization. New hydrological insights for the region The main knowledge gap was the characterization of hydrochemistry and water quality along the elevation continuum from glaciers to arid plains. The chemical composition of snow and glacier ice are understood relatively well but the pathways of pollutants stored in glacier ice and released with melt into the aquatic systems are not researched. There is a lack of publications on the release of organic carbon following deglacierization and element leaching from the exposed substrate, permafrost and rock glaciers. Snow and glacial melt dilutes pollutants along the river channels, reducing concentrations and mostly ensuring the compliance with water quality standards including downstream locations. Poor surface water quality is associated with irrigation, the practice of soil washing, and discharge of the untreated sewage. There is a notable lack of information about the links between snow and glacier melt, aquifer recharge and groundwater quality and this is a major gap in knowledge affecting environmental and health protection. Better understanding and quantification of factors and processes controlling hydrochemistry and water quality is needed to adapt to the impacts of the imminent deglacierization.

Lakes are important natural water reservoirs that connect other water bodies and play essential roles in water supply, ecological preservation, and climate regulation. Because of global climate change and human activities, many lakes worldwide are facing severe challenges, such as ecological degradation and reductions in their water storage, levels, surface areas, and quality. Water diversion into lakes is considered an effective measure to address these challenges and has attracted much attention. Water has been diverted into Lake Ulansuhai through drainage channels from the Yellow River since 2013. This shallow lake is located in arid northern China and is greatly affected by high salinity and eutrophication. The lake is the lowest area in the Hetao basin and is a sink for terrestrial water in this region. High salinity in lake water, drainage channels, and groundwater caused by NaCl is an ongoing problem, however, water diversion has played an important role in dilution. The main hydrochemical type in the lake water is Cl·HCO3–Na·Mg, while those in the drainage channels and the groundwater show more diversity because of spatial differences. The main source of water in the lake (52–60%) is that diverted through six drainage channels on the west bank, followed by meteoric precipitation (36–38%). Groundwater recharge to the lake is minimal (west bank: 2–7%, and east bank: 1–5%). Extensive evaporation occurs in the lake before the lake water is discharged into the Yellow River through a waste canal. The hydrochemical evolution and salinization of the lake are dominated by the six drainage channels, followed by evaporation from the lake surface. Thus, resolution of soil salinization in the Hetao irrigation area is key to addressing salinity issues in the lake. This study will be helpful for the planning of future water diversion and ecological restoration.

Transport of carbon, major and trace element by rivers in permafrost-affected regions is one of the key factor of circumpolar aquatic ecosystem response to climate warming and permafrost thaw. While seasonal and annual export fluxes (yields) of carbon (C) and inorganic solutes are fairly well known for all large Arctic rivers, spatial variations in elementary concentration along the river length and among its tributaries remain poorly understood. Moreover, the landscape factors controlling riverine element concentration in permafrost-affected regions are still poorly constrained. This is especially true for the largest river of Eastern Siberia, the Lena River, which drains through continuous permafrost zones with highly variable lithology and vegetation. Here we present the results of C, major and trace element measurements over a 2600-km transect of the Lena River main stem (upper and middle reaches) including its 30 tributaries, conducted at the peak of the spring flood. There were two main group of solutes in the main stem depending on their spatial pattern: i) elements that decreased their concentrations downstream, from SW to NE (Cl, SO4, DIC, Li, B, Na, Mg, K, Ca, As, Sr, Mo, Sb, Ba and U), which probably reflected a decrease in the proportion of carbonate rocks in the watershed and the degree of groundwater feeding, and ii) elements that increased their concentrations downstream (Al, Ti, Cr, Fe, Ga, Rb, Y, Zr, Nb, Cs, REEs, Hf and Th), which was tentatively linked to an increase in organic C stock in soils, larch forest coverage and enhanced mobilization of lithogenic elements from silicate soil minerals. Based on landscape parameters of Lena tributaries, we tested the impact of major environmental factors on major and trace element spatial pattern. Among all the variables, the proportion of sporadic permafrost on the watershed strongly controlled concentrations of soluble highly mobile elements (Cl, B, DIC, Li, Na, K, Mg, Ca, Sr, Mo, As and U). Another important factor of element concentration control in the Lena River tributaries was the coverage of watershed by light (B, Cl, Na, K, U) and deciduous (Fe, Ni, Zn, Ge, Rb, Zr, La, Th) needle-leaf forest (pine and larch). The latter, however, could also reflect the DOC-enhanced transport of low-soluble trace elements in the NW part of the basin. This part of the basin is dominated by silicate rocks and continuous permafrost, as compared to carbonate rock-dominated and groundwater-affected SW part of the Lena River basin. Overall, the impact of rock lithology and permafrost on major and trace solutes of the Lena River basin during the peak of spring flood was mostly detected at the scale of the main stem. Such an impact for tributaries was much less pronounced, because of the dominance of surface flow and lower hydrological connectivity with deep groundwater in the latter. Future changes in the river water chemistry linked to climate warming and permafrost thaw at the scale of the whole river basin are likely to be linked to changes in spatial pattern of dominant vegetation, rather than to the permafrost regime. We argue that comparable studies of large, permafrost-impacted rivers during most contrasting seasons, including winter baseflow, should allow efficient prediction of future changes in riverine ‘inorganic’ hydrochemistry induced by permafrost thaw.

Several thousand coastal perennially ice-covered oligotrophic lakes and ponds have been identified on the Antarctic continent. To date, most hydrochemical studies on Antarctica’s ice-covered lakes have been undertaken in the McMurdo Dry Valleys (more than 20 lakes/ponds studied since 1957) because of their proximity to the McMurdo research station and the New Zealand station Scott Base. Yet, little attention has been given to coastal ice-covered lakes situated in Antarctica’s central Queen Maud Land region, and more specifically in the Untersee Oasis: a polar Oasis that encompasses two large perennially ice-covered lakes (Lake Untersee & Lake Obersee), and numerous small ice-covered morainic ponds. Consequently, this PhD research project aims to describe and understand the distribution, ice cover phenology, and contemporary hydrochemistry of perennially ice-covered lakes and ponds located in the Untersee Oasis and their effect on the activity of the benthic microbial ecosystem. Lake Untersee, the largest freshwater coastal lake in central Queen Maud Land, was the main focus of this study. Its energy and water mass balance was initially investigated to understand its current equilibrium and how this perennially well-sealed ice-covered lake may evolve under changing climate conditions. Results suggest that Lake Untersee’s mass balance was in equilibrium between the late 1990s and 2018, and the lake is mainly fed by subglacial meltwater (55-60%) and by subaqueous melting of glacier ice (40-45%). A recursive stable water isotope (δD-δ18O) evolution model for well-sealed perennial ice-covered lakes that takes into account the effect of changing chemistry in residual waters on δD-δ18O values was then developed and determined that Lake Untersee is in isotopic steady-state. Modeling results also showed that Untersee most likely did not receive additional inputs from surface streams during the last 300–500 years at the time of sampling, in November-December 2017. However, in mid-January 2019, Untersee experienced a glacial lake outburst flood (GLOF) that increased the water level by 2 m (contributing 1.75×107 m3 of water), modifying its water chemistry and inorganic carbon load. High-resolution grain size and carbon isotope analyses of the benthic microbial mats suggest that GLOFs occurred periodically over the Holocene and that those events sporadically increased the primary productivity of its benthic microbial ecosystem. Finally, ice-covered ponds in the Oasis were identified and sampled to compare their morphometric properties, hydrochemical properties, and microbial mat activity with Lake Untersee. It was discovered that the Untersee Oasis ponds offer the full spectrum of ice cover types (i.e., perennial well-sealed, perennial and moat forming, and seasonally ice-covered) and that their hydrochemical properties depend on ice cover type. Empirical pond data was used to determine how Lake Untersee and the ponds themselves will evolve as they transition under a warming climate from well-sealed to moat forming and from moat forming to seasonally ice-covered.

