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Objective: In a changing climate, the effects of air temperature, precipitation, and groundwater on water temperature and thermal habitat suitability for Gulf Sturgeon Acipenser desotoi, listed as threatened under the U.S. Endangered Species Act, are not well understood. Hence, we incorporated these factors into thermal habitat models to forecast how Gulf Sturgeon may be affected by wide‐ranging climate change scenarios in 2024–2074. Methods: Using data from the Choctawhatchee River, Florida, we developed precipitation‐ and groundwater‐corrected air–water temperature models, compared their accuracy with that of conventional air–water temperature models used in fisheries management, and projected future Gulf Sturgeon thermal habitat suitability for normal physiological functioning and fieldwork (i.e., population sampling and telemetry surgeries) in summer (May–August) under 16 climate change scenarios. Result: Precipitation‐ and groundwater‐corrected models were more accurate than conventional air–water temperature models (mean improvement in adjusted R2 = +0.45; range = +0.09 to +0.75). Water temperature was projected to warm at widely variable rates across climate change scenarios encompassing different air temperature, precipitation, and groundwater regimes. Importantly, Gulf Sturgeon summer aggregation areas were cooler and influenced more by precipitation and groundwater and less by air temperature than were non‐aggregation areas. If precipitation and groundwater—as drivers of cooling—become warm in a changing climate, summer aggregation areas were projected to exhibit thermal habitat degradation equivalent to or greater than that of non‐aggregation areas. Conclusion: Our results add hydrological context to the premise that aggregation areas provide cool water and energetic savings for Gulf Sturgeon during summer, underscoring the importance of protecting these habitats through groundwater conservation, water quality monitoring, and riparian/watershed habitat management. Our findings indicate that identifying thermally appropriate times for fieldwork activities will be increasingly important and time‐restricted as climate change intensifies. However, our research provides managers with a portfolio of water temperature models and an accurate, cost‐effective, management‐relevant approach to forecasting thermal habitat conditions for Gulf Sturgeon and other species in a changing climate. Impact StatementWater temperature models with precipitation and groundwater are accurate and useful, allowing managers to locate key thermal habitats, forecast temperatures, and decide when and where to safely target, capture, tag, and monitor Gulf Sturgeon and other species amid climate change. [ABSTRACT FROM AUTHOR]

Restoring groundwater flow is a management option that improves water temperature regimes and benefits fishes. Although this strategy applies more readily to river systems, the thermal character of reservoirs is heavily influenced by inflowing rivers. We examined differences in age, structure, and growth of both Freshwater Drum Aplodinotus grunniens and Gizzard Shad Dorosoma cepedianum that occupy catchments with varying groundwater contributions in the south‐central United States. Seepage run data indicated that the Kiamichi River was losing surface water to groundwater in summer 2016, whereas groundwater inflows were apparent in the Elk River basin. Summer 2016 data showed that the Elk River had cooler water temperatures than the Kiamichi River and Grand Lake O' the Cherokees water temperatures were similar to those in the incoming Elk River. We found higher densities of older Freshwater Drum and Gizzard Shad (maximums of 32 and 8 years old, respectively) in samples from the Grand basin than among fish that were sampled from the Kiamichi River basin (21 and 6 years old, respectively). Freshwater Drum grew at similar rates in both basins even though they reached larger maximum lengths in the Grand basin (649 mm TL) than in the Kiamichi River basin (600 mm). The average asymptotic length was greater for the Kiamichi population (L∞ = 613 mm) than for the Grand population (L∞ = 557 mm). Gizzard Shad from the Grand basin were larger than those from the Kiamichi River basin, though the latter population grew faster initially (Brody growth coefficient: K = 0.787 versus K = 0.179, respectively), but they had smaller asymptotic length (L∞ = 206 mm versus L∞ = 343 mm). The role that groundwater plays in temperature regulation in these basins partially explains the observed differences. Our results suggest that the metabolic theory of ecology can be applied to fisheries management at a finer spatial scale. [ABSTRACT FROM AUTHOR]

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Abstract Ground source heat pump (GSHP) systems have been considered to be a low-carbon technology to provide heating and cooling for buildings in urban environments. This study focuses on the short-and long-term evolution of groundwater temperature induced by high-density GSHP installations in an urban residential area in Cologne, Germany. Specifically, a 2D heat transport model considering both thermal convection and conduction has been constructed using the finite element simulator OpenGeoSys. The simulated temperature changes within the initial few years were compared to the monitored dataset, while the GSHP heating load and thermal conductivity were calibrated. Subsequently, the validated model was run for 25 years to evaluate the long-term trend of the subsurface temperature. Also, effects of model uncertainties were explored with different simulated scenarios. Results indicate that sufficiently large groundwater flow and a high cooling ratio can effectively mitigate ground cooling. Based on these findings, best and worst-case scenarios were formulated for the studied case and the sustainability of GSHP operation were evaluated accordingly. As an outcome, specific design and operation criteria were proposed for the sustainable utilization of shallow geothermal energy for the heating and cooling of buildings in urban areas. [ABSTRACT FROM AUTHOR]

