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In this review, we explore the concept, approach, and future research of hydrological connectivity and its assessment at multiscales, because according to the literature, an integrated review upon hydrological connectivity is lack. Systematic studies illustrate the effects of (i) human activities (i.e., dam construction, groundwater extraction, water flow regulation and diversion, and land management) and (ii) natural factors (i.e., climate, soil characteristics, vegetation, and topography) on hydrological connectivity. Approaches (i.e., soil water content patterns, runoff patterns and processes, numerical models, and index of hydrological connectivity) applied to evaluate hydrological connectivity are examined in detail. Lastly, hydrological connectivity at multiscales is indicated. This review concludes with a discussion of potential research trends that can improve understanding of hydrological connectivity. Reported records showed that few studies were published on hydrological connectivity from 1980 to 2003, whereas the evolution of these studies is temporally promising since 2003. We cannot define a standard concept of hydrological connectivity that works in all environments. We desire to show different concepts of hydrological connectivity in different environments. The degree and nature of hydrological connectivity are not static due to the influences of human activities and changes of natural factors. The index of hydrological connectivity and numerical models are the most significant approaches to assess the changes in hydrological connectivity. This study showed that considering hydrological connectivity in social-economical-ecological-hydrological frameworks can prevent its negative effects on surface or subsurface water quantity and quality and is beneficial for sound water sources management.

Empresas e demais entes com personalidade jurídica responsáveis pelo tratamento e abastecimento de água se concentram nos centros urbanos, não atingindo a zona rural, salvo por exceções em localidade onde a expansão urbana já margeia a zona rural. Considerando este fato, a população rural acaba por se utilizar de fontes alternativas, captando a água bruta, que fica sujeita a toda sorte de contaminantes, seja por ação antrópica ou por ocorrências naturais. O presente trabalho tem como objetivo avaliar o parâmetro turbidez da água direcionada ao consumo de empregados em estabelecimentos rurais e indicar a tecnologia de tratamento de água mais simples que se amoldaria a melhorar a qualidade de água com base nos valores observados de turbidez nas análises laboratoriais realizadas. A pesquisa teve como população-alvo empregados rurais que se utilizam da água disponível em estabelecimentos com mais de dez empregados, situados no município de Três Corações/MG. Os levantamentos abrangeram três etapas: a primeira, de contato e autorizações concedidas pelos empregadores ou responsáveis pelos estabelecimentos rurais; a segunda de levantamento de dados dos locais de captação com verificação do número de indivíduos abastecidos pela água e a terceira, de realização de coleta das amostras de água e encaminhamento para laboratório acreditado. Nos locais de captação elegidos foi realizada coleta para análise da água, abrangendo o parâmetro turbidez. As avaliações abarcaram dezesseis locais de captação, distribuídos no interior de oito estabelecimentos rurais, todas captações de água subterrâneas e subsuperficiais, não havendo nenhuma em manancial superficial. Da população de empregados abrangida na pesquisa, 82,00% eram do sexo masculino e 17,00% do sexo feminino, todos maiores de idade e 26,72% residiam nos estabelecimentos rurais distribuídos em 48 edificações fornecidas pelos empregadores. As análises do parâmetro proposto demonstraram que a qualidade da água bruta captada nos estabelecimentos rurais mantinha níveis numéricos de turbidez que possibilitaria a submissão direta a processo de desinfecção em 75 % das amostras e os outros 25 % seriam passíveis de tratamento por processos simplificados de forma a melhorar sua qualidade.

Dijil River catchment is a sub-catchment of the Abay drainage basin and covers 138.28 km2. This paper presents numerical groundwater flow modeling at steady-state conditions, in a single-layer aquifer system under different stress or scenarios. A numerical groundwater flow models represent the simplification of complex natural systems, different parameters were assembled into a conceptual model to represent the complex natural system in a simplified form. The conceptual model was input into the numeric model to examine the system response. Based on geologic and hydrogeological information, confined subsurface flow condition was considered and simulated using MODFLOW 2000. The model calibration accounts matching of 24 observation points with the simulated head with a permissible residual head of ±10m. The sensitivity of the major parameters of the model was identified during the calibration process. According to the simulated water budget in the model, the simulated inflow is found to be 1.2791870E+05 m3/day which is nearly equal to the simulated outflow of 1.2791755E+05 m3/day with the difference being only 1.1484375E+00 m3/day. Water budget analysis reveals that outflow from river leakage accounts for 92.8 % of the total outflow and 14.1 % of the total inflow comes from the river leakage in the study area. Three scenarios of increased withdrawals and one scenario of altered recharge were used to study the system response. Accordingly, an increase in well withdrawal in scenario-I (existing wells pump simultaneously), scenario-II (existing drilled wells yield withdrawal increased by 30%), and scenario-III (additional eight wells having expected yield of 30 l/s drill and pump) resulted in an average decline of the steady-state water level by 1.06m, 1.68m, and 4.46m, respectively. They also caused the steady-state stream leakage to be reduced by about 2.93%, 4.58%, and 11.23%, and subsurface outflow by 9.41%, 14.67%, and 37.86%, respectively. A decrease in recharge by 25% and 50% results in a decrease of the head by 6.1m and 13.4m respectively, and a stream leakage decrease by 20.3%, and 40.3% respectively as compared to the simulated steady-state value. Therefore, adequate groundwater level monitoring wells should be placed in the catchment to control the total abstraction rates from the aquifer and fluctuations in groundwater levels.