Isotope data and major ion chemistry were used to identify aquifer recharge mechanisms and geochemical evolution of groundwaters along the US–Mexico border. Local recharge originates as precipitation and occurs during winter through preferential infiltration pathways along the base of the Gila Range. This groundwater is dominated by Na–Cl of meteoric origin and is highly concentrated due to the dissolution of soluble salts accumulated in the near-surface. The hydrochemical evolution of waters in the irrigated floodplain is controlled by Ca–Mg–Cl/Na–Cl-type Colorado River water. However, salinity is increased through evapotranspiration, precipitation of calcite, dissolution of accumulated soil salts, de-dolomitization, and exchange of aqueous Ca2+ for adsorbed Na+. The Na–Cl-dominated local recharge flows southwest from the Gila Range and mixes with the Ca–Mg–Cl/Na–Cl-dominated floodplain waters beneath the Yuma and San Luis Mesas. Low 3H suggests that recharge within the Yuma and San Luis Mesas occurred at least before the 1950s, and 14C data are consistent with bulk residence times up to 11,500 uncorrected 14C years before present. Either the flow system is not actively recharged, or recharge occurs at a significantly lower rate than what is being withdrawn, leading to aquifer overdraft and deterioration.

International audience; Simultaneously acquiring time series of climate, hydrology and hydrochemical data over decades on river systems is pivotal to understand the complex interactions involving rock, soil water, air and biota in the Critical Zone, to build integrated modelling and to propose predictive scenarios. Among the Critical Zone Observatories (CZOs) implemented in the past 25 years, only a few are located in the humid Tropics despite the importance of these regions in terms of population density, fast-changing land use, biodiversity hotspots, biomass stock on continents, size of river systems, etc. Since 1994, weathering and erosion processes and fluxes have been investigated at both local (experimental watershed) and regional scales in the Nyong River Basin (Cameroon) which belongs to the Critical Zone Observatories network named Multiscale TROPIcal CatchmentS (M-TROPICS). The data shared by M-TROPICS in Cameroon are: (1) rainfall; (2) air temperature, air relative humidity, wind speed and direction, and global radiation; (3) stream and river water level; (4) pH, electrical conductivity, water temperature and suspended particulate matter (SPM) concentration; (5) major ion, alkalinity and dissolved organic carbon (DOC) concentrations. The dataset already contributed to describe the water partitioning in these tropical humid watersheds, to better understand the factors controlling chemical weathering and physical erosion in tropical ecosystems, particularly the role of organic matter. The dataset also contributed to calculate elemental weathering fluxes and saprolite production rate and to propose denudation rates on tropical cratonic landscapes. Hydrological modelling allowed quantification of the geographical water sources contributing to streamflow. DOC data were used to determine greenhouse-gas emissions and carbon budgets from African inland waters. However, long-term solute concentrations at the outlet of a small tributary of the Nyong River exhibit non-stationary behaviour over the last 26 years. The processes governing those fluctuations are not yet fully understood and might be related to changes in the hydrological regime, land-cover and land-use. The latter highlights the need for longer time-series and continued support for CZOs particularly in the humid tropics.

Study region Eight Coastal aquifers (CA) of Bakhtegan and Tashk lakes (BTL) and salt marsh, southern Iran Study focus BTL, Wetlands of International Importance, have been shrinking due to reduction in surface discharge, groundwater overexploitation, and drought. We show that this resulted in an increase of BTL total dissolved solids (TDS) from 45400 to 256000 mg/l. To characterize the hydrogeological behavior of the coastal aquifers after shrinkage, major ions, TDS and water level were measured along a transect from inside the BL to one of the aquifers. The spatial distribution of electrical conductivity (EC), discharge and iso-potential maps was determined. A support vector regression technique was used to forecast EC and water level in CA for the next decade. New hydrological insights for the region Five zones based on EC changes and hydraulic gradient are recognized, namely: brine, highly saline, brackish, transition, and freshwater. The groundwater flow direction is from both the BTL and Fresh Water Zone, converging towards the intermediately positioned Transition Zone. Saltwater intrusion is active based on the hydraulic gradient towards the land and the gradient of water density. A schematic flow model of CA was proposed based on active SWI, groundwater flow direction, and chemical signature. Forecasting reveals a significant further deterioration of water quality and drop in groundwater levels, which emphasizes the need for systematic and sustainable water management.

This article presents hydro-chemical and isotopic (delta N-15-, delta O-18-NO3-, delta B-11) data of water samples and potential nitrate sources from the Nyando river basin, a tributary of the Lake Victoria in Kenya. The data collection involved field sampling of water samples in 23 sampling stations spatially distributed in the basin during nine seasons from July/2016 to May/2018. The hydro-chemical data was generated from the Laboratory analysis of the water samples using the ion chromatogram. Samples for nitrate isotope (delta N-15-, delta O-18-NO3-) analysis were prepared via the bacterial denitrification method and analysed using Isotope Ratio Mass Spectrometer. The data, which is categorised in different land use zones and seasons, is important for understanding the spatiotemporal variation in nitrate and solute concentrations and the role of land use on the river water quality. In addition, the delta N-15-, delta O-18-NO3- and delta B-11 values are key for elucidating nitrate pollution sources and potential biogeochemical processes for the management and control of nutrient pollution and eutrophication of the Lake Victoria. Furthermore, the dataset can be of great use in water quality models for understanding non-point pollution dynamics in tropical basins. This article is related to [1]. (C) 2021 The Authors. Published by Elsevier Inc.

Hydrochemical investigation of open well and river water samples of Thuthapuzha Sub-basin of Bharathapuzha, Kerala, was carried out to determine the spatial and temporal variations in the physico-chemical parameters. The suitability of water for drinking and irrigation purposes and the processes controlling the water chemistry were also assessed. The study area experiences a humid tropical climate and heavy rainfall of ~ 3830 mm/year. Thirty-five open well and nine river water samples were collected during the pre-monsoon, monsoon and post-monsoon seasons. The chemical properties of the river water samples were dominated by alkaline earths and weak acids (CaHCO3 type). Even though majority of the open well samples belonged to CaHCO3 type, few samples belonged to NaCl, mixed CaMgCl and mixed CaNaHCO3 water type. The groundwater and river water chemistry of the region was influenced by the chemistry of the host rock rather than precipitation and evaporation. Except pH and the total iron concentration, all other physico-chemical parameters of the open well samples of the study area were within the acceptable limit of drinking purposes. The physico-chemical parameters of the entire river water samples were within the acceptable limit for drinking purpose. The entire open well and river water samples were suitable for irrigation purposes.

