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Seaver, G.A. and Kuzirian, A.M., 2024. Estuary nitrate sources and trends in Buzzards Bay. Journal of Coastal Research, 40(6), 1055–1067. Charlotte (North Carolina), ISSN 0749-0208. The determination of estuary nitrate sources originating through groundwater was the principal objective of this work. This required long timeline (35-year) measurements over many seasonal cycles. Typically, in this study, nitrate sources were an upgradient from estuaries at a significant distance, usually greater than 300 m (1000 ft), whereas groundwater flow that transported the nitrate near the coast in Buzzards Bay, Massachusetts, traveled only 0.45 m/d (1.5 ft/d). Thus, it takes years before a potential newly discovered nitrate source could be confirmed in the estuary. Investigation of estuary nitrate trends and the significance of obtaining winter nitrate measurements to investigations was more fully developed in this work. This showed that determining the estuarian nitrate trends also required a timeline much longer than the variability of the nitrate influx into the estuary. The large, summer-to-winter high nitrate (but not low nitrate) differences and the system's inherent physiological ecology were central to regulating nitrate in an estuary, despite greatly increased groundwater nitrate input. The winter measurement data explained this phenomenon. Finally, the data measurement program completed in Buzzards Bay proved to be ideal in answering these necessarily long timeline questions. The research suggested a new parameter be used to indicate an excess nitrate state of an estuary. These long-term data also allowed meaningful calculations of estuarine and groundwater nitrate and temperature trends. [ABSTRACT FROM AUTHOR]

This study aims to investigate the response mechanisms of groundwater microbial‐toxicological indicators, specifically total bacteria count (TBC) and total coliform count (TCC), to water quality indicators and environmental conditions. Using data from a water source in the western plateau of China, a predictive model focusing on TBC and TCC was developed. An orthogonal experimental design was employed to manipulate environmental conditions such as temperature, pH, and porosity, facilitating laboratory experiments. These experiments measured pH, chemical oxygen demand (COD), oxidation–reduction potential (ORP), TBC, and TCC at varying depths and environmental conditions. Principal component analysis elucidated the mechanisms by which water quality indicators and environmental conditions affect groundwater microbial–toxicological indicators. A prediction model for these indicators in plateau regions was established based on a backpropagation neural network (BP‐NN), using TBC and TCC as target variables and the newly extracted principal components as influencing factors. The results demonstrate that environmental conditions and water quality indicators primarily influence the evolution of groundwater microbial–toxicological indicators by altering the ionic charge quantities, redox conditions, and temperature of the groundwater. The predictive model for groundwater microbial–toxicological indicators shows trends consistent with experimental outcomes, with an average relative error of less than 15%, meeting engineering requirements. Practitioner points: The values of total bacteria count (TBC) and total coliform count (TCC) under different conditions were obtained by column experiments.The influence mechanism of environmental conditions and groundwater indicators on TBC and TCC was elaborated by principal component analysis.TBC and TCC prediction models were established through the investigation of water sources in a plateau area and laboratory experiments. [ABSTRACT FROM AUTHOR]

Intertidal groundwater springs provide thermally stable, nutrient‐rich freshwater that causes fine‐scale variability in water temperature and salinity and promotes biodiversity in coastal estuaries and lagoons. In this study, we combined three thermal sensing techniques to elucidate summer water temperature patterns at the mouths of intertidal groundwater springs and the ambient coastal lagoon in Prince Edward Island, Canada. Thermal infrared imagery captured the spatiotemporal variability in relative temperatures of the lagoon channel and cold‐water plumes from the springs. Thermal anomalies due to the springs were detected at the surface throughout a tidal cycle, suggesting that the thermal plumes were buoyant. Fiber‐optic distributed temperature sensing paired with temperature loggers near the spring outlets recorded groundwater temperatures at low tide (~ 7°C) but ambient lagoon temperatures (up to 26°C) at high tide due to the vertical thermal gradient in the stratified water column. Calculated estuarine Richardson numbers throughout the study confirm intertidal spring buoyancy due to salinity differences. The fiber‐optic distributed temperature sensing results revealed pronounced variations in temperature as evidenced by spatial (3.7°C) and temporal (5.5°C) standard deviations over the cable length during the study and lower mean lagoon bed water temperatures at high tide (22.5°C) than low tide (24.3°C) due to heat advection from tidal pumping. Lagoon temperatures fluctuate at diurnal (solar) and semi‐diurnal (tidal) frequencies. The findings emphasize the efficacy of a multi‐technology approach to reveal fine‐scale and dynamic thermal processes that drive temperature patterns and habitat distribution in coastal lagoon ecosystems and highlight the thermal influence of intertidal springs. [ABSTRACT FROM AUTHOR]

This investigation aims to study the influence of various environments, such as groundwater, seawater, mineral water and sub‐zero, on reinforced polyester/S‐glass/sisal composites with nano clay (NC). Composites with a configuration of S‐glass/sisal/sisal/S‐glass (GSSG) with different wt% of NC, such as 0, 2, 4, and 6, were manufactured using the hand lay‐up method. For 6 days, the composites were conditioned in different environments like seawater, mineral water, groundwater at room temperature, and sub‐zero environments at −17°C. The influence of these environments on the tensile and flexural properties of manufactured composites was studied. Composites with 4% NC displayed higher tensile strength, while composites with 2% NC exhibited maximum flexural strength for all the environments. It was perceived that the weight gain was maximum in seawater (0.1857 g) and minimum in mineral water (0.06 g) and sub‐zero (0.101 g) conditions for 6% NC condition. Tensile and flexural strengths were reduced by 27% and 24% when samples were submerged in seawater compared to other environments. TEM images for 4 wt% of NC and 6 wt% of NC were studied for dispersions of NC in Polyester, and the effect of NC mixing with polyester was understood for the hybrid polymer composites. Highlights: A novel hybrid composites were fabricated using a double stirring process.The ultra‐sonication led to uniform distribution of nanoparticles.The mechanical properties and the effect of environments on these properties are studied.SEM images revealed the aging due to various environments.The hybrid composites can store mineral water and the sub‐zero environment. [ABSTRACT FROM AUTHOR]

Rajgir thermal spring field in Bihar, Eastern India, holds international significance due to its historical and multi-religio-cultural importance. Present study attempted to understand the aquifer system to arrest its diminishing discharge in the backdrop of climate change and urbanization. The study identified three aquifer systems, namely fractured quartzite, basement granite, and overlying alluvium, that are working in tandem toward the delicate balance in recharge and discharge in the thermal spring field controlled by the regional fault system. Geological study along with geophysical surveys through gradient resistivity profiling, vertical electrical sounding, and electrical resistivity tomography is carried out to identify local distribution of the fault system. Based on the study, a geological map of the area is prepared followed by preparation of water table contour map. Study of exploratory borehole tapping the fracture zone reveals that the fracture system is under thermo-artesian condition capable of 5 m3/h yield with 40 m drawdown. This translates into transmissivity of about 1 m2/day. Historical rainfall, spring discharge, and groundwater hydrograph of the area are correlated and show that an average time lag of about 20–30 days exists between peak rainfall and peak groundwater level and about 30 days between peak rainfall and peak discharge. It highlights the importance of local recharge for survival of the thermal spring field. Rainfall and potential evapotranspiration data analysis shows that recharge occurs only when annual rainfall exceeds 850 mm, making the variability in rainfall due to climate change a potential threat to adequate recharge. The area is also witnessing growing urbanization which is altering the local groundwater regime. Analysis of historical water level shows that groundwater table declined by about 2 m in the last decade. Comparison with earlier studies is used to identify the changes in groundwater flow pattern in the area. Spatial variation in groundwater temperature is mapped and statistically analyzed. Results show that temperature above 30.8 °C may be considered as samples having signature of thermal water component. It is also observed that thermal water is restricted in some fixed pathways. Discharge measurements are carried out to study diurnal variation and effect of pumping. A set of private borewells, where thermal water is reported, is also studied. Typically, these wells are limited to the weathered part of the rock formation and do not tap fractures. Based on hydrogeological scenario, a local hydrodynamic model is conceived. Further, a management plan is suggested for sustenance of the thermal spring field with potential solution involving establishment of a carefully regulated zone with prohibition of energized pumping. Based on the present study, Government of Bihar has accepted the recommendation and is in the process of implementation. [ABSTRACT FROM AUTHOR]