The water body inside the constructed wetland is affected by various factors, and the flow state is relatively complicated. There will always be a certain degree of low velocity area and rapid outflow phenomenon, which makes part of the space in the wetland unable to be effectively used. Based on Computational Fluid Dynamics (CFD) technology, this paper uses Fluent's porous media model and discrete phase model to establish a hydrodynamic model of up and down baffled subsurface flow constructed wetland system. The internal flow field of the wetland is simulated, and the hydraulic performance of different baffle settings and substrate laying methods in the wetland is systematically evaluated. The results show that when the number of baffles is the same, the hydraulic efficiency is higher when the first baffle is located on the lower part of the substrate. Compared with the position of the baffle, the increase in the number of baffles does not significantly improve the hydraulic efficiency of the constructed wetland. The substrate layer thickness ratio has a significant effect on the two parameters of the variance of the hydraulic residence time distribution (σ2) and the flow divergence (σ02). By increasing the thickness of the middle substrate, the low flow rate phenomenon caused by the small porosity substrate area of the upper layer and the rapid outflow phenomenon of the lower substrate can be improved to a certain extent, the utilization efficiency of the middle substrate layer is improved, and the hydraulic performance is increased. The research results are of great significance for improving the utilization of wetland space and ensuring its efficient decontamination and purification function. HIGHLIGHTS The hydraulic performance of constructed wetland is affected by baffle setting and substrate laying.; The first baffle is located at the lower part of the substrate with higher hydraulic efficiency.; The layer thickness ratio of the substrate mainly affects the hydraulic residence time distribution and the flow divergence.

Groundwater is a valuable natural resource whose quality is threatened by natural and man-made pollutants. This study aims to perform a hydrochemical characterization of groundwater resources used for domestic and irrigational activities in Melong (Littoral Cameroon). Thus, 26 subsurface water samples were collected in the dry season (six sampling points) and rainy season (seven sampling points) of the years 2019 and 2020. Physical water quality parameters were measured on the field while ionic constituents and bacteriological parameters were determined in the laboratory. The main findings revealed that the pH of the water samples was slightly acidic to neutral, fluctuating from 5.3 to 7.1; electrical conductivity ranged from 0.03 to 0.33 µS/cm and turbidity varied from 0.5 to 33.7 NTU revealing that the water is weakly mineralized. The ionic constituents were such that Ca2+ > K+ > Mg2+ > Na+ for cationic constituents while anions appeared as HCO3-> NO3- >Cl- > PO43-. The major ions fell within the acceptable limits of World Health Organisation (WHO) drinking water standards. Bacteria indicators of faecal pollution were identified in all the water samples, including Enterobacteria, Escherichia coli, Streptococcus, Salmonella, Shigella, Staphylococcus and Vibrio. This indicates an exposure of water sources to unhygienic conditions that may place consumers at risk of water-borne diseases, hence necessitating basic treatment of the water before consumption. Key words: Hydrochemistry, Melong, groundwater quality, bacteriological analysis, Littoral Cameroon.

Recent observations and numerical simulations have profoundly established that the C:N:P ratios in the ocean deviate from the canonical Redfield Ratio (106:16:1). Physical and biogeochemical processes have been hypothesized to be responsible for this deviation. However, a paucity of concurrent observations on biogeochemical and physical parameters have barred us to understand their exact role on the C:N:P ratios. For this purpose, we have sampled the Bay of Bengal for its C, N, and P contents in the organic and inorganic pools from 5 to 2000 m depth at eight stations (five coastal and three open ocean) during boreal spring 2019. Mesoscale anticyclonic eddies were identified at two of the sampling stations, where nutrient concentrations were lower in the top layer (5 m to the depth of chlorophyll maximum) compared to those at the non-eddy stations. Mean (NO3−+NO2−):PO43− ratio was lower at the anticyclonic eddy stations compared to that at the non-eddy stations in the top layer. Yet C:N:P ratios in the particulate and dissolved organic matter in the top layer were the same at anticyclonic eddy and non-eddy stations. Overall the mean C:N:P ratios were 249:39:1 in particulate organic matter and 2338:146:1 in dissolved organic matter in the top layer. Biological N2 fixation was not a driver in controlling the N:P ratio of the export flux and the subsurface water nutrient ratios during spring. Although the Bay of Bengal receives large riverine influx, its influence in changing the C:N:P ratios was small during this study.

The operation of stationary soil lysimeters is largely determined by the areal and vertical limitations of the soil mass. The areal spatial limitations of large lysimeters operating at the Moscow State University Soil Station and the proximity of phytocoenoses developing in them to each other contribute to the additional transport of plant litterfall by wind, while the vertical limitations eliminate the role of groundwaters and their soil-forming effects. The absence of lateral subsurface flow that is typical for natural landscapes and the increased inflow of alkaline-earth elements with atmospheric precipitation and dust reduce the manifestation of the eluvial–illuvial process. Comparative analysis of lysimetric waters in 1967–1968 and in 2014–2015 shows a significant increase in concentrations of such cations as calcium, sodium, magnesium, and potassium and such anions as chloride and sulfate over this period. The local spatial geochemical contrast of lysimetric waters caused by the impact of deicing agents does not affect the relative migration capacity of elements. Based on their biogeochemical accumulation levels in the soil, macroelements form the following series Ca > K > Al > Mg > N; microelements: Zn > Sr > Cu > Ba. The above patterns persist in all types of lysimeters. The calcium concentration in soils increases in the series: broadleaf forest > mixed forest > spruce forest > black fallow. The increased accumulation of elements in soils of spruce forests correlates with the humus type (moder-like) formed under them; this humus type is determined by the combination of coniferous and deciduous litterfall.