With a flow estimated at 1200 m3∙s−1 and a height of 8 m downstream, the flood that occurred on October 10, 2008 spread along the M’zab River over a length of more than 180 km. Material and human damage is visible, but its effects on the quality of the waters of the alluvial layer remain unknown: this is the purpose of this paper. Samples of groundwater were taken during the period 2005–2012 in 4 oases of the valley. Physicochemical analyses were performed using molecular and flame spectroscopic methods and also volumetric methods on water samples. The results obtained were interpreted using histograms and hydrochemical diagrams, such as the Avignon software (L.H.A) (version 4, 2008). Low effect of flood on the water quality of the alluvial aquifer was manifested by concentrations of magnesium sulphate and calcium chloride. On the other hand, there is an accumulation of salts infiltrated by sewage except for the zone of Bouchen. The diagrams show that there is an improvement in water quality in this area.

Study of natural and anthropogenic processes in the southern seas of Russia is a priority task of the Southern scientific center of Russian Academy of Sciences. Annually for 15 years, the Southern scientific center of RAS carried out sea expeditions in the south of Russia. The year of 2017 was marked as a 10-year anniversary of the first expedition of the R/V Deneb in the Azov and Black seas. During a five-year period from 2012 to 2016, 36 complex expeditions in the Azov and Black seas were carried out by R/V Deneb; the oceanographic database was enriched with the data of 3500 oceanological stations, more than 11,000 samplings were done at more than 900 complex hydrobiological stations. The expeditionary materials enlarged the oceanographic database of the Southern scientific center: the field and archival data permitted to assess long-term dynamics of organic matter and carbon, the Azov Sea transparency and salinity and to calculate the characteristics of small-scale variability of temperature, salinity, internal waves and level fluctuations in the Azov and Black seas. The research in the Black Sea provided extensive synchronous data which characterize current state of the most vulnerable psammophilic benthic communities at the depths of 2–20 m. The estuaries of small rivers at their junction with the sea were studied in details. The new data on distribution and quantitative characteristics of jelly-like-, phyto- and pico-plankton over the whole shelf area of the Russian sector of the Black Sea is obtained. The Black Sea population of newcomers – Holland crabs (Rhitropanopaeus harrisi tridentate) – living exclusively in the sea canyons with unstable salinity was studied. The metagenomic approaches applied to study the plankton communities in the Azov and Black seas, were used to obtain new data on diversity and structure of marine bacterial communities. The oceanological observation data on the environment conditions in the Azov and Black seas are annually directed to the Hydrographic department of the Black Sea Navy of Russian Federation where it is used in the field service.

Groundwater samples from Turonian aquifer of Béchar region were evaluated as drinking and irrigation water sources. physicochemical parameters including pH, EC, TH, Na+, Ca2+, Mg2+, Cl−, SO42– and NO3− were determined for 16 water sampling points. These characterizations show that the groundwater is fresh to brackish, slightly alkaline and the major ions are Na+, Ca2+, Mg2+, Cl− and SO42–. According to WHO standards, 50% of the analysed water are suitable as a drinking source while the other samples are not in compliance with drinking water standards. This non-compliance is basically due to the high concentrations of Na+, Cl−, and SO42– requesting further treatment to reach the stringent standards. According to the results of nitrate concentrations, anthropogenic source seems to influence the groundwater quality. The present study shows that Béchar groundwater may represent an important drinking and irrigation water source. However, a specific management strategy should be adapted in order to avoid the contamination by anthropogenic sources.

Groundwater demand has increased due to overpopulation and intensive irrigation which resulted in decline of water resources and deterioration of water quality. In this view, a microlevel study was conducted through hydrogeochemical investigation and resistivity survey (VES) in Kalanad river basin, Kasaragod, Kerala. The study aims to determine the spatial variations in physicochemical parameters with delineation of geological layers of the study area through VES. Hydrogeochemical investigation and water suitability assessment for drinking and irrigation purposes were confined to open well water samples of the study area. The sample analysis and comparison with various standards (WHO and BIS) show that the groundwater is not entirely fit for drinking with respect to pH. Almost all samples fall within standard values as per the irrigation water quality indices. The chemical nature of the groundwater samples was dominated by alkalies and majority of the samples belonged to sodium chloride type. This study also dealt with the interpretation of hydrogeochemical data using correlation and R mode factor analyses. VES was carried out at seven locations, and the apparent resistivity values obtained had been analysed. The interpretation delineated a maximum of four geologic layers in the study area. The sequence of geologic formation is composed of highly resistive top lateritic soil followed by saturated zone and then the basement topography in the entire basin.

Tropical rivers such as the Rio Negro constitute a major portion of the global aquatic flux of dissolved organic carbon (DOC) entering the ocean, but the exact amount, source contributions and fate of terrestrial DOC remain unknown. We investigated the role of valley and upland whitesand ecosystems (WSEs) and terra firme plateaus in forming blackwater tributaries in the Rio Negro basin to develop novel constraints for the terrestrial export of carbon. 5709 molecular markers from ground- and surface waters of two contrasting valley and upland sites feeding Rio Negro tributaries were identified by ultrahigh resolution mass spectrometry (FT-MS), analyzed by multivariate statistics and compared to known Rio Negro markers. In a Principal Coordinates Analysis, valley and upland DOC molecular composition differed by 78% from plateau DOC, which was characterized by reworked, aliphatic and unsaturated N- and S-containing molecules, while valley and upland DOC contained mainly condensed aromatics, aromatics and oxidized unsaturated structures. Valley and upland samples differed by 10% in molecular DOC composition and by their isotopic content (14C of SPE-DOC, 18O and 2H of water) which indicated differences in hydrology and C turnover. Against expectation, markers of widespread whitesand valleys did not emerge as a major source of Rio Negro markers, but specific upland markers did. Pubchem suggested chromene and benzofuran structures as promising candidates for further study. Our findings indicate that the export of molecular markers diverges from expected transport-limited DOC behavior, and thereby opens new avenues for source annotation beyond DOC quantity. Terrestrial DOC from upland whitesand areas is a major source of specific blackwater molecules missing in the regional ecosystem C balance, whereas C export from the whitesand valleys and especially from terra firme plateaus represents mainly recycled and transformed carbon not directly affecting the ecosystem C balance and possibly, the watersheds downstream molecular signature. Our study highlights the potential of high-resolution techniques to constrain carbon balances of ecosystems and landscapes by novel molecular markers. A comparison with other terrestrial DOM datasets indicated molecular similarities with temperate acidic soils and tropical rivers that warrant further analysis of common DOM markers. Implications, limitations, and future challenges are discussed in the light of potential applications of diagnostic molecular links for DOC source annotation and estimation of terrestrial DOM export in the land-to-ocean continuum., Geochimica et Cosmochimica Acta, 311, ISSN:0016-7037, ISSN:1872-9533