The main objective of this research was to develop a geological and geophysical modeling to infer the geometry and thickness in the sedimentary sequence of the middle basin of the Bogotá River with emphasis on the Guadalupe Group, reconstructing the stratigraphic sequence, structural setting, hydrogeological modeling, and potential geothermal uses. Various geophysical methods were applied, including vertical electrical soundings (VES), and magneto telluric soundings (MT-VES), whose results were complemented with the interpretation of seismic lines, regional and local gravity anomaly maps, and borehole data, among others, which allowed to model the subsurface from the surface to depths beyond 3000 meters, with emphasis on the interval between 500m to 1000m depth. Integrated models were developed from interpretations of electrical resistivity data, gravity and magnetic data, reflection seismic and borehole data. Based on the results, potential deep aquifers have been proposed to be confirmed by drilling. These deep aquifers can contribute to satisfy the need for water, which historically has been explored and overexploited from shallower aquifers in this sector of the basin. A recommendation was also made to consider the potential of low enthalpy thermal energy for agro-industrial purposes associated with groundwater's temperature at the depth of this research. As a result, the modeled sedimentary sequence is characterized by a thick quaternary overburden overlying an intensively folded and faulted Neogene, Paleogene, and upper Cretaceous formations, mainly composed of siltstone, sandstones, and shale sequences of fluvial and marine environment, including facies of marine regressions and transgressions near the coastline. The penetration obtained allows establishing a high hydrogeological potential in the first 2000m depth, especially associated with the Guadalupe group, where the Labor and Tierna and Arenisca Dura formations have the highest hydrogeological potential. In addition, the preliminary estimation of thermal gradients suggest that low enthalpy geothermal energy potential is feasible to be used for the agro-industrial demand of energy of the study area. [ABSTRACT FROM AUTHOR]

Hydrothermal geothermal energy, as a widely distributed, large reserve and easily exploitable renewable source, can be used for both power generation and building heating. In this study, a numerical simulation of heat extraction performance is conducted based on monitoring well temperature data in a geothermal field in Xiong'an New Area. The effects of the reinjection temperature, injection flow rate, and reinjection rate on the outlet temperature and the reservoir temperature during a long-term operation are analyzed. The results indicate that the lower reinjection temperature can generate a critical disturbance scope for the thermal reservoir during the exploitation process. The impact scope on the thermal reservoir can reach 210.3 m at a reinjection temperature of 25 °C, which is not conducive to maintaining the outlet temperature of production wells in the long-term. The reinjection rate significantly affects both the horizontal and vertical temperature fields of the thermal reservoir. Under reinjection conditions of 30 °C and 40 kg/s, the horizontal and vertical impact scope of the thermal reservoir are 262.3 and 588.5 m, respectively. The reinjection rate is inversely related to the outlet temperature. A decrease from 100% to 70% in the reinjection rate can increase the outlet temperature by 4.21%. However, a decrease in the reinjection rate will lead to a decline in the groundwater level. Therefore, balancing the variation in outlet temperature and groundwater level is crucial in practical engineering. [ABSTRACT FROM AUTHOR]

Alluvial aquifers often exhibit highly conductive embedded formations that can act as preferential pathways for the transport of solutes. In this context, a detailed subsurface characterization becomes crucial for an effective monitoring of groundwater quality and early detection of contaminants. However, small-scale heterogeneities are seldom detected by traditional nondestructive investigations. Heat propagation in porous media can be a relatively inexpensive tracer for groundwater flow, potentially offering valuable information in various applications. In this study, we applied passive Fiber Optics Distributed Temperature Sensing (FO-DTS) to a group of observation wells in a highly heterogeneous phreatic aquifer to uncover structures with different hydraulic conductivity, relying on their response to temperature fluctuations triggered by natural and anthropogenic forcings. A comprehensive data analysis approach, combining statistical methods and physics-based numerical modeling, allowed for a three-dimensional characterization of the subsurface at the experimental site with unprecedentedly high resolution. [ABSTRACT FROM AUTHOR]

Dendritic stream networks are an intriguing subject for exploring the spatial and temporal variability of the rare and common bacterial biosphere, yet very few such studies have been conducted. We sampled riverine bacterioplankton at 13 sites in a subarctic riverine network across 3 years, with five sampling times each year. Ordinations showed a consistent pattern of downstream shift for both rare and abundant subcommunities. We also detected a temporal signal, with seasonal community shifts reflecting changes in water temperature and groundwater contribution, and an inter‐annual pattern where the year 2018 differed from other years. Phylogenetic turnover of the rare subcommunity indicated homogeneous selection, whereas the abundant subcommunity was mainly stochastically structured. Transiently rare taxa were the dominant type of rarity with the highest proportion at the headwater regions. The bacterioplankton community was characterized by a small group of core taxa that occurred at most sites with little temporal variation, a very large number of permanently or transiently rare taxa, and taxa shifting through time between the rare and abundant biosphere. While this basic structure could have been detected with less extensive temporal replication, a comprehensive understanding of the rare biosphere in riverine bacterioplankton can only be achieved via inter‐annual, spatially replicated sampling that covers the whole stream network. [ABSTRACT FROM AUTHOR]

The groundwater characteristics of the Učja aquifer were investigated using geochemical and isotopic data. The water discharge and physico-chemical properties of the groundwater and the Učja River ref lect the climate that is characteristic of the area. The mixed snow/rainfall regime is characteristic for the Učja Valley, with the highest discharges appearing during the spring snowmelt and autumn precipitation, and the lowest discharges in the winter and especially summer months. The temperature of the groundwater and the Učja River is lower in winter and higher in summer. The specific electrical conductivity values indicate a very permeable carbonate aquifer. Higher conductivity values were observed in spring and autumn at all sampling sites, which is related to snowy and rainy periods. The groundwater from the Učja aquifer indicates a uniform type of water (Ca-Mg-HCO3), with Ca2+, Mg2+ and HCO3 - the most abundant ions. Differences in Ca2+ and Mg2+ concentrations and in the Mg2+/Ca2+ molar ratio between sampling sites were observed. Those springs with lower Mg2+ and lower Mg2+/Ca2+ molar ratios indicate limestone recharge areas, and those springs with higher Mg2+ and molar ratios indicate interaction with the dolomite hinterland. The pH values confirm alkaline waters characteristic of carbonate aquifers. The hydrogen (δ²H) and oxygen (δ18O) isotope values suggest the main source of water is from precipitation from a complex mixing of maritime and continental air masses. An altitude isotopic effect is observed with minor δ18O and δ²H depletion at higher altitude sampling sites compared to those springs at lower altitudes. The altitude isotopic effect is most prominent in spring. The δ13CDIC values indicate the dissolution of carbonates and the degradation of organic matter. [ABSTRACT FROM AUTHOR]

Rural communities in Mexico and other countries with limited economic resources require a low-cost measurement system for the piezometric level and temperature of groundwater for their sustainable management, since anthropogenic action (pumping extractions), natural recharge and climate change phenomena affect the behavior of piezometric levels in the aquifer and its sustainability is at risk. Decrease in the piezometric level under a balanced level promotes salt intrusion from ocean water to the aquifer, salinizing and deteriorating the water quality for agriculture and other activities; and a decrease in water level under the pumps or well drilling depth could deprive communities of water. Water temperature monitoring is essential to determine electric conductivity and dissolved salt content in groundwater. Using IoT technology, a device was developed that monitors both variables inside the well, and the ambient temperature and atmospheric pressure outside the well. The measurements are made in real time, with sampling every second and sending data to a dedicated server every 15 min so that the visualization can be accessed through a device with Internet access. The time series of the variables measured inside and outside the well were obtained over a period of three months in the rural community of Agua Blanca, Guasave, Sinaloa, Mexico. Through these records, a progressive temporary drawdown of the piezometric level is observed, as well as the frequency of pumping. This low-cost IoT system shows potential use in hydrological processes of interest such as the separation of regional and local flow, drawdown rates and recognition of geohydrological parameters. [ABSTRACT FROM AUTHOR]