Subarctic peatlands underlain by permafrost contain significant amounts of organic carbon. Our ability to quantify the evolution of such permafrost landscapes in numerical models is critical for providing robust predictions of the environmental and climatic changes to come. Yet, the accuracy of large-scale predictions has so far been hampered by small-scale physical processes that create a high spatial variability of thermal surface conditions, affecting the ground thermal regime and thus permafrost degradation patterns. In this regard, a better understanding of the small-scale interplay between microtopography and lateral fluxes of heat, water and snow can be achieved by field monitoring and process-based numerical modeling. Here, we quantify the topographic changes of the Šuoššjávri peat plateau (northern Norway) over a three-year period using drone-based repeat high-resolution photogrammetry. Our results show thermokarst degradation is concentrated on the edges of the plateau, representing 77 % of observed subsidence, while most of the inner plateau surface exhibits no detectable subsidence. Based on detailed investigation of eight zones of the plateau edge, we show that this edge degradation corresponds to an annual volume change of 0.13±0.07 m3 yr−1 per meter of retreating edge (orthogonal to the retreat direction). Using the CryoGrid3 land surface model, we show that these degradation patterns can be reproduced in a modeling framework that implements lateral redistribution of snow, subsurface water and heat, as well as ground subsidence due to melting of excess ice. By performing a sensitivity test for snow depths on the plateau under steady-state climate forcing, we obtain a threshold behavior for the start of edge degradation. Small snow depth variations (from 0 to 30 cm) result in highly different degradation behavior, from stability to fast degradation. For plateau snow depths in the range of field measurements, the simulated annual volume changes are broadly in agreement with the results of the drone survey. As snow depths are clearly correlated with ground surface temperatures, our results indicate that the approach can potentially be used to simulate climate-driven dynamics of edge degradation observed at our study site and other peat plateaus worldwide. Thus, the model approach represents a first step towards simulating climate-driven landscape development through thermokarst in permafrost peatlands.

Microgels are plankton-derived transparent exopolymer particles (TEP) and have a significant impact on global marine carbon cycle. We investigated the influence of biogeochemical variables on the pattern of TEP abundance and its associated carbon (TEPC) distribution through a vertical transect of the northern South China Sea (nSCS) during summer, 2014. The average TEP concentration was 58.32±30.56 μg Xeq./L. Vertically, it was higher in the subsurface water column and lower at 200-m water depths. As chlorophyll a (chl a), TEP, and TEPC were highly concentrated at the bottom of the study transect, mainly on the continental shelf bottom and slope regions. Among biotic factors, cyanobacteria, especially Trichodesmium thiebautii showed significant positive correspondences with TEP through studied water columns in nSCS. In addition, TEP showed a positive correlation with chl-a distribution and clustered closely with diatom as well. It indicates a combined contribution of them on TEP sourcing accordingly. Nutrient concentrations were also high due to estuarine diluted water from Zhujiang (Pearl) River in the season that may intrigue those scenarios. Significant positive correlation (P < 0.05) among biotic and abiotic parameters also supported the statement. Furthermore, mentionable contribution of TEP-derived TEPC was found after comparing the particulate organic carbon data, which may signify the importance of TEP in local carbon cycle in the nSCS.

Assessment of groundwater quality is vital to protect this natural resource. The aims of this study were to evaluate the hydrochemical quality and deciphering its suitability for irrigation and human consumption purposes from the Saltora block of Bankura district, West Bengal. The district is characterized by adequate annual precipitation, but many parts of this district are facing acute water crisis. This may be due to its geological setup which is not suitable and also because of the presence of impervious lithology near to subsurface and also because of inundated nature of surface drainage pattern. Groundwater samples from 16 bore wells have been collected covering the entire block, during two sampling sessions—pre- and post-monsoon sessions of the year 2019 to have a present status on concentration and spatiotemporal fluctuations of controlling ions of the subsurface water. Measurements of some physicochemical parameters have been carried out in spot by Hanna Instruments and other qualitative chemical characteristics of groundwater were analyzed in laboratory. Measurements of different parameters such as sodium adsorption ratio, magnesium adsorption ratio (MAR), soluble sodium percentage, residual sodium carbonate, permeability index (PI), total hardness (TH), Kelly’s ratio (KR) and Piper trilinear plots followed by Gibb’s diagram and Schoeller diagram have been carried out for deciphering drinking, domestic and irrigation suitability of the Saltora block water. Gibb’s diagram indicates that general groundwater chemistry is dominated by the natural process of rock water interaction. Charge balance of groundwater samples collected seem to be good based upon the Ionic balance calculations. Schoeller diagram results present the following trends: Ca2+ > Mg+ > Na+ > K+; HCO3¯ > Cl¯ > SO42¯ > total Fe > F (for mg/L) and Mg+ > Ca2+ > Na+ > K+; Cl¯ > HCO3¯ > SO42¯ > F (for meq/L). High values of magnesium in around 60–70% of the samples have resulted in high MAR values (> 50) depicting increase in its alkaline nature. The Piper diagram results show that all groundwater samples collected from the investigated area do not conform to the fresh water category and therefore are not deemed suitable for drinking purposes. Water quality index values varied from 32.96 to 518.08 in pre-monsoon and 36.77 to 190.23 in post-monsoon sessions which indicate that the water of this block is good enough to use for domestic purposes. High to very high iron content in groundwater is observed across both sampling sessions in the study area. Thus, removal of iron through alum treatment of the groundwater seems to be the only cost-effective and reliable method to turn the groundwater completely potable in the study area.

Despite its location in the “Arid Diagonal” of South America, the Valle de Iglesia contains a number of artesian springs, the most important of which are the Baños Pismanta thermal springs, which release water at ~ 45 °C. Despite the scarcity of water resources in the Valle de Iglesia, there have been few attempts to study these springs in any detail. In this study, > 50 springs are described, each characterised by small volcano-like mud structures up to 15 m tall. Hydrogeological and hydrochemical analyses of the groundwater system in the Valle de Iglesia were performed to improve our understanding of the subsurface water flow and of the connections between the subsurface water and the associated systems of faults and springs. Site measurements were made, and the concentrations of the main ions and trace elements were also determined by laboratory analysis of water samples. The samples obtained from the spring were rich in Na–HCO3–SO4 and Na–SO4–HCO3, but the surface water samples from the Agua Negra River were rich in Ca–SO4–HCO3. The temperature of the springs was in the range 20–45 °C. Both the temperatures and the ionic ratios are compatible with the presence of a deep hydraulic circulation system. The oxidation of sulphide minerals nearby the magmatic rocks and volcanic edifices causes the mobilisation of arsenic, which accumulates in the groundwater due to the low annual rainfall. The concentrations of arsenic in the spring water samples were therefore higher than the current limit set by the World Health Organisation, meaning that the water is not suitable for human consumption.