Pumped storage hydropower (PSH) enables the temporary storage of energy, including from intermittent renewable sources, and provides answers to the difficulties related to the mismatch between supply and demand of electrical energy over time. Implementing a PSH station requires two reservoirs at different elevations and with large volumes of water. The idea of using old, flooded open-pit quarries as a lower reservoir has recently emerged. However, quarries cannot be considered as impervious reservoirs, and they are connected to the surrounding aquifers. As a result, PSH activities may entail environmental impacts. The alternation of the pumping–discharge cycles generates rapid and periodic hydraulic head fluctuations in the quarry, which propagate into the surrounding rock media forcing the exchange of water and inducing the aeration of groundwater. This aeration can destabilize the chemical balances between groundwater and minerals in the underground rock media. In this study, two numerical groundwater models based on the chalk quarry of Obourg (Belgium) were developed considering realistic pumping–discharge scenarios. The aim of these models was to investigate the hydrodynamic and hydrochemical impact of PSH activities on water inside the quarry and in the surrounding rock media. Results showed that (1) water exchanges between the quarry and the adjacent rock media have a significant influence on the hydraulic head, (2) the frequency of the pump–discharge scenarios influence the potential environmental impacts, and (3), in the case of chalk formations, the expected impact of PSH on the water chemical composition is relatively limited around the quarry. Results highlight that those hydrogeological and hydrochemical concerns should be assessed when developing a project of a PSH installation using a quarry as a lower reservoir, considering all particularities of the proposed sites., This research was supported by the Public Service of Wallonia, Department of Energy and Sustainable Building in the framework of the SMARTWATER project. IDAEA-CSIC is a Centre of Excellence Severo Ochoa (Spanish Ministry of Science and Innovation, Project CEX2018-000794-S). E.P. was also funded by the Barcelona City Council through the Award for Scientific Research into Urban Challenges in the City of Barcelona 2020 (20S08708)

The present study focuses on the hydrochemical conditions of a coastal mangrove lagoon in Venezuela which is completely isolated from the sea, lacking any visible connections such as tidal channels, preventing in this way tidal flushing. These isolation conditions introduced important changes in vegetation, soil salinity and hydrology. The aim of this paper is to relate some of the effects of disconnection, with the potential use of the mangrove as a sewage pond for treated domestic wastewater. Available data are analyzed on soil properties, hydrochemistry and water level fluctuations of surface and groundwater, recorded through a whole hydrological year. Present day mangrove characteristics are examined through the scrutiny of recordable historical disturbances. Finally, the potential effect of treated wastewater to be supplied to the lagoon is estimated, on the basis of local climate trends. It is concluded that the present day surface water quality would be impaired, and the desalinization process of soil and groundwater accelerated. The annual volume of residual water to be supplied would equal a 20% increase in the local precipitation regime, supply that would deeply alter the existing flood/drought regime. It is suggested that recuperating the original mangrove connection to the sea through channel opening may alleviate the impact of wastewater discharge. S'estudien les condicions hidroquímiques d'una llacuna costanera de manglar que es troba actualment aïllada del mar, a la qual li manquen connexions visibles amb aquest com canals o rambles de marea; no està per tant sotmesa a l'acció de la marea. Aquest aïllament ha provocat canvis importants en la composició de la comunitat de manglar, en el contingutde sals del sòl i en les característiques hidrològiques. L'objectiu d'aquest estudi és relacionar alguns dels efectes de l'aïllament sobre la llacuna de manglar i el seu ús potencial com a receptora d'aigües residuals tractades d'un complex hoteler veí. S'analitzen dades disponibles dels sòls, hidroquímica i fluctuacions del nivell d'aigües superficials i subterrànies, registrades durant un cicle hidrològic complet. Les característiques actuals del manglar s'estudien mitjançant dades històriques. Finalment, l'efecte de la incorporació d'aigües residuals tractades a la llacuna s'avalua en base a les tendències climàtiques locals. Es conclou que la qualitat de l'aigua de la llacuna actual podria empitjorar amb la descàrrega de les aigües residuals i que el procés de desalinització existent s'acceleraria. El volum anual d'aigua afegit equivaldria a un increment del 20% de la precipitació actual. Aquest suplement d'aigua dolça podria alterar profundament el règim d'inundació / sequera del present. Per alleugerir l'impacte de la descàrrega d'aigua tractada a la llacuna, se suggereix recuperar les connexions originals del manglar amb el mar.

Peatlands comprise of approximately half of the Athabasca oil sands region, many of which overlay some of the world’s largest bitumen deposits where surface mining for this resource has permanently altered the landscape. By law, companies must reclaim disturbed landscapes into functioning ecosystems including integrated upland-wetland systems with the objective of forming sustainable peat-forming wetlands. This thesis presents six years (2013 – 2018) of water balance and associated salinity data from one of the two existing constructed upland-wetland systems, the Sandhill Fen Watershed (SFW), a 52-ha upland-wetland built on soft tailings to evaluate the hydrological and hydrochemical performance and its potential to be self-sustaining. Following a considerable decrease in hydrological management, the dominant water balance components changed from primarily horizontal (inflow and outflow) to vertical fluxes (precipitation and evapotranspiration) which increased inundation, encouraged salt accumulation and changed plant communities. Results suggest that current conditions are not favourable for fen-peatland development as marsh-like conditions have developed, limiting water conserving functions and the ability to persist long-term in a changing climate. In terms of winter processes, topography currently controls snow accumulation, redistribution and melt at SFW while the role of vegetation in these processes is expected to increase as it continues to develop. Runoff ratios of snowmelt from hillslopes were drastically different than those previously reported for reclaimed peatland watersheds highlighting the influence of different soil materials used during construction. Under various climate change scenarios of a warmer and wetter climate, results from the Cold Regions Hydrological Model indicate that the influence of winter processes will decrease, potentially putting reclaimed systems at greater risk of moisture stress. Substantial hydrochemical changes have occurred as salinity was relatively low at the study onset as high volumes of inflow and outflow prevented ion accumulation. Over time, salinity continued to increase year-over-year throughout SFW from 2013 to 2018 in the wetland and margin areas. This increase in site-wide salinity was attributed to the shift in dominant water balance fluxes, changes in water table position and increased mixing of SFW waters with deeper saline groundwater that underlies the system. Based on its current conditions, it is unlikely that SFW will support peat-forming vegetation. It is recommended that design strategies shift to incorporate characteristics found in undisturbed saline peatlands that are capable of supporting peat-forming vegetation in a saline environment. Thesis Doctor of Philosophy (PhD) A better understanding of the hydrological functioning of reconstructed peatlands in the Athabasca oil sands region is required as it is a novel approach in this region and there is potential for thousands of hectares of land that will require this reclamation in the future. Due to their recent establishment potential trajectories of constructed peatlands have yet to be fully analyzed as only recently has sufficient data been collected to evaluate the hydrological and hydrochemical functioning and provide insight on its overall success. While design strategies may seem sound, these constructed systems are completely human-made and it is unclear how they will develop and function in a highly disturbed landscape. Thesis results suggest that current conditions are not favourable to sustain a peatland as marsh-like conditions have developed which will limit its ability to persist long-term in a dry and changing climate. It is recommended that design strategies shift to incorporate characteristics found in undisturbed saline peatlands that are capable of supporting peat-forming vegetation in a saline environment. Due to the many challenges associated with reclamation in this region, lessons learned from this pilot project will help guide future peatland construction.