The Gulf of Maine hosts the southernmost remaining population of North American Atlantic salmon. Despite extensive hatchery supplementation since the late 1800s, and more recent riverine habitat restoration efforts and fishing restrictions, US-origin Atlantic salmon populations continue to decline and have remained at low abundance over recent decades. Climate change has been identified as a critical threat to the future of US Atlantic salmon. In this study, we synthesized available information on how habitats used by Atlantic salmon across all their life stages will be affected by climate change as well as the suitability of future conditions for salmon's persistence in the region. Maintaining sufficient cool water refugia during increasing summer temperatures in riverine habitats is required for sustaining salmon in the future. Changes in groundwater quantity and temperature, which will depend on future precipitation and temperature, will be critical factors for river temperatures, as will land use and land cover. While Atlantic salmon's freshwater life stages are heavily documented, the marine phase is relatively less studied. Climate models predict basin-scale changes over the next century, but impacts to salmon are difficult to predict. Furthermore, disparate drivers and differential rates of change between freshwater and marine habitats could present an obstacle to the transition between phases in the future. We have a general understanding of migration patterns and prey preferences but lack a clear picture of how salmon respond to habitat and ecosystem-level changes associated with climate change progression. More research to understand freshwater habitat changes and salmon's marine spatiotemporal distribution responses will enhance capacities to evaluate future risks and predict impacts of climate change to US-origin Atlantic salmon. [ABSTRACT FROM AUTHOR]

Groundwater temperature is one of the main factors that is considered when deciding on installation of a vapor compression refrigeration system with groundwater used for heat transfer. Groundwater temperature measurement is a necessity for the system installation. A total of 75 groundwater wells within the Chiang Mai Basin were selected for temperature monitoring stations. The temperature-depth profile of shallow groundwater showed that temperature had little change below 2 m depth from the water table. The temperature-depth profile of deep groundwater showed the separation of upper and lower temperature zones. Mostly, the temperature of the upper zone of deep groundwater has a positive slope. The temperature of the lower zone of deep groundwater is relatively constant. Both the shallow and deep groundwater temperatures are below the atmospheric temperature. The seasons, hydrogeologic units, and land use types have affected groundwater temperature of the Chiang Mai Basin only little. [ABSTRACT FROM AUTHOR]

The thermal influence of urban infrastructure on groundwater resources is a growing concern in hydrogeological studies, particularly in the context of urban heat islands. This research presents a novel approach to quantifying this influence using building density as a proxy for estimating groundwater temperatures (GWT) in urban areas. Using a GISbased methodology, we constructed circular buffers with a radius of 600 meters centred on groundwater monitoring wells to calculate urban density. Our model demonstrated a strong correlation between building density and GWT, with a correlation coefficient (R 2 ) of 0.94, indicating a substantial thermal impact of urban structures within this range. The precision of our model was highlighted by the average deviation of 0.34 °C between predicted and measured groundwater temperatures, and a maximum error of 0.79 °C. A case study in Bratislava city validated the model’s effectiveness, showing an almost perfect correlation between urban density and GWT. The findings suggest that our approach provides a reliable and simplified method for predicting GWT in urban environments. However, to generalize our model, further research is recommended that incorporates data from various cities and considers additional variables such as groundwater flow. This study contributes to the field of urban hydrogeology by offering a methodological advancement for the assessment and management of groundwater resources in densely built environments. [ABSTRACT FROM AUTHOR]

Since decarbonization of the energy sector is among the top priorities in the EU, with ambitious targets of carbon neutrality until 2050, the energy efficiency of the building stock and the use of renewables are those directions, which can bring the most considerable input towards the achievement of these goals. However, it is not always obvious how to efficiently combine different aspects of low energy demand, availability of renewables, part load operation conditions etc. The results of dynamic IDA ICE simulations highlight that the introduction of renewable low-carbon energy sources should be thoroughly coupled with building energy systems and only their full compatibility can give a high efficiency of the entire energy supply system of the building. Analysing simulation data, it was concluded that for low-energy buildings, heat pumps would not always show higher COP values, compared to buildings with higher energy demand. Ground source heat pump (GSHP) will not always be more efficient than air source heat pump (ASHP). If the ground/groundwater temperature is lower than 10 °C, for GSHP it will be almost impossible to over-compete ASHP within the same system. While COP with radiators and underfloor heating differs only by 10 %, both for ASHP and GSHP. [ABSTRACT FROM AUTHOR]

Changes in climate and land use will alter groundwater heat transport dynamics in the future. These changes will in turn affect watershed processes (e.g., nutrient cycling) as well as watershed characteristics (e.g., distribution and persistence of cold‐water habitat). Thus, groundwater flow and heat transport models at watershed scales that can characterize and quantify thermal impacts of surface temperature change on groundwater system temperatures may support forecasting changes to groundwater‐linked ecosystems in riparian zones, streams, and lakes. Including unsaturated zone processes has previously been shown to be important for properly determining the timing and magnitude of groundwater recharge (Hunt et al. 2008). Similarly, heat transport dynamics in the saturated‐zone, as well as connected surface‐water systems, can be appreciably influenced by unsaturated‐zone processes; in this way the unsaturated zone forms an inextricable link between the land surface where change occurs and the groundwater system that transmits that change. This paper presents new capabilities for the existing MT3D‐USGS transport simulator by adding functionality for simulating heat transport through the unsaturated zone. New simulation capabilities are verified through comparison of simulation results with those of the variably saturated heat transport simulator VS2DH under steady and transient conditions for both water and heat flow. The new capabilities are assessed using a number of conceptualizations and include evaluations of convective and conductive heat flow. These additional capabilities increase the utility for applied watershed‐scale simulations, which in turn may facilitate more realistic characterizations of temperature change on thermally sensitive ecosystems, such as stream habitat. Article impact statement: We document new capabilities in MT3D‐USGS for simulating heat transport in the unsaturated‐zone and verify code modifications with VS2DH. [ABSTRACT FROM AUTHOR]

Low-enthalpy geothermal energy (LEGE) is a carbon-free and renewable source to provide cooling and heating to infrastructures (e.g. buildings) by exchanging their temperature with that of the ground. The exchange of temperature modifies the groundwater temperature around LEGE installations, which may contribute to enhancing the capacity of aquifers to degrade organic contaminants of emerging concern (OCECs), whose presence is significantly increasing in urban aquifers. Here, we investigate the impact of LEGE on OCECs and their bioremediation potential through numerical modelling of synthetic and real-based cases. Simulation results demonstrate that: (i) LEGE facilities have the potential to noticeably modify the concentrations of OCECs; and (ii) the final impact depends on the design of the facility. This study suggests that optimized LEGE facility designs could contribute to the degradation of OCECs present in urban aquifers, thus improving groundwater quality and increasing its availability in urban areas. [ABSTRACT FROM AUTHOR]