The groundwater heat pump system is a new clean energy technology. Its attractive advantages of high efficiency, environmental friendliness and energy conservation had made itself favored by people. But there exist some problems in the application as well. The “heat transfixion” is one of the main reasons that hinder the promotion of groundwater heat pump technology. In this paper, we use a finite element program to establish groundwater heat transport model based on the assumption of some basic conditions, using numerical simulation method to study groundwater temperature field evolution on a GWHP system in Shenyang, trying to find the scope of “heat transfixion”. [ABSTRACT FROM AUTHOR]

An aerobic granular biofilm process was operated in a sequential batch reactor for treating nitrate-pollute groundwater at 6 ºC, which was fed with a progressively reduced carbon concentration to understand the nitrate removal efficacy in cold regions by denitrifying microorganisms. The evaluation of the performance reflected a quick granulation promoted by hydraulic stress and a high organic loading rate (OLR). The granules were dense and compact and kept stable conformation until the end of operation, despite the low temperature. Nitrate removal in the stage with high OLR was close to 100%, while the stage with the lowest OLR reached efficiencies higher than 87% in steady-state, suppose a successful advantage against other biological processes for treating drinking water. The bacterial community in the mature granules were colonized by cold-adapted microorganisms such as Holophagaceae and Candidatus Microthrix. Methanospirillum and Bathyarchaeota were the most abundant archaeal phylotypes, which showed a more stable consortium and Nectriaceae and Trichosporonaceae were the most dominant fungal phylotypes for all stages. The qPCR revealed that the crucial role was played by Fungi and Bacteria , while Archaea lost abundance in granular biomass, despite extreme conditions. Aerobic granular sludge is a robust biological technology able to remove nitrate in oligotrophic waters bodies. • Aerobic granular biomass was used to treat nitrate-polluted groundwater. • Nitrate removal ratio was success under low ORL at low temperature. • Holophagaceae and Candidatus Microthrix proliferated in granular biomass. • qPCR revealed the key role of Fungi and Bacteria in denitrification and granulation. [ABSTRACT FROM AUTHOR]

Mixed metal-oxides are an important class of materials studied for the adsorptive removal of contaminants in water. However, the lack of affordable and versatile immobilisation techniques limits its large-scale deployment in water purification. The present work describes the use of protonated chitosan as a template and reinforcing agent to fabricate FeOOH-Mn x O y bimetal-oxide granules formed via complexation of metal-oxides with hydroxyl and amine groups in chitosan. The synthesis procedure also enables the modulation of nanocomposite into granules of different shapes and sizes. XRD and XPS analyses confirm the existence of MnO, Mn 2 O 3 , MnO 2 , and FeOOH phases in the composite. The granules showed excellent affinity to scavenge the model pollutant, Pb2+, through inner-sphere complexation with an estimated Sips isotherm capacity of 108.12 mg/g. The chemical stability analysis of the composite showed that the leaching of Fe and Mn from the composite is pH, contact time, and temperature dependent. The background ions can also affect the chemical stability of the composite. However, Fe and Mn leaching were well within the permissible limit under typical groundwater pH and temperature. There is no significant effect on Pb2+ intake by competing ions such as Cl-, NO 3 -, HCO 3 -, Ca2+, Fe2+, and Mn2+. In short, the improved adsorption capacity, the ability to form hydraulically stable granules, and ease of synthesis make the composite a practical adsorbent for removing heavy metal ions in water. [Display omitted] • Less energy-intensive and versatile approach for synthesis and granulation of bimetal-oxides nanocomposite. • Hydraulically and chemically stable bimetal-oxides granules with tunable size and shape. • A granular FeOOH-MnxOy composite with a Pb2+ adsorption capacity of 108.12 mg/g. • Studied the effect of water quality parameters on the chemical stability of FeMnG. [ABSTRACT FROM AUTHOR]