Karst water is vital for local drinking and irrigation but is susceptible to contamination. Hydrochemistry, which is highly related to carbonate weathering in karst catchments, can affect water quality and respond rapidly to climate change. In order to explore hydrogeochemical sources, dynamics, and their responses to rainstorms, rainwater, throughfall, hillslope runoff, surface water, and groundwater were sampled synchronously during rainstorms at a karst Critical Zone Observatory (CZO), Southwest China. Results showed that the total dissolved solids (TDS) concentration in throughfall increased by 30.1 ± 8.0% relative to rainwater, but both throughfall and rainwater contributed little to TDS in surface water and groundwater compared with terrestrial sources. Hydrochemistry in surface water and groundwater was diluted by rainstorms but displayed chemostatic responses with different intensities to increasing discharge. This is possibly regulated by hydrogeological conditions, available sources of various solutes, and the difference between solute concentrations before and after rainstorms. Ca2+ and Mg2+ dynamics were mainly regulated by carbonate weathering, gypsum dissolution, and gypsum-induced dedolomitization (geological sources), which also affect Ca2+, Mg2+, and SO42- in deep confined groundwater draining a gypsum stratum. For HCO3-, CO2 from respiration and microbiologic activities is one dominant contributor, especially for spring. The chemostatic behaviors of NO3-, Cl−, and K+ were related to agricultural activities, especially in surface water. These controls on hydrochemistry may already exist as hillslope runoff occurs, which has be further demonstrated by principle component analysis (PCA). The heterogeneous permeability of epikarst can affect the mixture of groundwater from different sources and flowing pathways, enabling hydrochemistry at different hydrogeological conditions to display discrepant responses to rainstorms. The epikarst aquifer with high permeability is susceptible to changes in external environment, such as rainstorms and agricultural activities, increasing the potential risk of water environment problems (chronic pollution of nitrogen and high hardness of water) during a certain period. Drinking water safety thus deserves consideration in the agricultural karst catchment.

Study region The Nyando River basin in western Kenya. It is part of the Lake Victoria basin. Study focus As a first step towards numerical modeling, complementary datasets from different periods have been used to develop a conceptual hydrogeological model for this geologically complex basin. The study focused on characterizing the physical and process structures. Data from geological reports and geo-electrical survey reports were used to establish aquifer extents. Timeline comparison and interpolation of groundwater levels and hydrochemical data analysis were used to define groundwater flow characteristics. New hydrological insights for the region A highland and a Kano Plains groundwater system exist and are separated by the faults at the Nandi and Kendu escarpments. The groundwater divide between Nyando and Nyamasaria Rivers flowing through the Kano Plains is indistinct, suggesting that their lowland groundwater system is the same. Kano Plains has a shallow and deep groundwater system, both occurring in highly heterogeneous and aquifers; the bedrock here occurs at >250 m below ground level. Generally, the groundwater flow is topography driven towards Lake Victoria, but it is not clear whether it discharges here. Rainfall has minimal effect on long-term groundwater variability. Because groundwater levels do not change significantly over time, steady-state groundwater flow occurs in the plains.

This study analyzed the hydrochemical characteristics and microbial communities of karst water in Samcheok, Korea, and compared water quality results to identify the seasonal characteristics and hydrogeological connectivity of the study areas of Hamaengbang-ri, Gyogok-ri, Yeosam-ri, and the downtown area of Samcheok. Field survey and water quality analysis were performed in July 2019, February 2020, and April 2020. Hydrochemical analysis of karst water (groundwater and surface water) showed that most samples were comprised of Ca-HCO3 and that water&ndash, rock interactions were a dominant factor compared to precipitation and evaporation (crystallization). For seasonal characteristics, water&ndash, rock interactions appeared more active in the dry season than in the rainy season. Calcite weathering was dominant in the dry season, whereas dolomite weathering dominated the rainy season. Moreover, the saturation indexes for the dry and rainy seasons were less than and greater than 0, respectively, corresponding to an unsaturation (oversaturation) state, thus, white precipitate distributed in the study areas was deposited in the rainy season. Finally, as a result of analyzing the hydraulic characteristics between regions, hydrogeological similarities were identified between Hamaengbang-ri and Yeosam-ri, and between Gyogok-ri and downtown Samcheok, which suggested hydrogeological connectivity between each of the pairs.

Concentration&ndash, discharge (C-Q) relationships are a convenient and increasingly popular tool for interpreting the episodic hydrochemical response to the varying discharge in small basins, providing insights into solute transport and streamflow generation. While most studies are focused on total runoff, this study quantified C-Q relationships in four runoff components during precipitation events at the Hydrohill experimental catchment in Chuzhou, China. This unique artificial catchment is carefully engineered, allowing observations of the interacting runoff components that collectively determine total flow issuing from the catchment. The four runoff components, or flow paths, include surface runoff (SR), shallow interflow at 0&ndash, 30 cm depth (SSR30), deeper interflow at 30&ndash, 60 cm depth (SSR60), and groundwater flow at 60&ndash, 100 cm depth (SSR100). Water samples were collected during three consecutive precipitation events to study how the concentrations of primary solutes vary with flow. Analysis of C-Q relationships reveals that concentrations of Na+, Ca2+, Mg2+, SO42&minus, and HCO3&minus, in the four runoff components had a negative relationship with discharge, while the concentration of K+ and Cl&minus, were negatively correlated with discharge in SR and SSR30 but positively correlated in SSR60 and SSR100. Further insights were gained from principal component analysis. Three eigenvectors explained 92% of the variability in hydrochemistry in surface runoff, while two eigenvectors explained most of the variability in the hydrochemistry of subsurface flows observed at various depths in the soil profile (73% for SSR30, 79% for SSR60, and 76% for SSR100). PC1 (the first Principal Component) can be interpreted as a salinity factor, deriving from carbonate minerals such as dolomites and limestone minerals. Results indicated that leaching and dilution processes, water&ndash, soil interaction, and macropore flows in soils are the primary factors controlling the C-Q relationships. Our work sheds light on the coupled processes and streamflow generation mechanisms that control water quality at the catchment scale.

This study compares two mangroves with different land uses in the Jaguaribe River estuary, harboring large shrimp farms, and in the more pristine Pacotí River estuary. Normalized Difference Vegetation Index (NDVI) was used to compare the overall health of the forests. Measures of suspended matter (TSS), total (TP), particulate (PartP) and soluble reactive phosphorus (SRP) in the inflow and outflow waters of tidal channels draining the mangroves were performed during tidal cycles. NDVI varied from 0.65 in the Jaguaribe estuary to 0.85 in the Pacotí, suggesting the impact of shrimp farm effluents on mangrove canopy cover. The shrimp farm influenced site showed 10 times larger absolute ∑P (TP + PartP + SRP) = 1.2-5.2 kg.hr-1) flux than the pristine site (∑P = 0.22 kg.hr-1). Tidal balances showed smaller retentions of the total influx: 28-54%; 44-45%; 38-65% and 8-53% for TSS; TP; SRP; and PartP respectively, in the shrimp farm influenced site to over 93% of the total tidal input of TSS and all P fractions in the pristine mangrove. This suggests that mangrove phosphorus accumulation is decreased in the forest with lower NDVI and limits mangrove’s potential as a natural barrier to the nutrient transport to adjacent estuarine and coastal waters.