Coastal reservoirs can alleviate freshwater shortages occurring in the nearshore zone. Deep pools patched at the bottom of reservoirs at greater depths than their adjacent beds maintain a high salinity and possibly provide preferential paths for saltwater backfill. However, such processes are not well understood. Laboratory experiments and numerical simulations were conducted to investigate the effect of the deep pool on subsurface flow and the salinization of coastal reservoir and adjacent aquifers. When seawater intruded into the initially fresh aquifer, the deep pool accelerated the uptake of saltwater to the reservoir from the salt wedge, forming a temporary salt plume around the pool. The saltwater plume also accelerated salt ingress and the evolution of the total salt mass in the coastal reservoir, resulting in the earlier attainment of a quasi-steady state (a classical saltwater wedge) than that when the deep pool was absent. Under steady-state conditions, the deep pool greatly enhanced the exchange of water across the reservoir-aquifer interface by 107% and raised the salinization level of the coastal reservoir by at least 10.3%. Sensitivity analysis suggested that a deeper pool and/or a pool located closer to the reservoir dam may enhance the water exchange and salinity level in the reservoir because it accelerates the water/salt inflow to the freshwater body to a greater extent. These findings may further contribute to improving the predictability and management of water quality in these coastal facilities.

Environmental monitoring indicators guide the decision-making process of public policies. Bioassays using seeds are a potential tool to evaluate water quality indicators, since their results can be expressed in a phytotoxicity scale, the tests are quite simple, relatively fast, and low cost. In this context, the objectives of this study were to evaluate the phytotoxicity of Rio Grande reservoir waters and its relationship with environmental variables. In Brazil, this reservoir is an important water source for the public supply of the Metropolitan Region of São Paulo. In 2018, subsurface and bottom water were collected in four sampling campaigns. The environmental variables were measured both in field and at the laboratory. In field, it was used a multiprobe of ammonium (N-NH4+), electrical conductivity (EC), nitrate (N-NO3-), pH, dissolved oxygen (DO) and water temperature (T); and, at the laboratory, of total nitrogen (TN) and total phosphorus (TP). Bioassays using seeds of cucumber (Cucumis sativus), garden cress (Lepidium sativum), and mustard (Sinapis alba) were performed (n = 6). The bioassays consisted of incubating the seeds and the water samples on Petri dishes at (20º ± 2 ºC) in the absence of light for 3 days, in case of S. alba, and for 4 days, in case of C. sativus and L. sativum. ISO water was used as a control. Afterward, the number of germinated seeds and the roots' length were determined to calculate the Germination Index (GI). Statistical analyses were performed, such as the Shapiro-Wilk test, the analysis of variance (ANOVA) and the Tukey test, to verify the differences between the seeds' responses to the environmental variables. The Principal Component Analysis (PCA) was applied to the environmental variables and the GI to identify the most representative variables. This study indicated that, in May of 2018, the subsurface water was moderately phytotoxic to L. sativum (GI = 61.3 ± 8.2%); and the bottom water was very phytotoxic to L. sativum (GI = 23.6 ± 14.5%) and S. alba (26.2 ± 12.0%). In all other sampling campaigns, the water samples potentiated seed germination, which can be related to nutrients concentrations The L. sativum proved to be more sensitive, due to the lower degrees of data dispersion and the higher degrees of toxicity when compared to the other analysed seeds. Os indicadores de monitoramento ambiental norteiam o processo de tomada de decisão de políticas públicas. Bioensaios com sementes são ferramentas potenciais como indicadores de qualidade da água, pois seus resultados podem ser expressos em uma escala de fitotoxicidade, os testes são bastante simples, relativamente rápidos e de baixo custo. Nesse contexto, os objetivos deste estudo foram: avaliar a fitotoxicidade das águas do reservatório do Rio Grande e sua relação com as variáveis ambientais. Este reservatório é uma importante fonte de água para a Região Metropolitana de São Paulo no Brasil. Água subsuperficial e de fundo foram coletadas em quatro campanhas de amostragem em 2018. As variáveis ambientais foram medidas em campo usando uma multi-sonda: amônio (N-NH4+), condutividade elétrica (CE), nitrato (N-NO3-), pH, oxigênio dissolvido (OD) e temperatura da água (T); e no laboratório: nitrogênio total (NT) e fósforo total (PT). Foram realizados bioensaios com sementes de pepino (Cucumis sativus), agrião (Lepidium sativum) e mostarda (Sinapis alba) (n = 6). Os bioensaios consistiram em incubar as sementes e amostras de água em placas de Petri a (20º ± 2 ºC) na ausência de luz por 3 dias (S. alba) e 4 dias (C. sativus e L. sativum). Água ISO foi usada como controle positivo. Na sequência foram determinados o número de sementes germinadas e o comprimento das raízes para cálculo do Índice de Germinação (IG). Foram realizadas análises estatísticas, como o teste de Shapiro-Wilk, análise de variância (ANOVA) e teste de Tukey para verificar as diferenças entre as respostas das sementes às variáveis ambientais. A Análise de Componentes Principais (ACP) foi aplicada às variáveis ambientais e IG para identificar as variáveis mais representativas. O estudo indicou que em maio de 2018 a água subterrânea era moderadamente fitotóxica para L. sativum (IG = 61,3 ± 8,2%); e a água do fundo foi muito fitotóxica para L. sativum (IG = 23,6 ± 14,5%) e S. alba (26,2 ± 12,0%). Em todas as demais campanhas de amostragem, as amostras de água potencializaram a germinação das sementes, o que pode estar relacionado à concentração de nutrientes. A espécie L. sativum mostrou-se mais sensível, devido ao menor grau de dispersão dos dados e ao maior grau de toxicidade em relação às demais sementes analisadas.