Abstract: Many subsurface waters are considered groundwater but are influenced in shallow depths by hyporheic, parafluvial and/or soil interception water to such a degree that groundwater fauna (stygofauna) communities may be significantly altered. Recharge, even if spatially and temporally distinct, delivers input of dissolved oxygen, organic matter (OM), and nutrients that caters sustainably for ubiquists such as stygophiles and hyporheic fauna, but renders the life of uncompetitive stygobites difficult or impossible. The impact of recharge at shallow groundwater thus needs to be taken into account when determining groundwater fauna reference communities and when evaluating monitoring studies. One of the main characteristics of groundwater is low OM concentration. In contrast, high OM concentrations are typical of hyporheic or parafluvial waters, which are enriched by OM from the river, the riparian soils and from interflow, and which contribute significantly to river OM balance. Consequently, for ecological studies on subsurface waters, both the origin of the water and OM, and the intensity of surface water interactions should be considered. Here, we discuss how groundwater spatial and temporal heterogeneity translates into faunal distribution patterns. In terms of the origin of water and OM, and from an ecological point of view, we need to distinguish between (i) shallow groundwater characterized by infiltrating precipitation and soil recharge, (ii) shallow groundwater interacting with surface water bodies such as continuously flowing and ephemeral streams and rivers, and (iii) “old” groundwater which has no recent connections to the surface and is thus largely secluded from input of nutrients and carbon. Water in the first two groups is characterized by high amounts of OM of varying quality, while water in the third group is characterized by low amounts of low quality OM. Consequently, stygophiles dominate in groups 1 and 2, with hyporheic fauna taking up a considerable proportion in group 2, while stygobites only dominate in group 3. Thus, for studies aiming to assess impacts on groundwater, only sampling sites of the third group should be used for reference sites as these are the most likely sites to have little surface impact and a stygofauna representative of the deeper aquifer. [Copyright &y& Elsevier]

Abstract: The Mornag coastal groundwater underlies the plain of this region. It is in northern Tunisia and 20km SW of Tunis City. This region is known for its important agricultural activity. This aquifer is the main groundwater resource of the department of this region. To limit the overexploitation, there is a creation of some perimeters in the Naasen and Irrisala localities where wastewater is used. To maintain the hydrostatic groundwater balance, freshwater is injected (artificial refill). In the Nassen area treated wastewater irrigation is slowed and then stopped while the Irrisala perimeter is still irrigated by the same water type. To maintain hydrostatic equilibrium of the aquifer, water from the Méjerda Canal (M.C.) was injected. A geochemical study of the different parts of this groundwater is carried out, in order to clarify the salinisation origin and the hydrochemical evolution of the Mornag groundwater and to estimate the possible relationships between the natural processes (marine water intrusion), the water quality used either for irrigation or for artificial refill, and the geologic environment on the water quality of this aquifer. Its salinity, pH, temperature and electrical conductivity were measured and their respective averages are 3.1g/l, 7.4, 18.7°C and 4.4mS/cm. The concentrations of sodium, calcium, magnesium, bicarbonate, chloride, sulphate, potassium and bromides were measured and their respective averages are 29.0, 15.1, 10.9, 4.8, 26.8, 10.5, 0.3 and 0.0482mg/l. rMg2+/rCa2+ and rBr−/rCl− ratios were calculated. The results suggest that the Mornag groundwater can be divided into 4 areas where the water chemistry depends on the natural processes and the water quality used for irrigation and artificial recharge: [-] for the coastal zone, marine water infiltration provokes the increase in salinity of this part of the aquifer; [-] infiltration of wastewater used for irrigation and run-off water resulted in changing geochemical water quality of these aquifer areas; [-] stopping of the use of wastewater, irrigation and artificial recharge water with good water quality did improve the aquifer water quality. [Copyright &y& Elsevier]

• Fundamentals in modeling of buried TES in groundwater environment. • Development of 3-D models for buried hot-water tanks and pits with groundwater flow. • Cross-validation of TES model against FEFLOW. • Understanding the groundwater impact on large-scale TES planning and construction. • Protective measures restricting impact on groundwater and improving TES efficiency. In view of the urgent need for energy efficiency measures, renewables-based district heating (R-DH) can prove an efficient approach to meet the heating demand in cities whereby locally-available renewable resources are exploited. Yet, the renewables experience intermittency, which might lead to seasonal mismatch between heat supply and demand. Therefore, large-scale seasonal thermal energy storage (STES) systems are often envisioned as key elements in R-DH. Given their large volumes, these systems are often installed underground whereby groundwater tables are expected to lead to twofold impacts due to the TES-groundwater interaction. This work reports the development of models for the planning and optimization of STES and, then, conducts a calibration study to attain credibility in the models. Next, it examines the planning of STES under such unfavorable hydrogeological conditions whereby a groundwater flow is anticipated. The results indicate that Darcy flow plays a significant role in increasing the thermal losses that result in increasing groundwater temperature. Therefore, it becomes crucial to provide protective measures to maintain acceptable groundwater quality prescribed by national standards. Hence, the work investigates the role of cut-off wall distance and TES insulation quality to mitigate the TES thermal losses, increase the TES efficiency and reduce the groundwater temperature. [ABSTRACT FROM AUTHOR]