Through the practice of irrigation, surface water reservoirs (SWRs) contribute to the socio-economic development and food production activities of populations in Sub-Saharan Africa (SSA). However, they tend to dry up prematurely. One solution to circumvent these irrigation water shortages is to ensure their conjunctive use with groundwater. The objective of this study is to better understand the contribution of SWRs to groundwater recharge and to determine if groundwater may be considered as a complementary local resource for irrigation. The study was carried out on two watersheds in Burkina Faso, Kierma and Mogtedo. The spatiotemporal analysis of piezometric and SWRs level records coupled with physico-chemical analyses of water was used to characterize exchanges between SWRs and groundwater. The regional groundwater recharge at the scale of the watersheds was assessed. At the SWRs scale, a water balance methodology was developed and used to estimate focused recharge. The results show that SWRs interact almost continuously with groundwater and contribute focused recharge. The magnitude of this recharge is a function of the geological context and the sediment texture of the SWRs. It is estimated at 5 mm/day in Kierma and 4 mm/day in Mogt&eacute, do. These values are higher than the natural recharge estimated at 0.2 mm/day in Kierma and 0.1 mm/day in Mogt&eacute, do. Additionally, the values of hydraulic conductivity are between 0.01 and 2 m/day in Kierma and between 1 &times, 10&minus, 4 and 0.2 m/day in Mogt&eacute, do. These conductivities could allow pumping in large-diameter hand-dug wells with a significant yield between 0.5 and 120 m3/day in Kierma and between 0 and 10 m3/day in Mogt&eacute, do to palliate the early drying up of the SWRs.

Springs are natural outflows of groundwater to the surface and are often the only places to gain insights into underground processes, especially in protected areas. Contact with rocks changes the parameters of water, especially its chemical composition, which can be easily expressed via hydrochemical typing using the Szczukariew&ndash, Priklonski classification. Knowledge of the distribution and chemical compositions of springs is essential for a good hydrological and hydrogeological understanding of a given area. In previous decades, underground water remained mostly uncontaminated, and the ions used in the Szczukariew&ndash, Priklonski classification, namely, Na+, Mg2+, Ca2+, Cl&minus, SO42&minus, and HCO3&minus, provided accurate descriptions of this water. However, due to anthropogenic activity in the last decades, NO3&minus, and NH4+ ions in shares greater than 20% have been frequently noted in underground and spring water. Research has been conducted in two forested regions: within the Skrzyczne range, which is under pressure from high air pollution coming from the Ostrava and Upper Silesia industrial districts, and in Gorce National Park, which is impacted by low-level air pollution. Water samples were collected three times per year in 2011 and 2012 at various water levels after a spring snow thaw, a period of heavy rain and a dry period. A search for the following ions was conducted: Ca2+, Mg2+, Na+, K+, NH4+, HCO3&minus, Cl&minus, and NO3&minus, Under the Szczukariew&ndash, Priklonski classification system, due to the continuous accumulation of nitrogen compounds from air pollution, the shares of nitrates and ammonium ions in underground water and spring water are likely to increase.

Surface water is the principal source of water for domestic use and agricultural irrigation in Grouz Dam Basin and adjacent regions. This research aims to evaluate hydrochemical characteristics and suitability for domestic and agricultural irrigation purposes of the Grouz Dam Basin surface waters. The surface waters were categorized as alkaline hard freshwater and are classified into Na-Cl and mixed water types. The values of measured parameters are below the maximum allowable limits for drinking except for Na+, NO32- and turbidity. Dissolution and anthropogenic activity are the dominant hydrogeochemical processes controlled surface water chemistry. Overall, it was found that surface waters are unsuitable for drinking by cons they are suitable for irrigation. The results of this study will be useful in regional surface water management and protection.

Connectivity of groundwater flow within crystalline-rock aquifers controls the sustainability of abstraction and baseflow to rivers, yet is often poorly constrained at a catchment scale. Here groundwater connectivity in a sheared gneiss aquifer is investigated by studying the intensively abstracted Berambadi catchment (84 km2) in the Cauvery River Basin, southern India, with geological characterisation, aquifer properties testing, hydrograph analysis, hydrochemical tracers and a numerical groundwater flow model. The study indicates a well-connected system, both laterally and vertically, that has evolved with high abstraction from a laterally to a vertically dominated flow system. Likely as a result of shearing, a high degree of lateral connectivity remains at low groundwater levels. Because of their low storage and logarithmic reduction in hydraulic conductivity with depth, crystalline-rock aquifers in environments such as this, with high abstraction and variable seasonal recharge, constitute a highly variable water resource, meaning farmers must adapt to varying water availability. Importantly, this study indicates that abstraction is reducing baseflow to the river, which, if also occurring in other similar catchments, will have implications downstream in the Cauvery River Basin.

Jinan is known as &ldquo, Spring City,&rdquo, because of its famous 72 artesian springs. Spring water plays an important role in the social and economic development of Jinan. However, the accelerating process of urbanization and more intensive human activities have significantly affected the Jinan springs. Based on the data from four spring groups (2015&ndash, 2018), the hydrochemical characteristics of spring water were analyzed and 14 parameters were selected to evaluate the quality of spring water. In addition, the main ions variation characteristics of spring water in Jinan from 1958 to 2018 were analyzed, based on the previous studies. Subsequently, the spring flow dynamics of the Jinan spring area from 1958 to 2012 were also discussed. Overall, the water quality of the four spring groups is good. The chemical composition of the spring water is mainly controlled by the dissolution of calcite, followed by dolomite, and de-dolomitization. However, spring water is affected by human activities, and the hydrochemical type tends to evolve from HCO3-Ca to HCO3&middot, SO4-Ca or HCO3-Ca&middot, Mg. From 1958 to 2013, the main ions in spring water increased, while a relatively steady and certain fluctuation trend was observed from 2015 to 2018. Since 1958, the spring water flow in Jinan has experienced four stages, from decline to recovery. The exploitation of karst groundwater, change of land use type, and decrease of atmospheric precipitation are the three most important factors, affecting spring discharge dynamics. The slowdown of the increase of the main ion concentration in Jinan spring water and the resumption of spring water flowing indicate that remarkable achievements have been made to protect spring water, but there is still a long way to go to fully protect Jinan spring water.