Residence time of water flow is an important factor in subsurface media to determine the fate of environmental toxins and the metabolic rates in the ecotone between the surface stream and groundwater. Both numerical and lab-based experimentation can be used to estimate the residence time. However, due to high variability in material composition in subsurface media, a pragmatic model set up in the laboratory to trace particles is strenuous. Nevertheless, the selection and inclusion of input parameters, execution of the simulation, and generation of results as well as post-processing of the outcomes of a simulation take a considerable amount of time. To address these challenges, an automated particle tracing method is developed where the numerical model, i.e., flow and reactive transport code, MIN3P, and MATLAB code for tracing particles in saturated porous media, is used. A rectangular model domain is set up considering a fully saturated subsurface media under steady-state conditions in MIN3P. Streamlines and residence times of the particles are computed with a variety of seeding locations covering the whole model surface. Sensitivity analysis for residence time is performed over the varying spatial discretization and computational time steps. Moreover, a comparative study of the outcomes with Paraview is undertaken to validate the automated model (R2 = 0.997). The outcome of the automated process illustrates that the computed residence times are highly dependent on the accuracy of the integration method, the value of the computational time step, ∆t, spatial discretization, stopping criterion for the integration process of streamlines, location, and amount of seed points. The automated process can be highly beneficial in obtaining insights into subsurface flow dynamics with high variability in the model setup instead of laboratory-based experimentation in a computationally efficient manner.

Daerah Sambirejo, Kecamatan Prambanan, Kabupaten Sleman merupakan salah satu daerah sulit air berdasarkan kenampakan morfologi berupa perbukitan. Berdasarkan kejadian geologi disuatu daerah memiliki produk yang berbeda satu dengan yang lain. Produk geologi tersebut berupa morfologi, litologi dan genesis, sehingga berdampak pada pengaruh air tanah. Bertambahnya jumlah penduduk sangat berpengaruh pada kebutuhan air secara besar perhari. Daerah yang terindentifikasi kekurangan air, sehingga penting diketahui sebagai dasar untuk mengetahui daerah yang perlu dikaji lebih detail sebagai dasar eksploitasi air tanah dalam dan air bawah permukaan. Penelitian ini bertujuan untuk mengidentifikasi potensi air tanah di daerah Sambirejo. Masalah dalam penelitian ini adalah bagaimana menetukan daerah potensi air tanah yang berkwalitas dan bermafaat untuk memenuhi kebutuhan air baku pada masyarakat.Pemanfaatan air bawah permukaan sangat di perlukan untuk mendapatkan potensi yang besar dan dapat segera dimanfaatkan oleh masyarakat. Penelitian ini dilakukan dengan metode berupa pemetaan geologi untuk menentukan sebaran litologi dan pengukuran geofisika berupa pengukuran geolistrik untuk menentukan daerah potensi air tanah yang berada pada morfologi lereng dan pungungan. Berdasarkan dari hasil geolistrik keberadaan air tanah terdapat pada kedalaman 20-40 meter yang dikatagorikan dangkal sedangkan pada kedalaman 98-142 meter yang di katagorikan sebagai akuifer hampir dalam. Jenis akuifer yang berkembang pada daerah Sambirejo yaitu akuifer setengah tertekan (leaky unconfined aquifer) dimana batuan breksi pumice pada bagian bawahnya terdapat lapisan kedap air berupa tuff. Kata kunci: Aquifer, litologi, Air bersih, Sambirejo

Mercury is a global pollutant of critical concern but its movement through terrestrial upland systems is poorly understood. We investigated whether forest harvesting practices and varying hydrological conditions resulted in different subsurface transport pathways, fluxes and proportions of recent vs. ambient mercury in runoff. In a multiyear field experiment, we measured subsurface lateral mercury fluxes at three adjacent hillslope plots, including one that was not harvested, one where all biomass was removed after harvest, and one where residual biomass was left after harvest. Two different enriched stable mercury isotopes (Hg tracer) were added to the hillslope plots (one pre-harvest and one post-harvest) to help differentiate between recently deposited mercury and ambient mercury in soils, as well as to identify changes between years. More Hg tracer was recovered in runoff post-harvest (16.2–54.0 μg) than pre-harvest (3.7–11.8 μg) from both harvested hillslopes, but differences between harvested hillslopes were not significant. The movement of Hg tracer was governed by periods of near surface preferential flow that was enhanced by forest harvesting. Runoff Hg tracer concentrations were significantly and inversely related to both event runoff magnitude (R2 = 0.85) and runoff ratio (R2 = 0.81). Insignificant relationships between Hg tracer concentrations and both DOC and precipitation pH suggest that for recently deposited mercury, the overarching controls on mobilization were hydrological rather than biogeochemical. The dependence of mercury mobilization on the routing of precipitation to different subsurface flow pathways suggests an important interaction between climate and the age of mercury pools for mercury transport from terrestrial landscapes.

Iron oxide nanoparticles are utilised in a broad range of applications (magnetic data storage, biosensing, drug delivery, treatment and remediation of contaminated soil and groundwater); causing noticeable quantities of iron oxide nanoparticles to be released into the environment. In this study, aggregation and stability of iron oxide nanoparticles in water were investigated within the range of pH 3 – pH 9 at a constant concentration of iron oxide nanoparticles and humic acid. The pH of the solution was selected to be continuously monitored at pH 7 to investigate the transportation and deposition behaviour of iron oxide nanoparticles in porous media at different velocities. It was found that iron oxide nanoparticles were aggregated and settle down as settled particles at low pH (pH 3 – pH 5). Iron oxide nanoparticles were stable, mobile and transported at a high pH, which is the pH range of natural water (pH 6.5 – pH 8.5). Iron oxide nanoparticles were strongly attached to the silica sand at natural water velocity in porous media, which is 2.93 ml min-1. Overall, the presence of humic acid in aquifers and porous media, the pH range of natural water (pH 6.5 – pH 8.5) and the slow speed (2.93 ml min-1) of water are expected to be a key factor that enhances the stability and mobility of iron oxide nanoparticles in natural water and porous media.

