To date, there has been no agreement on the best way to simulate saltwater intrusion (SWI) in karst aquifers. An equivalent porous medium (EPM) is usually assumed without justification of its applicability. In this paper, SWI in a poorly karstified aquifer in Lebanon is simulated in various ways and compared to measurements. Time series analysis of rainfall and aquifer response is recommended to decide whether quickflow through conduits can be safely ignored. This aids in justifying the selection of the exemplified EPM model. To examine the improvement of SWI representation when discrete features (DFs) are embedded in the model domain, the results of a coupled discrete-continuum (CDC) approach (a hybrid EPM-DF approach) are compared to the EPM model. The two approaches yielded reasonable patterns of hydraulic head and groundwater salinity, which seem trustworthy enough for management purposes. The CDC model also reproduced some local anomalous chloride patterns, being more adaptable with respect to the measurements. It improved the overall accuracy of salinity predictions at wells and better represented the fresh–brackish water interface. Therefore, the CDC approach can be beneficial in modeling SWI in poorly karstified aquifers, and should be compared with the results of the EPM method to decide whether the differences in the outcome at local scale warrant its (more complicated) application. The simulation utilized the SEAWAT code since it is density dependent and public domain, and it enjoys widespread application. Including DFs necessitated manual handling because the selected code has no built-in option for such features.

Among the advances made in analytical and numerical analysis methods to quantify groundwater/surface-water interaction, one methodology that stands out is the use of heat as an environmental tracer. A large data set of river and riverbed temperature profiles from the Aa River in Belgium has been used to examine the spatial-temporal variations of groundwater/surface-water interaction. Exchange fluxes were calculated with the numerical heat-transport code STRIVE. The code was applied in transient mode to overcome previous limitations of steady-state analysis, and allowed for the calculation of model quality. In autumn and winter the mean exchange fluxes reached −90 mm d⁻¹, while in spring and early summer fluxes were −42 mm d⁻¹. Predominantly gaining conditions occurred along the river reach; however, in a few areas the direction of flow changed in time. The river banks showed elevated fluxes up to a factor of 3 compared to the center of the river. Higher fluxes were detected in the upstream section of the reach. Due to the influence of exchange fluxes along the river banks, larger temporal variations were found in the downstream section. The exchange fluxes at the river banks seemed more driven by variable local exchange flows, while the center of the river was dominated by deep and steady regional groundwater flows. These spatial and temporal differences in groundwater/surface-water exchange show the importance of long-term investigations on the driving forces of hyporheic processes across different scales.

The modeling of changes in surface water and groundwater in the areas of inter-basin water diversion projects is quite difficult because surface water and groundwater models are run separately most of the time and the lack of sufficient data limits the application of complex surface-water/groundwater coupling models based on physical laws, especially for developing countries. In this study, a distributed surface-water and groundwater coupling model, named the distributed time variant gain model–groundwater model (DTVGM-GWM), was used to assess the influence of climate change and inter-basin water diversion on a watershed hydrological cycle. The DTVGM-GWM model can reflect the interaction processes of surface water and groundwater at basin scale. The model was applied to the Haihe River Basin (HRB) in eastern China. The possible influences of climate change and the South-to-North Water Diversion Project (SNWDP) on surface water and groundwater in the HRB were analyzed under various scenarios. The results showed that the newly constructed model DTVGM-GWM can reasonably simulate the surface and river runoff, and describe the spatiotemporal distribution characteristics of groundwater level, groundwater storage and phreatic recharge. The prediction results under different scenarios showed a decline in annual groundwater exploitation and also runoff in the HRB, while an increase of groundwater storage and groundwater level after the SNWDP’s operation. Additionally, as the project also addresses future scenarios, a slight increase is predicted in the actual evapotranspiration, soil water content and phreatic recharge. This study provides valuable insights for developing sustainable groundwater management options for the HRB.

In Northern China, karst systems in widely distributed carbonate rocks are one of the most important water supplies for local inhabitants. Constrained by the specific geological and geomorphological conditions, most karst water in this region is discharged as individual or groups of springs. This paper summarizes the characteristics, chemistry, and environmental quality of these karst systems in Northern China. Five structural models of karst water systems were identified based on the relationships between the karst geological strata and karst groundwater flow fields. These specific structural models may closely relate to the attendant environmental geological issues and consistent risks from pollution. Over the past 40 years, the karst water systems in Northern China have suffered from various environmental problems, including deteriorating water quality, the drying up of springs, a continuous decline in the level of karst water, and so on. Based on the field investigation and previous data, a preliminary summary is provided of the environmental problems related to the development and evolutionary trends of karst water in this region. The results highlight the significant challenges associated with karst water, and it is essential that all segments of society be made aware of the situation in order to demand change. In addition, the study provides a scientific basis for the management, protection, and sustainable utilization of karst water resources.