The major springs in the Infranz catchment are a significant source of water for Bahir Dar City and nearby villages, while sustaining the Infranz River and the downstream wetlands. The aim of the research was to understand the hydrogeological conditions of these high-discharge springs and the recharge&ndash, discharge relations in the Infranz catchment. The Infranz catchment is covered by highly pervious and young quaternary volcanic rocks, consisting of blocky, fractured, and strongly vesicular scoriaceous basalt. At the surface, these rocks crop out as lineaments forming ridges, delimiting closed depressions in which water accumulates during the rainy season without causing surface runoff. Geology and geomorphology thus combine to produce very favorable conditions for groundwater recharge. Three groundwater recharge methods were applied to estimate groundwater recharge and the results were compared. Groundwater recharge was calculated to be 30% to 51% of rainfall. Rapid replenishment raises the groundwater level during the rainfall period, followed by a rapid decline during the dry season. Shallow local flow paths discharge at seasonal springs and streams, while more regional and deeper flow systems downstream sustain the high-discharge springs and perennial Infranz River. The uptake of 75% of spring water for the water supply of Bahir Dar City, local extraction for domestic and small-scale irrigation use from springs, rivers and hand-dug wells, encroaching farming, and overgrazing are exacerbating wetland degradation.

The paper presents the results of a comprehensive assessment of the current ecological state of the important recreational object, i.e. Lake Manzherokskoye (Maiminsky region of the Altai Republic, the Russian Federation). The investigation was conducted in August 2018, just 2 weeks after the dredging works implemented in the framework of the environmental rehabilitation project. The studied morphometric, hydro/physical and hydro/chemical parameters of the reservoir are evidence of an increase in lake depth (with its maximum more than 2 m, up to 5.66 m) and water volume (more than 2 times, up to 1,16 million m3) that in the future will lead to the improved oxygen regime and the decreased inflow of biogenic matter. Bottom sediments are still represented by soils with a high content of organic carbon (up to 56,2±2.9 mg/dm3) and organic matter (up to 112.3±10,2 mg/dm3); detritus and organic silt (sapropel) dominate in the sediments. In all studied sites and depths of Lake Manzherokskoye, the water was polluted by roiled organic silts. The concentration of suspended solids reached 4.6 g/dm3, whereas transparency (by Secchi disk) dropped up to 0,5 cm. Vertical distribution of suspended substances points to the process of their deposition. Water quality of the lake is estimated as unsatisfactory because of the performed dredging works. Major pollutants of the lake water are phosphates (up to 0,417±0,042 mg/dm3), petroleum products (up to 0,4±0,1 mg/dm3) and organic substances (up to 342,2±35,8 mg O/dm3 by unfiltered water COD); their concentrations exceed MAC significantly. Water quality does not meet the requirements imposed upon the water bodies used for recreational purposes.

The Sidi Bouzid and El Hjal Wadi basins together comprise one of the most important agricultural regions in Central Tunisia. Exploitation of the groundwater in this region is increasing exponentially. In this work, hydrochemical characteristics and the analytic hierarchy process (AHP) were used to assess the suitability of the groundwater in the aquifer for use in irrigation. Concentrations of total dissolved solids in the groundwater ranged from 1500 to 5000 mg/L. The most abundant chemical species in the water were SO42− and Cl−, with mean concentrations of 1010 mg/L and 641 mg/L, respectively. The high levels of these species can be explained by sulfate mineral dissolution and the leaching of evaporitic formations into the groundwater flow. Quality criteria weighting using the AHP was employed to generate a map of groundwater suitability for irrigation. This method categorized water samples as either excellent, good, or permissible for irrigation based on the Water Quality Index (WQI). Most of the water samples (76.5%) in the study area were found to contain water that would be good for irrigation, although the groundwater quality deteriorated towards the areas with low elevation.

Urban karst aquifers are threatened by anthropogenic activities, especially in semiarid developing countries. Recent water-sampling campaigns assessed the extent of groundwater-quality impairment in the Wadi Shueib in Jordan by a comprehensive hydrogeological and hydrochemical characterization of groundwater, wastewater, and imported water with its endmembers Lake Tiberias, Yarmouk River and Mukheiba wellfield. The results of a ternary mixing model with the mass ratios of Cl−/Br− and Ca2+/Mg2+ indicate that Lake Tiberias and Yarmouk River provide most of the imported water at the time of sampling in 2017 and Mukheiba wellfield provided minor amounts. The similarity in seasonal variations of Br− concentrations in the springs and the imported water revealed that imported water has generally a greater impact on groundwater than wastewater. However, the Br− concentrations also showed that the spatial wastewater impact is more visible towards urbanized areas due to increased infiltration of pollutants. The analysis of historical data series demonstrated the long-term urban impact on groundwater by an electrical conductivity increase over several decades, particularly since the mid-1990s, which is related to a doubling of Jordan’s population since that time and the associated urban growth. In this context, increased chloride and sulfate concentrations are noticeable due to the increased impact of more highly mineralized imported water and wastewater and decreasing recharge of low-mineralized rainwater. This study showed the hydrochemical differences in the Wadi Shueib groundwater system and serves as an example for the spatial and long-term response of karst aquifers to anthropogenic, seasonally variable input of imported water and wastewater., The Federal Ministry of Education and Research (BMBF)

The effects of an extreme storm (501 mm of rainfall in less than five days) were monitored in an alpine show cave to assess the characteristics of its aquifer unsaturated and saturated zones. The selected cave, Bossea (SW Piedmont, Italy), is an excellent test site for hydrological investigation of karst systems, because it hosts an underground karst laboratory since the late 70 s. The investigation was carried out by means of an integrated approach that combined measurements of flow discharge, physico-chemical parameters, major chemical components, and trace elements (metals, Rb, Ba, Sr and REE). The hydrology and hydrochemistry of the main underground river and two of its secondary tributaries (a drip site and a small secondary inflow) draining the unsaturated zone were monitored during the November 2016 flood, an exceptional hydrological event (estimated recurrence time of 200 years) that caused severe damages in the whole southwestern Piedmont region. The results of the 2016 monitoring were compared with those of another less extreme flood occurred in 2011 (recurrence time of 20 years). The karst system showed an impulsive response to flooding at the catchment and at the individual inflow scales, but each site exhibited a characteristic response due to the complex geological and structural setting of the cave system. The development of this karst system is, in fact, related to the lateral and vertical juxtaposition of rocks with different lithologies and mechanical properties, which form different hydrogeologic compartments. Coupling hydrograph, chemograph analysis and REE normalized patterns permitted to assess which compartments were activated during each phase of the floods. In particular, it was possible to recognize a progressive increasing contribution of the non-carbonate lithologies to flow during the peak of the flood for both the two unsaturated inflows and the main underground river, suggesting the activation of larger portions of the aquifer. However, the response of each individual unsaturated inflow is more influenced by its recharge system architecture rather than the magnitude of the meteorological event. Similar complex geological and lithological karst systems are typical of many areas characterized by orogenetic processes (Alps, Rocky Mountains, Caledonides, etc.), but despite them being relatively widespread, the hydrodynamics of these aquifers is still poorly understood. This study affirms that only long-term and well-integrated monitoring and sampling can help unravel the behavior of such complex karst systems.