Change of oceanic surface mixed layer depth (MLD) is critical for vertical exchanges between the surface and subsurface oceans and modulates surface temperature variabilities on various time scales. In situ observations have documented prominent intraseasonal variability (ISV) of MLD with 30–105-day periods in the equatorial Indian Ocean (EIO) where the Madden–Julian oscillation (MJO) initiates. Simulation of Hybrid Coordinate Ocean Model (HYCOM) reveals a regional maximum of intraseasonal MLD variability in the EIO (70°–95°E, 3°S–3°N) with a standard deviation of ~14 m. Sensitivity experiments of HYCOM demonstrate that, among all of the MJO-related forcing effects, the wind-driven downwelling and mixing are primary causes for intraseasonal MLD deepening and explain 83.7% of the total ISV. The ISV of MLD gives rise to high-frequency entrainments of subsurface water, leading to an enhancement of the annual entrainment rate by 34%. However, only a small fraction of these entrainment events (

Water management is a strategic factor in old coal mine working areas due to disturbance in the aquifer caused by subsidence resulting in drying of wells and streams. Cavity formation due to underground mining leads to roof fall, heaving of clay floors and collapse of coal pillars in soft clay floors. Logging of water in old mine workings is a common phenomenon especially during rainy season. Mine water is extensively used in various mining activities, and hence, a study has been conducted in part of Jamadoba 6 and 7 Pits, Jharia coalfield, India, to assess the hydrological condition during and post-monsoon. Initially, a conceptual model has been prepared to identify the possible sources of water including its path entering into old mine workings. Electrical resistivity tomography (ERT) i.e. Wenner-Schlumberger configuration with quality factor 5 has been adopted as it is effectual and reliable in detecting subsurface cavities at shallow depth and the possible path of transmission of subsurface water into the mine void with season variation. The study helped in identification of abandoned incline, porous and permeable strata conditions. The correlation of the resistivity variations is observed to be in close approximation with working plans and available borehole lithology. This technique proved to be suitable for adopting such studies.

Increased use of neonicotinoid-coated crop seeds introduces greater amounts of insecticides into the environment, where they are vulnerable to transport. To understand the transport of neonicotinoids from agricultural fields, we planted maize (Zea mays L.) seeds coated with thiamethoxam in lysimeter plots in central Pennsylvania. Over the next year, we sampled water generated by rainfall and snowmelt and analyzed these samples with mass spectrometry for the neonicotinoids thiamethoxam and clothianidin (metabolite), which originated from the coated seeds. For surface and subsurface transport, thiamethoxam exhibited "first-flush" dynamics, with concentrations highest during the first events following planting and generally decreasing for the remainder of the study. The metabolite clothianidin, however, persisted throughout the study. The mass of thiamethoxam and clothianidin exported during the study period accounted for 1.09% of the mass applied, with more than 90% of the mass transported in subsurface flow and less than 10% in surface runoff. These results suggest that surface runoff, at least for our site, is a relatively small contributor to the overall fate and transport of these insecticides and that the delivery ratio (i.e., mass exported/mass applied) observed for these compounds is similar to those of other trace-level emerging contaminants known to negatively influence aquatic ecosystems.

Due to water scarcity, storage and reuse of water has become a great challenge all over the world. The conventional methods for the wastewater treatment require large capital investment, operating cost, and need trained personal for supervision and maintenance. Therefore non conventional wastewater treatment methods have gained the popularity worldwide. Use of constructed wetland (CW) technology for wastewater treatment is highly efficient since CW are easy to construct, cost effective and increase the aesthetic value. Wetlands behavior and efficiency concerning wastewater treatment mainly depends upon macrophytes, substrate, hydrology, temperature and hydraulic retention time in the system. Present study deals with the removal of pollutants in two stage hybrid subsurface flow CW at different hydraulic retention times (HRT). The domestic wastewater was supplied to CW and treated using the available perennial macrophyte, Arundo donax. The system was run in replicate along with one control. To assess the removal efficiency of the pollutants, parameters like pH, temperature, dissolved oxygen (DO), total suspended solids (TSS), biological oxygen demand (BOD), chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN) were analyzed at different HRT i.e., 36, 30 and 24 h. The result of the study observed maximum percentage removal of TSS, BOD, COD, and TKN was up to 84.61, 98.37, 61.39 and 91.87% respectively at 30 h of retention time.

Process-based groundwater flow models are an important tool for gaining useful insights into the hydrogeological characteristics of a complex aquifer system. A conceptual model of a multilayer alluvial aquifer system at the base of Karewa mountain front is presented indicating the hydrogeological framework and the various flow processes affecting the groundwater flow system. Based on the conceptual model, a MODFLOW NWT-based numerical simulation model of groundwater flow was developed for the region. As interpreted from the hydrogeological framework, the simulation was carried out in the context of two aquifers, the top minor aquifer which is regarded as confined–unconfined and the lower major predominantly confined aquifer. Hydraulic heads measured in 104 wells during predevelopment period were used to calibrate hydraulic conductivity, natural recharge and evapotranspiration for the steady state model. For validation, observations from 38 wells corresponding to a recent steady state of aquifers were used. Performance statistic R2 = 0.83 and 0.79 for calibration and validation, respectively. Steady-state groundwater budgets including natural recharge were thus estimated. Calibrated horizontal hydraulic conductivity of aquifers is of the order of 0.0015–0.0031 m/s. Total natural recharge to the aquifers from precipitation and mountain subsurface flow corresponding to predevelopment and recent conditions was estimated as 96.39 and 64.21 Mm3/month, respectively. Steady-state simulations indicate an average decline of 2–5 m in groundwater heads over a period of about two decades, attributable to decreased recharge. Results of this model can help in sustainable development of groundwater in the region.