Rationale: Noble gases are widely used as physically based climate proxies, notably in dissolved water samples as tracers of past recharge temperature in groundwater and air–sea gas exchange processes in seawater. Recent advances in measuring large‐volume samples of dissolved noble gas isotopic ratios at high precision have expanded the range of climate parameters that can be interpreted. Methods: We build on prior methods for measuring noble gas stable isotopes at high precision with a new large‐volume equilibration (LVE) method wherein sample gases are equilibrated in the sample flask between the dissolved phase and the headspace. The original dissolved gas composition is determined by measuring the headspace gases and correcting for the equilibrium dissolved gas content of the discarded water using known solubilities and fractionation factors. We evaluate the accuracy and precision of this method with air‐equilibrated water standards of known noble gas composition. Results: Replicate air‐equilibrated water standards and field measurements demonstrate that the LVE method achieves comparable precision to prior methods, with major advantages of measuring the Ne content as a constraint on excess air and allowing for long‐term sample storage. Isotope ratios measured with the LVE method in replicate samples were consistent between two laboratories, and LVE elemental noble gas abundances agreed closely with replicate samples measured using established copper‐tube methods and static noble gas mass spectrometry. Conclusions: The new LVE method enables reconstruction of past water table depths at ±1 m precision along with excess air, recharge temperature, and age and hydrogeochemical indicators. It has wide application to investigating climate signals and physical gas exchange processes in groundwater and seawater. [ABSTRACT FROM AUTHOR]

In order to analyze the rationality of the compound well structure and the degree of heat penetration of groundwater in a groundwater ground source heat pump project in a certain district of a city, the author proposed a method for building energy consumption simulation and groundwater flow numerical model. The variation trend of groundwater temperature under different heat transfer temperature difference is simulated and predicted. The experimental results show that the fitting points where the error between the simulated predicted temperature and the actual measured temperature does not exceed 0.5 1 account for 51.7%, the fitting points where the error is 0.5~1 account for 28.7%, the fitting points where the error is 1~2 account for 18.1%, and the fitting points where the error is greater than 2 account for 1.5%. The dynamic change trend of the simulated predicted temperature curve is basically consistent with that of the actual measured temperature curve. It is proved that the building energy consumption simulation and the numerical model of groundwater flow can effectively analyze the rationality of the compound well structure of the groundwater ground source heat pump project and the degree of groundwater heat penetration. [ABSTRACT FROM AUTHOR]

A hydro-geochemical characterization was conducted in the northern part of the Sonora River basin, covering an area of 9400 km2. Equipotential lines indicated that groundwater circulation coincided with the surface water flow direction. Based on the groundwater temperature measured (on average ∼21 °C), only one spring exhibited thermalism (51 °C). Electrical conductivity (160–1750 μS/cm), chloride and nitrate concentrations (>10 and >45 mg/L) imply highly ionized water and anthropogenic pollution. In the river network, δ18O values revealed a clear modern meteoric origin. Focused recharge occurred mainly from the riverbeds during the rainy season. During the dry season, diffuse recharge was characterized by complex return flows from irrigation, urban, agricultural, mining, and livestock. Drilled wells (>50 m) exhibited a strong meteoric origin from higher elevations during the rainy season with minimal hydrochemical anomalies. Our results contribute to the knowledge of mountain-front and mountain-block recharge processes in a semi-arid and human-altered landscape in northern Mexico, historically characterized by limited hydrogeological data. [ABSTRACT FROM AUTHOR]

In the last few years, several articles have studied heat as a groundwater tracer and developed analytical geothermal solutions to predict the subsurface temperature and groundwater fluxes. These solutions can be sorted into steady‐state and transient solutions. The steady‐state solutions cannot describe the time‐varying subsurface temperature, while the transient solutions ignore subsurface thermal boundary effects. Moreover, soil type may be another crucial factor significantly affecting the prediction results. This study compares six existing classical analytical solutions to examine the effects of soil types and subsurface thermal boundaries on simulating temperature‐depth profiles and estimating groundwater fluxes. Several synthetic cases are built by considering the common soil types, sand and clay, to demonstrate their effects on predicting the profiles. A field case is used to show the effect of subsurface thermal boundaries on the groundwater flux estimated by an inverse approach. The study results indicate that the soil types have significant influences on simulating the profiles, and the influences grow with time. Some existing solutions may give inaccurate estimations of the field groundwater flux since they merely consider the heat source from the temperature variations on the ground surface but ignore possible thermal boundary effects in the subsurface. These findings will be valuable to those applying heat as a tracer to investigate infiltration. [ABSTRACT FROM AUTHOR]

Hydrogeologists and mechanical engineers approach the design of geoexchange systems, and the associated borehole heat exchanger (BHE) fields, in different ways, each focusing on their knowledge areas. While these differences have created a strong research base, with well‐published innovations and designs that collectively allow for sustainable systems, industry has not embraced these recent advancements. Despite abundant research demonstrating how complex shallow groundwater flow and temperature conditions can influence BHE design and operation, the low‐temperature geothermal industry remains largely fixed on simple analytical codes and assumed uniform ground conditions. Geoexchange system inefficiencies become masked via reduced heat pump performance and increased electricity consumption. Similarly, interactions between BHE fields and infrastructure in urban areas are slow to manifest and are often unrealized due to a lack of field temperature data. While regulations that include hydrogeological factors have been developed in some jurisdictions, they are largely voluntary or rudimentary and can be unapplied in industry. Addressing this application gap may be unreasonable as designing and installing thermally efficient geoexchange systems can put them out of the cost envelope of competing heating and cooling systems. Perhaps for hydrogeologists, the way forward lies in the use of BHE's to facilitate contaminated sites remediation, an area we are familiar with, and one that allows for innovative technologies to reduce cost envelopes. Following that path, hydrogeologists can help improve system efficiencies while fully considering the dynamic nature of advective and thermal transport by groundwater. Article Impact Statement: Poorly performing, groundwater dynamic, geoexchange systems are the result of industry difficultly applying well‐published innovations. [ABSTRACT FROM AUTHOR]

Low-enthalpy geothermal energy (LEGE) is a carbon-free and renewable source to provide cooling and heating to infrastructures (e.g. buildings) by exchanging their temperature with that of the ground. The exchange of temperature modifies the groundwater temperature around LEGE installations, which may contribute to enhancing the capacity of aquifers to degrade organic contaminants of emerging concern (OCECs), whose presence is significantly increasing in urban aquifers. Here, we investigate the impact of LEGE on OCECs and their bioremediation potential through numerical modelling of synthetic and real-based cases. Simulation results demonstrate that: (i) LEGE facilities have the potential to noticeably modify the concentrations of OCECs; and (ii) the final impact depends on the design of the facility. This study suggests that optimized LEGE facility designs could contribute to the degradation of OCECs present in urban aquifers, thus improving groundwater quality and increasing its availability in urban areas. [ABSTRACT FROM AUTHOR]

The accurate assessment of groundwater levels is critical to water resource management. With global warming and climate change, its significance has become increasingly evident, particularly in arid and semi-arid areas. This study compares new extreme learning machines (ELM) methods tuned with metaheuristic algorithms such as particle swarm optimization, grey wolf optimization, the whale optimization algorithm (WOA), Harris Hawks optimizer (HHO), and the jellyfish search optimizer (JFO) in groundwater level estimation. Daily precipitation and temperature datasets acquired from two stations in northern Bangladesh were used as inputs to the models, which were evaluated based on different quantitative statistics and assessed based on RMSE, MAE, R2, and some new graphical inspection methods. The outcomes of the applications revealed that the efficiency of ELM models was considerably improved by using metaheuristic algorithms. The ELM-JSO improved the RMSE of the standalone ELM model by 13% for the optimal precipitation, temperature, and groundwater level inputs in the testing stage. Among the implemented methods, the ELM-JFO performed the best in estimating the daily groundwater level, and the ELM-WOA and ELM-HHO, respectively, followed it. Viability of a new extreme machine learning (ELM) method tuned with Jellyfish search optimizer (JFO) is investigated in groundwater level estimation. The ELM-JFO is compared with hybrid ELM-PSO, ELM-WOA and ELM-HHO models using daily precipitation and temperature data acquired from two stations of Bangladesh. The ELM-JSO improves the root mean square error of the standalone ELM model by 13% for the optimal precipitation, temperature and groundwater level inputs. [ABSTRACT FROM AUTHOR]