Groundwater nitrate (NO3−) pollution sources and in situ attenuation were investigated in Kisumu city and Kano plains. Samples from 62 groundwater wells consisting of shallow wells (hand dug, depth &lt, 10 m) and boreholes (machine drilled, depth &gt, 15 m) were obtained during wet (May–July 2017) and dry (February 2018) seasons and analyzed for physicochemical and isotopic (δ15N-NO3−, δ18O-NO3−, and δ11B) parameters. Groundwater NO3− concentrations ranged from &lt, 0.04 to 90.6 mg L−1. Boreholes in Ahero town showed significantly higher NO3− (20.0–70.0 mg L−1) than boreholes in the Kano plains (&lt, 10.0 mg L−1). Shallow wells in Kisumu gave significantly higher NO3− (11.4–90.6 mg L−1) than those in the Kano plains (&lt, 10.0 mg L−1). About 63% of the boreholes and 75% of the shallow wells exceeded the drinking water WHO threshold for NO3− and NO2− (nitrite) during the study period. Mean δ15N-NO3− values of 14.8‰ ± 7.0‰ and 20.7‰ ± 11.1‰, and δ18O-NO3− values of 10.2‰ ± 5.2‰ and 13.2‰ ± 6.0‰ in wet and dry seasons, respectively, indicated manure and/or sewage as main sources of groundwater NO3−. However, a concurrent enrichment of δ15N and δ18O was observed, especially in the dry season, with a corresponding NO3− decrease, indicating in situ denitrification. In addition, partial nitrification of mostly sewage derived NH4+ appeared to be responsible for increased NO2− concentrations observed in the dry season. Specifically, targeted δ11B data indicated that sewage was the main source of groundwater NO3− pollution in shallow wells within Kisumu informal settlements, boreholes in Ahero, and public institutions in populated neighborhoods of Kano, while manure was the main source of NO3− in boreholes and shallow wells in the Kano and planned estates around Kisumu. Waste-water sanitation systems in the region should be urgently improved to avoid further deterioration of groundwater sources.

Quality assessment of groundwater for drinking and irrigation was evaluated in parts of Nalgonda district of Telangana state, India. The overall groundwater quality and the suitability to drinking and irrigation were evaluated by hydrochemical analysis of 78 groundwater samples. The water quality parameters were compared with that of the limits set by World Health Organisation (WHO) and Bureau of Indian Standards (BIS). Groundwater is found to be contaminated by fluoride and nitrate ions. The water quality indices (WQI) suggest that during pre-monsoon, 72.5% samples are suitable for drinking while 86.8% are suitable during post-monsoon. Indicators like sodium absorption ratio (SAR), electrical conductivity (EC), percent of sodium (Na %), residual sodium carbonate (RSC), permeability index (PI), magnesium ratio (MR), residual sodium bicarbonate (RSBC), salinity hazard (SH), potential salinity (PS), soluble sodium percentage (SSP), and magnesium ratio (MR) were estimated for assessing the irrigation suitability of the groundwater samples. Wilcox, United States Salinity Laboratory diagrams (USSL diagram) and Doneen’s chart infer that most of the samples are suitable for irrigation purpose and the suitability improves during post-monsoon. The geochemical evolution of the groundwater was also studied using Piper’s and Chadha’s diagrams. The major facies found in groundwater are Na–Mg–HCO3–Cl, Na–Mg–HCO3, Na–HCO3, Mg–Ca–HCO3, Mg–Na–HCO3 and Na–Cl. Rock-water interaction, ion exchange and evaporite dissolution were found to be the major geochemical processes governing the groundwater chemistry.

A characteristic feature of the mines in the Upper Silesian Coal Basin in southern Poland is their highly saline mine water. In the past, this water was often discharged into anthropogenic reservoirs located a short distance from the mines, which completely changed the physicochemical properties of the water. In some cases, it also led to stratification of the reservoir waters, i.e. to the formation of meromictic water bodies. The Rontok Wielki reservoir, a former fish breeding pond, was converted into a settling tank for the highly saline ( Cl− = 38,000 mg/L) water discharging from the Silesia Mine. The water in the tank stratified in three distinct zones: a mixolimnion, chemocline, and monolimnion. The saline mine water input ceased in 2003 and since then, there has been a gradual decrease in the electrical conductivity and [ Cl−] in the reservoir waters. Moreover, meromixis has been entirely eliminated and freshwater breeding species have reappeared. A control, the Rontok reservoir, which was also a breeding pond, but was never used to settle saline mine water, was also studied for comparison.

Study region: The Turonian-Coniacian aquifer system in the North of the Coastal Sedimentary Basin, southern Benin, West Africa. Study focus: The Turonian-Coniacian aquifer is the major aquifer in southern Benin and is the main source of water supply for the population. The pressure on groundwater resources from the Turonian-Coniacian aquifer is increasing since few artesian wells tapping into this aquifer already show decrease in their yields. Preventing extinction of the artesian outflows requires as a first step a thorough understanding of the groundwater flow system: groundwater recharge areas, downstream areas, and flow directions. In this study, a combined hydrogeological, hydrochemical and isotopic approach was applied to understand the groundwater flow within this aquifer and to develop a coherent conceptual groundwater flow model. New hydrological insights for the region: The piezometric results indicated three main groundwater flow directions. Stable isotopes results confirmed the piezometry as the most depleted and enriched values in Oxygen-18 and deuterium were found respectively in downstream areas (southern region) and in the recharge areas (northern region) indicated by the piezometry. Similarly, higher tritium contents (up to 3.5 Tritium Unit) characterize recharge areas and low tritium contents (

Study Region Noseongcheon catchment is a mesoscale agricultural basin with crystalline bedrocks with seasonally variable precipitation and groundwater use. Study Focus This study aimed to assess the influence of headwater streams on streamflow across the stream network in the study area under the temperate monsoonal climate conditions. Using hydrochemical parameters and stable isotopes in stream water and groundwater in the dry and rainy seasons, the water sources contributing to the stream network were identified and the seasonal changes in the streamflow system were evaluated. New Hydrological Insights for the Region Seasonal variations of hydrochemical parameters and water stable isotopes indicated that the contributions of major water sources to streamflow in the catchment changed according to the seasonal precipitation pattern. Groundwater affected by agricultural activities discharges into the stream at the piedmont area from mountain to plain, irrespective of season. However, the contribution of uncontaminated mountain bedrock discharge (MBD) showed a marked difference between dry season and rainy season. The contribution of MBD ranged from 20% to 75% in the dry season, while it increased up to 90% in the rainy season. These results indicate that the responses of mountainous area to precipitation in the rainy season is a major factor affecting the hydrological functioning of the whole stream network.

The investigation of groundwater quality is one of the most important subjects in the field of groundwater resource. The main purpose of this research is the study of groundwater samples witch have been collected from 12 and 9 pumping wells throughout 1385-1394 years. The samples have been analyzed for major cations (Na, K, Mg and Ca), major anions (Cl, SO4, HCO3 andCO3) and physical parameters such as TDS, TH, Ec and pH. In following, the hydrogeochemical graphs such as Piper diagrams used for water classification. The analysis of results showed the increasing of TDS, TH and EC upper the limit. According to Schoeller and Wilcox diagrams, the water is not suitable for drinking purposes, agricultural and industrial uses. Such results are more helpful to manage the groundwater resource.