Evaluation a field-scale of constructed wetland (CW) for the treatment of rural wastewater (WW), in resource-scarce semi-arid tropic (SAT) villages, to provide improved wastewater management and increased water use efficiency, was the main objective of this study. A CW was commissioned in Kothapally village of Telangana to treat the wastewater generated from 100 households. The CW was vegetated with Typha latifolia and Canna indica. Average COD, sulfate and inorganic nitrogen removal efficiencies observed were 65%, 60% and 67% respectively, for the study period (one year). Removal efficiency for total coliform was consistently above 80%. The treated wastewater was stored in a farm pond and was utilized for irrigation in the nearby agricultural fields (0.6 ha). This perennial source of water, helped the nearby farmers to cultivate two additional crops, chickpea during rabi and sweetcorn during summer. The assured availability of water reduced their vulnerability to dry spells during the kharif by providing means for lifesaving irrigation. The biomass harvested from the constructed wetland was used as fodder for the livestock. A net additional income of Rs.70,000 (∼US$1,000) was realized by the farmers using the treated wastewater for cultivation. Similar constructed wetland-based wastewater management system can be scaled up across water scarce semi-arid tropics. Novelty statement Field-scale performance evaluation of constructed wetland based wastewater treatment in a semi-arid tropic village is scarce in the literature. The work presented gives a feasibility assessment for this technology critical for its wide-scale application to augment rural wastewater management in resource poor villages.

Agricultural and livestock farms are the major sources of freshwater pollution in rural areas in the Philippines. Small and unregulated dairy farms operate without appropriate wastewater treatment before discharge because it is too expensive to do so. With this scenario, the emergence of the need for a sustainable and cheaper alternative for wastewater treatment gave rise to the research and development studies of the efficiency of constructed wetlands. The study aims to analyze the treatment efficiency of series type vertical subsurface flow constructed wetlands planted with Napier Grass (Pennisetum Purpureum Schumach) on University of the Philippines Los Baños (UPLB) Dairy Farm wastewater with a focus on fecal coliform concentration, electric conductivity, total dissolved solids content, nitrite and nitrate concentration and pH level. The study showed that after treatment using the vertical subsurface flow constructed wetlands, all the parameters except the fecal coliform concentration were below the standard limits set by the Department of Agriculture with average removal efficiencies of 12.94% on Electric Conductivity (EC), 12.86% on Total Dissolved Solids (TDS), 216.44% on Nitrite (NO2-N), -125.64% on Nitrate (NO3-N), and -25.64% on Fecal Coliforms (FC). With the results of the analysis, a design of series type vertical subsurface flow constructed wetland for dairy farm wastewater treatment is suggested. Doi: 10.28991/cej-2021-03091654 Full Text: PDF

In this study, the effect of reed vegetation on evapotranspiration (ET) and treatment performance was estimated, and a commonly used meteorological estimate of potential evapotranspiration (PET) was compared with ET with vertical subsurface flow constructed wetlands (VSSFs) in the treatment of the high salinity of landfill leachates. The experimental approaches consisted of three runs: Run A was a poor reed vegetation bed, Run B was a dense reed vegetation bed, and Run C was a bed without reeds. The results of this study are as follows: The salinities of the leachate inflow in Run A and Run B were 15.8 ± 1.9g Cl-/L and 15.5 ± 2.8g Cl-/L, respectively. The average ETs of Run A, Run B and Run C were 4.2mm/d, 7.4mm/d and 3mm/d, respectively. The annual ET rates of Run A, Run B and Run C were 1535mm, 2702mm and 1101mm, respectively. On the other hand, those of PET estimated on the basis of the Hamon equation of 2017and 2018 were 741mm and 791mm, respectively. The PET rate was much less compared to the ET rate in the dense vegetation bed. It was necessary to consider site-specific factors such as growth of plants in the evaluation of the water budget. The water loss by evapotranspiration in Run B was much more than those in Run A and Run C. Although the removal rates calculated from the concentration between inflow and outflow did not differ between the dense vegetation bed and the poor vegetation bed, the load reduction rates calculated from the water budget differed between dense vegetation and poor vegetation.

Hydro-ecological models are important tools used to estimate streamflow from mountainous watersheds as driven by precipitation and snowmelt under the influence of different spatially variable hydro-ecological response variables. These models enable us to gain insight into hydrological and ecological processes occurring in the watershed. In the present study, a hydro-ecological model, Regional Hydro-Ecological Simulation System (RHESSys) was set up for a small representative watershed in Eastern Himalayan region of Arunachal Pradesh to investigate spatial variation in saturation deficit during snow depletion period. RHESSys model is capable of estimating variations in evaporation, transpiration, streamflow, overland flow, saturation deficit, etc. from the landscape. Studies related to hydrological and ecological sustainability of the Eastern Himalayan Rivers are limited, although a major part of the region is covered with evergreen forests, where ecological parameters may have a great impact on watershed hydrology. Nuranang watershed, which is located in Tawang district of Arunachal Pradesh, India, was selected as the study area. The hydro-meteorological data from 2004 to 2008 were collected from Central Water Commission (CWC). Digital Elevation Model (DEM) with 30 m spatial resolution was downloaded from NASA website. Calibration of the RHESSys model was performed for the depletion period of 2004 (13th April–21st August) and 2005 (17th April–4th September) and the model was validated for the years 2008 (17th April–20th September) and 2009 (13th April–23rd September) using observed streamflow at the watershed outlet. Comparison plot of the actual and log values of observed and simulated daily discharges showed that the model captured the variations in total observed discharge and subsurface flows reasonably well for both the calibration and validation years. Daily time-series outputs of various hydrological variables, i.e., subsurface flow, overland flow, streamflow, saturation deficit, and percentage saturated area, were obtained for both calibration and validation simulation. For simulation years, overland flow dominated stream discharge in all the months, and contributed around 60% of the total streamflow, whereas subsurface flow contributed around 40% in all the months. Comparatively, saturation deficit was more in the month of April due to less precipitation and it was reduced in the month of May because of pre-monsoon rainfall. It increased again in the month of June as the precipitation in the month was less compared to May. Then, it decreased again in the subsequent months of July and August due to high rainfall during the monsoon season and increased in the month of September. Average saturation deficit was estimated to be 389.69 mm and average percentage saturated area was estimated as 9.52%. The number of saturated pixels was found to be minimum in the month of April, while a maximum number of saturated pixels were observed in the month of August indicating the existence of inverse relationship between precipitation and saturation deficit for the study area.