Rising temperatures and diminishing groundwater availability due to the current climate crisis are predicted to expose cave faunas in eastern North America to unprecedented environmental conditions that could prove detrimental to their unique ecosystems. Organisms that inhabit relatively stable environments like caves are known to develop narrow physiological tolerances. Cave habitats with their organisms are simple ecosystems whose homogeneity offers an ideal system for testing the ability of a highly specialized fauna to tolerate abiotic changes. We tested the capability of a cave-specialized beetle in the eastern United States, Darlingtonea kentuckensis Valentine, to withstand future climatic shifts in its environment. We exposed individuals to a range of relative humidities and temperatures for 10 days. The data strongly suggest that there is a temperature threshold for the survival of D. kentuckensis, but it is a higher thermal tolerance than would be expected in an environment that has not fluctuated in recent evolutionary time and suggests remnant physiological characteristics of ancestral epigean carabids. Decreasing the relative humidity in the environment resulted in a much more dramatic decline in survival, indicating highly evolved specialization for constant high-humidity environments. The narrow humidity threshold in which troglobionts can survive may be a much more apparent limiting factor than temperature in adapting to climatic shifts within a cave environment. [ABSTRACT FROM AUTHOR]

• Intermittent freshwater extraction and cold-water recharge can reduce the total salt mass. • Intermittent and continuous methods achieve comparable effectiveness in mitigating SWI. • Total salt mass exhibits a delayed and prolonged response to heat storage reduction. • A far recharge distance and low permeability delay thermal impacts of cold-water recharge. Decreasing groundwater temperature by freshwater extraction and cold-water recharge can mitigate seawater intrusion in coastal aquifers. However, the impact of frequently employed and easily executed intermittent well operations on this has been overlooked. This study numerically examines temperature and salinity distributions in coastal aquifers subject to intermittent freshwater extraction and cold-water recharge (IER) at an equal rate. Results show that IER maintains an equivalent effect on inhibiting seawater intrusion as the continuous method, while IER during cold seasons reduces operational time and cooling heat consumption. For instance, numerical test on a realistic aquifer shows that 90 d of IER could lead to a 75% decrease in operational time and a 29% reduction in cooling energy usage compared to the continuous method. The mitigation effectiveness depends on the averaged seaward hydraulic gradient, which is affected by heat storage reduction above the saltwater wedge. The cold-water plume from IER is convergently transported and discharged, creating a pronounced fluctuation of heat storage reduction and thereby resulting in a delayed periodic variation of the hydraulic gradient. As salt efflux is an integrated result of periodically changing hydraulic gradients, total salt mass exhibits a delayed and prolonged response to the variation of heat storage reduction. Sensitivity analyses show that a far recharge distance and reduced aquifer permeability increase the delay between heat storage reduction and total salt mass, and low recharge temperature facilitates seawater intrusion mitigation. This study demonstrates the importance of the intermittent method in inhibiting seawater intrusion and has implications for sustainable management of coastal groundwater resources. [ABSTRACT FROM AUTHOR]

Microbial reductive dechlorination is a key process in aquifers contaminated with chlorinated ethenes and results in a net mass reduction of organic pollutants. Biodegradation rates in the subsurface are temperature-dependent and may be enhanced by increased groundwater temperatures. This study explores the potential of combining the temperature increase from low-temperature Aquifer Thermal Energy Storage with In Situ Bioremediation (ATES-ISB). The effects of highly dynamic groundwater flow and heat transport on microbial degradation rates were examined in a contaminated aquifer based on a pilot-scale experiment and a comprehensive process-based modeling analysis. The low-temperature ATES-ISB pilot test was carried out in Birkerød (Denmark), in an aquifer contaminated with trichloroethene by implementing a groundwater flow dipole, injecting heated groundwater, biostimulating the system with lactate and bioaugmenting it with a Dehalococcoides containing culture. Solute concentrations were monitored in four observation wells over the course of the test and a non-isothermal reactive transport model, solved in a two-dimensional heterogeneous domain, was developed to quantitatively interpret the experimental observations. The process-based numerical model also allowed evaluating the evolution of chlorinated ethenes concentrations considering different hydraulic, thermal, and operational scenarios. The results demonstrate the beneficial combination of ATES with in situ contaminant bioremediation, showing enhancement of contaminant mass reduction and more complete reductive dechlorination. The developed process-based model can be instrumental for the design and parameterization of pilot and full scale low-temperature ATES-ISB remediation in shallow aquifer systems. • Pilot test of ATES combined with in situ bioremediation in a contaminated aquifer • Numerical model coupling non-isothermal flow, heat and reactive transport • Simulation of pilot test operations and model-based analysis of observations • Temperature-dependent flow, transport and degradation rates of chlorinated ethenes • Scenario simulations to assess the effects of different remediation approaches [ABSTRACT FROM AUTHOR]

Campi Flegrei is a volcanic field located west of Naples (Italy) in a densely populated area. Since 2005, its ground has been rising steadily due to the accumulation of fluids at shallow depths. The inflation of volcanic edifices is a possible precursor of an impending eruption. The uplift is accompanied by increasing seismic activity. This raises concerns about the possibility that the volcano may be on the verge of an eruption. To track the fluid movement, it is possible to monitor subtle changes of velocities of seismic waves by exploring ambient seismic noise. By examining different frequency bands, we can observe velocity changes at different depths. We interpret these changes as a monitoring of depth-dependent deformation in addition to the standard monitoring of surface deformation. We observe a velocity decrease in the long-term trend, presumably due to the extension of the hydrothermal system at shallow depths. To explain the long-term changes, we model a spherical pressure source to simulate volumetric strain changes induced by recent fluid activity. The model explains both, surface and subsurface deformation which leads to the opening of microcracks and pores, resulting in the observed velocity decrease. The short-term velocity changes are mainly driven by temperature or groundwater level changes. Once velocity changes are corrected for seasonal effects, remaining short term velocity changes can be associated with volcanic activity and earthquake swarms. • Monitoring of seismic velocity variations using passive image interferometry. • Long-term velocity change due to volumetric changes of microcracks and pores. • Short-term velocity change due to seasonal temperature and groundwater fluctuations. • Removing seasonal effects reveals short-term velocity changes from volcanic activity. [ABSTRACT FROM AUTHOR]

An alluvial fan is a good area to install open-loop geothermal heat pump (GHP) systems due to shallower aquifers, faster groundwater flow, and fewer land subsidence risks. The natural temperature change in groundwater occurs in alluvial fans due to the recharge of river water and faster groundwater flow, and the thermal impact of the open-loop system has not been studied well in such areas. The purpose of this research is to understand the thermal impact of open-loop GHP systems on an alluvial fan. A regional 3D model of groundwater flow with heat transport was created to determine the distribution of flow velocity and temperature of groundwater. After that, two local models with different groundwater velocities were constructed to demonstrate the thermal impact of an open-loop GHP system using one extraction and one injection well. The results indicated that the local model with faster groundwater flow had a smaller thermal impact. The natural temperature change in groundwater causes groundwater temperature to be lower in the summer and higher in winter during the operation in the local model, with faster groundwater flow. [ABSTRACT FROM AUTHOR]

Temperature is a key factor affecting microbial activity and ecology. An increase in temperature generally increases rates of microbial processes up to a certain threshold, above which rates decline rapidly. In the subsurface, temperature of groundwater is usually stable and related to the annual average temperature at the surface. However, anthropogenic activities related to the use of the subsurface, e.g. for thermal heat management, foremost heat storage, will affect the temperature of groundwater locally. This minireview intends to summarize the current knowledge on reductive dehalogenation activities of the chlorinated ethenes, common urban groundwater contaminants, at different temperatures. This includes an overview of activity and dehalogenation extent at different temperatures in laboratory isolates and enrichment cultures, the effect of shifts in temperature in micro- and mesocosm studies as well as observed biotransformation at different natural and induced temperatures at contaminated field sites. Furthermore, we address indirect effects on biotransformation, e.g. changes in fermentation, methanogenesis, and sulfate reduction as competing or synergetic microbial processes. Finally, we address the current gaps in knowledge regarding bioremediation of chlorinated ethenes, microbial community shifts, and bottlenecks for active combination with thermal energy storage, and necessities for bioaugmentation and/or natural repopulations after exposure to high temperature. [ABSTRACT FROM AUTHOR]