L’aigua del mar és rica en esperma de meduses. Aquesta és una de les conclusions d'un estudi que publica la revista Scientific Reports, realitzat per biòlegs de l'Institut de Biologia Evolutiva (IBE-CSIC-UPF) i de l'Institut de Ciències del Mar (ICM-CSIC). La proporció del material genètic de l'esperma és especialment abundant (un 33%) en les mostres d'aigua amb absència d'oxigen. El mateix estudi ha confirmat que almenys el 85% dels microorganismes que viuen al mar encara són desconeguts | Peer reviewed

A study in eastern Taiwan evaluated the importance of montane water contribution (MC) to adjacent valley-plain groundwater (VPG) in a tectonic suture zone. The evaluation used a ternary natural-tracer-based end-member mixing analysis (EMMA). With this purpose, VPG and three end-member water samples of plain precipitation (PP), mountain-front recharge (MFR), and mountain-block recharge (MBR) were collected and analyzed for stable isotopic compositions (δ²H and δ¹⁸O) and chemical concentrations (electrical conductivity (EC) and Cl⁻). After evaluation, Cl⁻ is deemed unsuitable for EMMA in this study, and the contribution fractions of respective end members derived by the δ¹⁸O–EC pair are similar to those derived by the δ²H–EC pair. EMMA results indicate that the MC, including MFR and MBR, contributes at least 70% (679 × 10⁶ m³ water volume) of the VPG, significantly greater than the approximately 30% of PP contribution, and greater than the 20–50% in equivalent humid regions worldwide. The large MC is attributable to highly fractured strata and the steep topography of studied catchments caused by active tectonism. Furthermore, the contribution fractions derived by EMMA reflect the unique hydrogeological conditions in the respective study sub-regions. A region with a large MBR fraction is indicative of active lateral groundwater flow as a result of highly fractured strata in montane catchments. On the other hand, a region characterized by a large MFR fraction may possess high-permeability stream beds or high stream gradients. Those hydrogeological implications are helpful for water resource management and protection authorities of the studied regions.

Geothermal resources are practical and competitive clean-energy alternatives to fossil fuels, and study on the recharge sources of geothermal water supports its sustainable exploitation. In order to provide evidence on the recharge source of water and circulation dynamics of the Tangshan Geothermal System (TGS) near Nanjing (China), a comprehensive investigation was carried out using multiple chemical and isotopic tracers (δ²H, δ¹⁸O, δ³⁴S, ⁸⁷Sr/⁸⁶Sr, δ¹³C, ¹⁴C and ³H). The results confirm that a local (rather than regional) recharge source feeds the system from the exposed Cambrian and Ordovician carbonate rocks area on the upper part of Tangshan Mountain. The reservoir temperature up to 87 °C, obtained using empirical as well as theoretical chemical geothermometers, requires a groundwater circulation depth of around 2.5 km. The temperature of the geothermal water is lowered during upwelling as a consequence of mixing with shallow cold water up to a 63% dilution. The corrected ¹⁴C age shows that the geothermal water travels at a very slow pace (millennial scale) and has a low circulation rate, allowing sufficient time for the water to become heated in the system. This study has provided key information on the genesis of TGS and the results are instructive to the effective management of the geothermal resources. Further confirmation and even prediction associated with the sustainability of the system could be achieved through continuous monitoring and modeling of the responses of the karstic geothermal reservoir to hot-water mining.