The objective of this study was to evaluate the productivity of shoot dry biomass and the capacity of nitrogen (N), phosphorus (P) and potassium (K) extraction by the Vetiver and Tifton 85 grasses when cultivated in horizontal subsurface flow constructed wetlands (HSSF-CWs) whose porous medium was saturated with solutions containing different nutrient availability. The grass shoots were cut every 30 days to determine the productivity and N, P and K contents in the plant tissue. Models of productivity and the extraction capacity of each nutrient were obtained as a function of the nutrient concentration. Based on the results obtained, it was verified that the productivity of shoot dry biomass and the extractions of N, P and K by the Vetiver grass increased linearly with the nutrient availability of the nutritive solution. In relation to Tifton 85, quadratic models of productivity and N and K extraction were adjusted. The maximum productivity, N, P and K extraction by Vetiver grass were 513.4, 8.2, 1.9 and 10.39 g m

The purpose of this study was to analyze the effects of the application of multivariate criteria of principal components and hierarchical clustering as a mechanism for monitoring the performance of Tifton 85 grass (Cynodon spp.) planted in horizontal subsurface flow constructed wetland reactor (HSSF-CW) under different organic (OLR), nutritional and sodium loads of swine wastewater (SW). The HSSF-CW planted with Tifton 85 grass was used as a swine wastewater after treatment applying organic loading rates between 26.1 (1st cut) and 360.6 kg ha−1 day−1 COD (8th cut). The maximum performances of HSSF-CW consisted of 52.0 t ha−1 of productivity and 24.0% of crude protein, with the application of 59.7, 64.2, and 31.2 kg ha−1 day−1 of TKN, PT, and K+, respectively. The eleven original variables generated four new components, with PC4 accounting for 94.0% of total variance, a condition strengthened with four data groupings greater than 48% similarity and three data groupings greater than 95% similarity between the variables. There was a strong association between of nitrogen, phosphorus, and potassium concentration by the hierarchical grouping and the intermediate cuts and lower temperatures.

The goal of the work has been to assess the factors that led to the series of landslides, which ravaged the District of Kodagu situated in the mountainous Western Ghats, in 2018. The work has been accomplished through field investigations and analysis of field data. While commonly, studies in India lay emphasis on the geological aspects and anthropogenic factors associated with landslides, the present work intended to study in detail the hydrological aspects of the disaster, which wreaked havoc in the region characterised by deep soils, very heavy rainfall and a dense vegetation cover. All the slides of significant magnitude along a 25-km stretch of the Payaswini valley, draining the western slopes of the Madikeri hill range, were identified, and their land characteristics delineated using field surveys and maps. Soil characteristics of the region were determined through tests on samples collected from ten slide sites. Results from tests on texture, density and permeability were used to learn about the part played by subsurface water. Characteristics of rainfall during the year were investigated using field data from the worst affected region. Studies on progress of the Monsoon rain, an analysis of probability of extreme values and establishment of intensity–duration relationships were accomplished. A variable source area watershed model incorporating MODFLOW, the popular ground water flow simulation model, has been applied on a typical micro-catchment in order to study the growth of the saturated zone during rains. It has been inferred from the investigations that an unprecedented combination of extremely wet catchment and a very heavy spell of rainfall, rather than any commonly attributed factor, has been the primary cause of the disaster in the district. It is concluded that it would be a futile exercise working on this natural phenomenon devoid of extensive field studies, because of the uniqueness of the region.

Small and medium industries are experiencing growth every year. The home industry of tofu production is one of the small and medium industries that continues to grow and develop. However, there is a problem if the tofu production waste is disposed of directly into the waters, it will cause pollution due to the deposition of organic material. The research objective was to analyze the subsurface flow-wetlands with plants namely water hyacinth, apu wood and lemna minor to reducing TSS levels and stabilizing pH. This research an experimental with treatments including SSF-Wetlands without water plants (A1), SSF-Wetlands with water hyacinth (A2), SSF-Wetlands with apu wood (A3), SSF-Wetlands with lemna minor (A4) and SSF-Wetlands with water hyacinth, and apu wood (A5). The stages of this research are the sampling stage, the SSF-Wetlands manufacturing stage, the waste treatment stage and the pH and TSS testing stages. Data were analyzed using one-way ANOVA (SPSS 20). The results showed that the liquid waste of tofu in the initial sample was acidic, namely 3.94 and the TSS level was 858 mg / L. The pH condition of the waste after processing by the quality standard.  The highest increase in pH and decrease in TSS levels in the tofu liquid waste treatment was the SSF-Wetland processing with water hyacinth plants (A2). This shows that water hyacinth plants have a greater role in neutralizing pH and can absorb the most suspended matter compared to apu wood and lemna minor plants.

Geothermal springs are essentially un-affected by environmental conditions aboveground as they are continuously supplied with subsurface water with little variability in chemistry. Therefore, changes in their microbial community composition and function, especially over a long period, are expected to be limited but this assumption has not yet been rigorously tested. Toward closing this knowledge gap, we applied whole metagenome sequencing to 17 water samples collected between 2010 and 2016 from the Thermopyles sulfur-rich geothermal springs in central Greece. As revealed by 16S rRNA gene fragments recovered in the metagenomes, Epsilonproteobacteria-related operational taxonomic units (OTUs) dominated most samples and grouping of samples based on OTU abundances exhibited no apparent seasonal pattern. Similarities between samples regarding functional gene content were high, with all samples sharing >70% similarity in functional pathways. These community-wide patterns were further confirmed by analysis of metagenome-assembled genomes (MAGs), which showed that novel species and genera of the chemoautotrophic Campylobacterales order dominated the springs. These MAGs carried different pathways for thiosulfate or sulfide oxidation coupled to carbon fixation pathways. Overall, our study showed that even in the long term, functions of microbial communities in a moderately hot terrestrial spring remain stable, presumably driving the corresponding stability in community structure. This article is protected by copyright. All rights reserved.