Nano zirconia/zeolite molecular sieve was synthesized by using sodium alginate and FeCl3 as cross-linking agents to produce a bead type adsorbent (Fe@nano ZrO2/ZMS) with improved usability and applicability for nitrate removal. Optimal preparation parameters via mass ratio of nano ZrO2 to ZMS and FeCl3 concentration were determined by batch tests. Best adsorption performance was determined by varying operational adsorption parameters, such as dose (1.0–8.0 g/L), solution pH (3.0–10.0) and co-existing ions (K+, Mg2+, Ca2+, NH4+, Cl−, F−, SO42−, HCO3−). The effect of contact time (10–100 min) and the kinetics of adsorption process were studied using pseudo-first-order, pseudo-second-order, Power and Elovich models starting from different initial concentrations of NO3– ions (20, 30, 50 mg/L, respectively). The Langmuir, Freundlich, Sips and Temkin adsorption models were utilized to describe the equilibrium isotherms. Influence of solution temperature (10–40 °C) and thermodynamics results indicated adsorption was an exothermic and spontaneous process. Maximum removal efficiency of 79.8% occurred at 10 °C which was in line with the actual groundwater temperature. The structural properties were tested by SEM, BET, BJH and N2 adsorption–desorption isotherm. Adsorption mechanism of elements and functional groups on Fe@nano ZrO2/ZMS were studied by EDS, XRD and FTIR. The proposed adsorption mechanism included mostly hydrogen bonding, electrostatic attractions, and ion exchange. After 5 times repeated regeneration by 0.5 mol/L NaHCO3 solution, the beads still showed higher nitrate removal ability. The results showed that Fe@nano ZrO2/ZMS beads can be considered a potentially efficient adsorbent for the removal of nitrate ions from water. [ABSTRACT FROM AUTHOR]

In this study, a Trnsys simulation prediction model for multistage utilization solar-assisted groundwater source heat pump system and a new year-round operation control strategy are proposed. A new dual-interface solar and groundwater heat storage module Type299 was created, which was imported into Trnsys transient simulation model for simulation. A one-year experiment was conducted to test the accuracy of the new model Type299 and Trnsys transient simulation prediction model, taking a case system in the Shenyang area as an example. When the proposed new system and control strategy was applied to the case system, the results showed that the maximum comprehensive performance coefficient of the new system is approximately 4.54, which is 23.8% higher than that of the original system. The annual solar energy utilization of the new system increased by approximately 4.68 × 105 MJ compared with the original system. After 10 years of simulation operation, it was found that the groundwater temperature under the action of the new system was approximately 3.1 °C higher than that of the original system. This effectively alleviates the underground water temperature decrease year by year caused by the operation of the original system. [ABSTRACT FROM AUTHOR]

The outcome of a dimensionless characterization study in a two-dimensional porous media domain in which groundwater flows at a constant horizontal velocity is presented in this report. Using spatial discrimination, the dimensionless groups that govern the solution patterns are determined from dimensionless governing equations. As a boundary condition on the surface, the case of constant temperature is studied. From the mathematical deduction of the groups, a characteristic horizontal length emerges. This length determines the region in which temperature–depth profiles are affected by flow. Existing analytical solutions have been shown to be invalid due to the severe assumption that the horizontal thermal gradient has a constant value. Therefore, universal solutions based on pi theorem have been obtained for the characteristic horizontal length, temperature field, temperature–depth profiles and horizontal temperature profiles. Dependencies between dimensionless groups have been depicted by universal curves, abacuses and surfaces. These graphical solutions are used in an easy way to estimate groundwater velocity from experimental temperature measurements in the form of an inverse problem. In addition, an easy and fast protocol for estimating fluid flow velocity and groundwater inlet temperature from temperature profile measurements is proposed. This protocol is applied in a scenario of groundwater discharge from a quaternary aquifer to a salty lagoon located in the southeast of Spain. [ABSTRACT FROM AUTHOR]

Time series modelling and control of hydrological parameters are the most critical issues in water resources management. The subject matter of this study is finding the significant relationship between natural properties of time series like correlogram and selecting the best combination set of inputs for the fuzzy-neural adaptive network model. In this regard, two different types of the ACF, including sinusoidal and descending shapes, are considered in different climate. Selecting model inputs from the stability range of the ACF diagram for any shape types and model fine tuning lead to inferior results in testing stage. The best R-value of the original temperature and groundwater time series in stability range is 0.2 (|SI|= 1.23, RMSE = 11.91) and 0.2 (SI = 0.14, RMSE = 3.32), respectively. When they choose from the non-stationary range of the ACF, the powerful results for sinusoidal and descending ACF shapes would be achieved. In case, the R-value is more than 94% (|SI|< 0.57, 2.57 < RMSE < 5.5]) and 78% (SI = 0.03 and RMSE = 0.71), respectively. Whether they are picked up from the absolute maximum of ρ value in the ACF diagram, the best model results would have appeared. By applying the inverse of standardization and reforming the shape of the descending ACF to sinusoidal form, R-value is upgraded about 18%, from 78 to 96% the case. Finally, using preprocessing, in particular, standardization on time series does not always lead to improve forecasting model accuracy, but it depends on the shape of the ACF diagram. If it has the sine periodic shape, applying this action leads to poor results. In opposite, by descending ACF shape, using the inverse of standardization can improve the model accuracy in case. Finally, choosing ANFIS model inputs using the ACF diagram and appropriate input sets are more effective than using the model tuning and different fuzzy generators. [ABSTRACT FROM AUTHOR]

Belarusian Potash salt deposits are bedded under aquifers and unstable soil layers. Therefore, to develop the deposits a vertical mine shaft sinking is performed using the artificial ground freezing technology. Nowadays, real-time observations of ground temperature and groundwater level is applied to control the ground freezing process. Numerical simulation can be used for a comprehensive analysis of measurements results. In this paper, a thermo-hydro-mechanical model of freezing for water-saturated soil is proposed. The governing equations of the model are based on balance laws for mass, energy and momentum for a fully saturated porous media. Clausius-Clayperon equation and poroelastic constitutive relations are adopted to describe coupled processes in water and ice pore pressure, porosity and a stress-strain state of freezing soil. The proposed model was used to predict equivalent water content measured in Mizoguchi's test and frost heave in a one-sided freezing test. Numerical simulation of ground freezing in the Petrikov mining complex located in Belarus has shown that the model is able to describe field measurements of pore pressure inside a forming frozen wall. Furthermore, the mismatch between hydro- and thermo-monitoring data obtained during the artificial freezing is analyzed. [ABSTRACT FROM AUTHOR]