La pasantia en mención se realiza en el marco del programa manos a la paz-estado joven el cual busca fortalecer las capacidades de construcción de paz en territorios golpeados por el conflicto armado en Colombia, mediante la participación de estudiantes universitarios y profesionales mediante el apoyo a sectores claves como medio ambiente, reparación del tejido social, convivencia, paz, agua potable y saneamiento básico, entre otros. Ademas fomentando el desarrollo de practicas laborales de estudiantes de entidades publicas. Se desarrollan las actividades como ingeniero pasante en la Alcaldía Municipal de Buenos Aires en el departamento del Cauca, desde la Secretaria de Planeación e Infraestructura. El objetivo general de la pasantía era, apoyar la Secretaria de Planeación de Buenos Aires, Cauca, de acuerdo al plan de desarrollo municipal, aportando los conocimientos en el área de acción de ingeniería sanitaria que contribuyan a la construcción de la paz y el desarrollo territorial. Por lo que finalmente este objetivo central se cumple mediante el apoyo a la formulación de los Programas de Desarrollo con Enfoque Territorial - PDET, elaborando proyectos de alcantarillado y control de aguas residuales, realizando seguimiento y control de las obras de instalaciones sanitarias, y asesorando a las juntas administradoras de acueducto en el municipio. | The mentioned internship is carried out within the framework of the manos a la paz-estado joven program, which seeks to strengthen the capacity for peacebuilding in territories hit by the armed conflict in Colombia, through the participation of university students and professionals through support for key sectors such as the environment, repair of the social fabric, coexistence, peace, potable water and basic sanitation, among others. Also promoting the development of work practices of students in public entities. The activities are developed as an intern engineer in the city hall of Buenos Aires in the department of Cauca, from the Secretariat of Planning and Infrastructure. The general objective of the internship was to support the Secretary of Planning of Buenos Aires, Cauca, according to the municipal development plan, providing knowledge in the area of ​​action of sanitary engineering that contribute to the construction of peace and territorial development . So finally this central objective is met by supporting the formulation of Development Programs with Territorial Approach -PDET, drafting sewage and wastewater control projects, monitoring and controlling the works of sanitary facilities, and advising the administrative boards of aqueduct in the municipality. | Manos a la paz | Estado joven | Ministerio de Trabajo | Departamento Administrativo de la Función Pública

Well ageing is mostly caused by mechanical and biogeochemical clogging processes, which affect the gravel pack, screen slots and casing. Clogging deposits increase head losses due to a constriction of the hydraulically effective area. For this study, clogging is mimicked by systematically reducing the gravel pack porosity, the screen open area and the nominal inner casing diameter. Groundwater flow velocity strongly increases close to the well, inducing inertial and turbulent flow components. Therefore, gravel pack head losses were calculated using the Forchheimer-Engelund equation, in conjunction with the Kozeny-Carman equation, which relates gravel pack porosity and hydraulic conductivity. Screen losses were assessed using the Orifice equation and turbulent casing losses with the Darcy-Weisbach equation. For the settings chosen here, a dramatic increase of head losses occurs when the clogging has reduced the effective porosity in the gravel pack by ~65%, the open area of the screen by ≥98%, and the casing diameter by ~50%. Since the latter two conditions are rarely reached in actual wells, the clogging of the gravel pack is the decisive parameter that controls well ageing. Regular monitoring of the well yield is therefore needed, since processes in the gravel pack are difficult to track directly. Unlike the deposits on the casing and in the screen slots, obstructions in the gravel pack are much more difficult to remove.

ABSTRACT - In this study we propose to improve both, the quality and its repetition in time of Tannat wine, through soil management aimed at increasing the potential control of vine water availability. A change in the current grape-growing paradigm was proposed, where the strategy in non-irrigated vineyards is to avoid competition with the cover crops through herbicide applications accepting unpredictable periods of water deficit or excess..-.-.-.-.-.-.-.-.RESUMEN - El estudio se orienta a la mejorar de la calidad y regularidad del producto vino Tannat, a traves de un manejo del suelo orientado a aumentar el control potencial de la disponibilidad hídrica del viñedo. Se plantea un cambio en la "lógica productiva actual", donde en una viticultura en secano, se busca preservar el agua del suelo mediante la eliminación de competencia a traves de la aplicación de herbicidas bajo la fila de plantación (H), aceptando los impredecibles periodos de déficit y exceso hídrico..-.-.-.-.-.-.-.-.-.RIASSUNTI - In questo studio ci proponiamo di migliorare sia la qualità e la sua ripetizione nel tempo del vino Tannat, attraverso la gestione del suolo volta ad aumentare il potenziale controllo della disponibilità di acqua di vite. Viene proposto un cambiamento nell'attuale paradigma della coltivazione della vite, in cui la strategia nei vigneti non irrigati consiste nell'evitare la concorrenza con le colture di copertura attraverso applicazioni erbicide che accettano periodi imprevedibili di deficit o eccesso idrico.