Bulqiza chrome mine is one of the most important chromium mines and mining activities in Albania. It is the deepest mine in the Balkans and possibly even in Europe. Recently, the inner shaft of the mine reached a depth of 1000 m, measured from the surface, or -180 m below sea level. Like all deep metal mines, this mine also faces a different set of challenges during its development. The first and most important challenge is that of improving the degree of geological research and knowledge of this mine and assessment of geological resources and reserves according to JORC Code 2012 edition. In addition, a series of other challenges related to increasing the depth of the mine represent the object of this paper: rock and ore stability and the underground voids support; improvement of mining methods and technologies; groundwater and its pumping; temperature, air parameters and mine ventilation. Among other things, these problems were solved using various computation and simulation programs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe2+ in groundwater serves as a sustained catalyst to drive the removal of NH 4 +-N. • High selectivity of NH 4 +-N conversion to N 2 by PMS- Fe 3 O 4 /Cl– system. • Ammonia removed by Cl• − mediated AOPs even under microtherm conditions. • Reliability assessment of NH 4 +-N in-situ removal by PMS-Fe 3 O 4 /Cl– system. The conventional ammonia in-situ treatment technology fails to achieve complete NH 4 +-N degradation, while the high concentration of native iron in groundwater further complicates its removal process, potentially leading to adverse environmental consequences. This study investigates the introduction of peroxymonosulfate (PMS) into groundwater containing high concentrations Fe2+ (Fe 3 O 4 as a ferrous source), which can act as persistent catalysts, and Cl-, causing the degradation of ammonia through chlorine free radical-based advanced oxidation processes (PMS- Fe 3 O 4 /Cl-), and evaluates the advantages and limitations of employing the PMS- Fe 3 O 4 /Cl- system for ammonia treatment. The rapid reaction between SO 4 •- and Cl- resulted in the formation of Cl• as primary products. Cl• initiates a cascade of subsequent reactions with pH-dependent secondary active products. Under optimal conditions, the ammonia removal efficiency reached 97.44 % using the PMS- Fe 3 O 4 /Cl- system within 120 min of operation, which can be attributed to the selective oxidation of ammonia by chlorine reactive species. And this finding was substantiated by observations from experiments involving free radical quenching and EPR spectra coupled with DMPO. The HCO 3 – and humic acid (HA) in water can significantly affect the removal of ammonia, owing to their capability of quenching SO 4 •- and Cl•. Meanwhile, the levels of generated toxic chlorates in our system remain within acceptable limits. The PMS- Fe 3 O 4 /Cl- system exhibited outstanding transport capacity and stability in simulated columns, demonstrating excellent ammonia oxidation efficiency in natural groundwater, thereby confirming its promising practical potential. All experiments were executed at a temperature of 12 ℃, thereby verifying the remarkable efficacy of the PMS- Fe 3 O 4 /Cl- system in removing ammonia even under microtherm conditions. [ABSTRACT FROM AUTHOR]

The production of freshwater represents a prominent global challenge nowadays. One eco-friendly technology to provide clean water even in an adverse environment, with extreme temperatures and scarce groundwater resources is solar-driven water evaporation or solar-to-steam generation. Besides, freshwater can be also extracted from polluted soil or water, purifying the water in the process at the same time. The champion solar-driven water evaporation efficiency is achieved at over 100%. The advancements in photothermal evaporation predominantly prioritize material modification and interfacial heating, with a significant emphasis on optimizing vapor generation efficiency, often neglecting the practical aspect of water collection. By using the right materials, the system can be cost-effective and have a low environmental impact. In this progress report, the latest advancements in natural materials, carbonization of natural materials, hybrid natural materials, and nature-inspired materials are presented. We will delve into their effectiveness in evaporation and their energy efficiency. The review provides suggestions about the compatibility of natural materials for this application and reports on insights into the advancements already accomplished, as well as the remaining opportunities for enhancing the performance of these cost-effective, environmentally friendly, high-performance systems. [Display omitted] • Recent developments of nature-inspired design for solar vapor have been reviewed. • The effectiveness of evaporation and its energy efficiency are discussed. • The suggestions about the compatibility of natural materials are highlighted. • This work reports on insights into the advancements already accomplished. • The crucial challenges in this field are emphasized. [ABSTRACT FROM AUTHOR]

[Display omitted] • Models consider groundwater (GW) inflow, conduction, shading, and other heat fluxes. • Equilibrium temperature deficit concept is used as scenario comparative benchmark. • GW inflow and riparian shading most strongly drive changes in temperature signals. • These scenarios support process-based interpretation of paired air–water metrics. • GW source depth and inflow magnitude affect climate change thermal resilience. Headwater stream temperature often exhibits spatial variation at the kilometer-scale, but the relative importance of the underlying hydrogeological processes and riverine perturbations remains poorly understood. In this study, we investigated the relative importance of groundwater (GW) and other processes on downstream annual stream temperature signal characteristics using deterministic heat budget model (HFLUX) scenarios within an idealized stream reach representative of mountainous forested conditions. We summarized annual stream thermal regimes from the relationship of paired sinusoidal air and water temperature signals (amplitude ratio, phase lag, and mean ratio). Results showed that downstream changes in annual temperature depended on the thermal gradient between water and the hypothetical equilibrium temperature (where all heat fluxes sum to zero). GW inflow, riparian shading, and the boundary input signal were the most significant factors affecting downstream annual water temperature signals, while flow volume and channel dimensions impacted how quickly annual temperature signals changed. Effects of GW were dominated by advective rather than conductive heat exchange processes, but conduction played a larger role when GW input was more spatially diffuse. Our results indicated several mechanisms by which local processes may affect stream thermal resilience to disturbances and can help guide management of wildfire and climate change. [ABSTRACT FROM AUTHOR]

Climate warming has significantly changed the hydrological cycle in cold regions, especially in areas with permafrost or seasonal frost. Groundwater flow and its interactions with surface water are essential components of the hydrological process. However, few studies or modeling works have been based on long-term field observations of groundwater level, temperature, hydrogeochemistry, or isotopic tracers from boreholes due to obstacles such as remote locations, limited infrastructure, and harsh work conditions. In the Hulugou catchment, an alpine catchment in the headwater region of the Heihe River on the northern Qinghai–Tibet Plateau (QTP), we drilled four sets of depth-specific wells and monitored the groundwater levels and temperatures at different depths. Surface water (including river water, glacier meltwater, and snow meltwater), precipitation, groundwater from boreholes, spring water, and soil water were sampled to measure the abundances of major and minor elements, dissolved organic carbon (DOC), and stable and radioactive isotopes at 64 sites. This study provides a dataset of these groundwater parameters spanning 6 consecutive years of monitoring/measurements. These data can be used to investigate groundwater flow processes and groundwater–surface water interactions on the QTP under global climate change. The dataset provided in this paper can be obtained at 10.5281/zenodo.6296057 (Ma et al., 2021b) and will be subject to further updates. [ABSTRACT FROM AUTHOR]

Accurate monitoring and controlling of the temperature in the combustion chamber can raise the burner efficiency, combustion intensity, fuel consumption and reduce pollutant emission. However, except combustion is accurately monitored and controlled, high concentration of pollutant gases and products like carbon monoxide (CO) and soot can form in the combustion chamber. This paper compares the combustion thermal profiles in a liquid fuel swirl burner using developed straight edge and curve edge blade swirlers at (20, 30, 40, 50 and 60)° for 6, 8, 10 and 12 number of blades in order to optimize the temperature of the burner. Measurements were made in straight and curve blades liquid fuel swirl burner in order to study and compare the thermal characteristics of the straight and curve edge blades in optimizing the combustion dynamics. Similarly, measurements were made for burner without swirl generator and the combustion temperature assessed. Thermal profile was measured in the direction of flow via the six axial ports at distance ((d) = 150, 350, 550, 750, 950 and 1150 mm) from the burner exit using Chromium-Zinc thermocouple. Results showed that the wavelength and oscillation of temperature decay in the same type of blade followed the same trend and the peak of combustion intensity is nearer the nozzle for curve edge blades than the straight edge blade. Six (6) blades performed best with the highest temperature in all the ports, while 12 blades gave the least performance. Findings further show that curve edge blade swirlers gave better performance than straight edge blade swirlers with highest temperature of (1065 and 1015) °C, respectively. Hence, it is recommended especially where high temperature and stability application is desirable. [ABSTRACT FROM AUTHOR]

This paper discusses the application of Fresnel Lens Concentrator for Solar Water Heater which is a case study in Indonesia. The purpose of this study was to find an empirical equation of the relationship between Direct Normal Irradiance (Ib) and focal point temperature (Tf). The research location is Latitude: 7.9553 °S and Longitude: 112.6145 °E. The SM-206 solar power meteris used. The Fresnel lenses are made of PMMA material. Its specifications are: diameter = 1000 mm; weight = 2 kg; thickness = 2 mm; groove pitch = 0.5 mm and focal length = 880 mm. The main experimental setup consists of a PMMA Fresnel lens and a receiver. The conical cavity receiver has specifications; geometric concentration ratio, CRg = 8, and V = 2 Liters. Temperature measurement is done using a temperature data acquisition system. The K-type thermocouple is used to measure: 1) ambienttemperature (Ta); 2) the focal point temperature (Tf); 3) receiverwall temperature (Tr); 4) watertemperature (Tw). The experiment obtained the results of the empirical equation for the relationship between Direct Normal Irradiance (Ib) and focal point temperature (Tf). The increase in solar radiation produces a focus temperature, exponentially. At DNI 858 W/m2 it can produce a focal temperature of up to 1064 °C. The efficiency of the receiving cavity of the thermal cone which contains 2 litres of water and CRg = 8 under conditions of relatively Direct Normal Irradiance (Ib = 675 W/m2) is about 10.61 %. Furthermore, the energy that can be generated in heating water is 0.17-0.32 MJ, in 100 minutes. Heat convection and radiation loss can be reduced by adding an insulating layer to the walls and coating the surface with black. [ABSTRACT FROM AUTHOR]

Peatlands are shaped by slow litter decomposition, but threshold decomposition rates that allow peat formation remain unclear. Can agroforestry in the tropics be compatible with paludiculture that allows peat formation? We explored the determinants of litter decomposition in wet agroforests adjacent to tropical peatlands in Central Kalimantan (Indonesia) by litterbag studies (up to 16 weeks) with standing litter sources to estimate rate constants, characterize litter quality (especially lignin (L), polyphenolics (Pp) and nitrogen (N)), and monitor temperature and groundwater levels. In litter transfer experiments we tested for home-field advantage (HFA) effects between land cover types. Mean residence times around 85 weeks at 27 °C were associated with a high (L + Pp)/N ratio. However, in the crossover treatments, mean residence times varied from 30 to 180 weeks and strong HFA effects (up to 80% faster decomposition at "home") were found when litter from other sources was tested in old fruit-based agroforests. HFA indicates a local decomposer community well-adapted to its normal litter diet. Litter residence times of around two years are below the apparent peat formation threshold. Maintaining wet agroforest conditions adjacent to peat domes supports peatland rewetting and restoration but does not contribute to on-site peat formation processes. [ABSTRACT FROM AUTHOR]

The assessment of groundwater and surface water interactions is a current topic, because research of the issue can contribute to a better understanding of the dynamics of the natural environment. Numerical modelling is a suitable tool for solving surface and groundwater interactions. Through modelling, it is possible to simulate the ongoing processes in the area under study and create a hydraulic and heat transport model. The Sihoť Water Source was chosen as the area of study because it is an anthropogenically unaffected locality. During the compilation of the model and later in the calibration process, data on the temperature and level of the groundwater table and Danube water were used, which were available thanks to the monitoring that took place at the site. In the calibration process, the sensitivity of the parameters determined by calibration was also examined. During calibration and sensitivity analysis, the hydraulic conductivity was further investigated using so-called pilot points that had been entered into the model. The accuracy of the model was verified by automatic calibration using the PEST program, while the average error value was 0.21 m for the hydraulic model and 1.04 °C for the transport model. The knowledge and methodological procedures gained by examining the issue can be applied in many other cases, such as water quality analysis, assessment of the vulnerability of the groundwater and surface water regime, or in assessing the impact of extreme precipitation and other factors. [ABSTRACT FROM AUTHOR]

Abstract—The last activation of the Koryakskii volcano in 2008–2009 was accompanied by intense fumarolic and seismic activity. Volcanic activity peaked in March–April 2009 when ash plume rose to a height of 5.5 km and extended laterally over more than 600 km. To understand the dynamics of the volcanic processes and to forecast the further course of the events, it is relevant to establish whether the eruption was associated with a rise of magma to beneath the volcanic edifice or caused by fracturing of the volcano's basement and penetration of groundwater into a high temperature zone. Based on the analysis of the images from the Japanese satellite ALOS-1 using satellite radar interferometry methods, the slope displacements of the Koryakskii volcano during its last activation have been estimated for the first time. The displacements reach 25 cm and cannot be explained by the formation of a layer of volcanic ash deposits or by the slope processes. The most likely cause of the displacements should be recognized to be the intrusion of magmatic material into the volcano edifice with the formation of a fracture with its lower edge at a depth of 0.5 km above sea level, with a size of 1.0 and 2.4 km along the strike and dip, respectively, and with a dip angle from 45° to 60°. Therefore, the processes taking place beneath the volcano can be threatening to the nearby localities and infrastructure and require continuous monitoring. [ABSTRACT FROM AUTHOR]

Groundwater samples from five rural agricultural villages within the Anambra basin of southeastern Nigeria were selected for the determination of their drinking quality, hydrogeochemical characteristics, corrosivity and scaling potentials. The groundwater temperature ranged from 10 to 31 °C. The pH measurements revealed that the samples are acidic. Parameters such as total dissolved solids, electrical conductivity, magnesium, calcium, sodium, chloride, bicarbonate, sulfate and nitrate recorded scores within their respective standard limits. However, potassium and phosphate pollution was observed in some samples. Synthetic pollution index was used to summarize the drinking water quality of the samples. The results showed that 88% of the samples were moderately polluted while 12% were highly polluted. Thus, the results show that they have questionable drinking water quality. Several indices used for corrosivity and scaling analyses indicated that, although the samples pose low risk of scaling (encrustation), they are severely aggressive. Hence, they are likely to deteriorate metallic water storage and distribution facilities in the study area. The predominant water facies are Cl·SO4–Ca·Mg and Cl·SO4–Na·K. Multiple hydrogeochemical and chemometric analytical models were integrated to better unravel and understand the geochemical history, processes and evolution of the groundwater. All of the models used jointly indicated that mixed, multiple processes, namely mineral-rock weathering, ionic exchange processes and anthropogenic inputs, are responsible for the predominant hydrogeochemistry observed in the study area. However, in this regard, natural, geogenic processes were identified as more important factors than those from anthropogenic activities. [ABSTRACT FROM AUTHOR]

Burrowing crayfish represent 15% of total crayfish species and 32% of imperilled species. Few life history studies exist for these species and more information is needed regarding their ecology, population status, distribution, and biogeography for effective conservation efforts. Challenges to gaining such information include sampling difficulty and small sample sizes. Collection efforts may be more efficient if activity patterns can be identified for species of interest. The goal of our study was to assess specific environmental indicators of burrowing crayfish activity patterns.We evaluated activity patterns of two primary burrowing crayfish species, Lacunicambarus erythrodactylus (Simon & Morris, Proc. Biol. Soc. Wash., 127, 2014, 572) and Procambarus holifieldi (Schuster, Taylor, & Adams, Zootaxa, 4021, 2015, 1) using laser‐triggered digital photography for one‐year periods in the Bogue Chitto Creek floodplain, Dallas County, Alabama, U.S.A. We predicted that activity would be related to time of day, season, groundwater depth, and precipitation.Activity by L. erythrodactylus covaried significantly with time of day, daylength, groundwater temperature, and relative air temperature, while activity by P. holifieldi covaried with time of day, season, groundwater temperature, and relative air temperature. Additionally, burrow chimney construction by P. holifieldi covaried with daylength, groundwater temperature, relative air temperature, and precipitation.Out‐of‐burrow activity for both species was greatest at night and during periods of relatively cool groundwater temperatures and relatively warm air temperatures, which may be linked to thermal regulation behaviour. The probability of chimney construction by P. holifieldi increased with increasing daylength and decreasing precipitation and was highest during periods of cool groundwater temperatures and air temperatures. A distinct lull in activity from October through March for both species was likely to be the result of reproductive behaviours such as period of egg production and incubation within burrows.Identifying peak out‐of‐burrow activity periods for burrowing crayfish will allow collection efforts to be focused on periods of greatest activity, thereby facilitating the study of burrowing crayfish behaviour. [ABSTRACT FROM AUTHOR]