Injection of silicate grouting materials is widely used to create temporary horizontal layers for reducing inflow of groundwater at construction sites, in regions with shallow water tables. The erosion of a grouting layer was investigated by means of analytical solutions for groundwater flow and transport within a pit after construction finished. Erosion is assumed to occur by dissolution of the temporary injection layer and subsequent advective transport. Thereby, the hydraulic conductivity changes with time. This paper presents novel analytical solutions and approximate solutions for the major fluxes in the construction pit as a function of the domain settings, aquifer gradient and hydraulic conductivity. In addition, the mass flux and the dilution ratio of erosion-related components leaving the construction pit and entering the aquifer are quantified. Derived solutions are verified against numerical simulations. A sensitivity study shows the impact of domain settings on fluxes and dilution ratio. The results confirm that mass flux of grout components increases with ongoing erosion. Thus, its effect on groundwater quality increases with time after construction ceased.

Construction of a conveyance tunnel through rock often induces the ingress of groundwater into the tunnel, a flow that changes both the hydrogeological regime of the tunnel and its environment. To explore this key interaction, a novel modeling approach using the conduit flow process (CFP) is developed that considers both the hydraulic head and the ingress of water from the rock matrix during excavation. The resulting flow values are predicted through an adapted MODFLOW numerical model into which the tunnel is introduced with the aid of the new CFP approach. The CFP approach can simulate both laminar and turbulent flow in the tunnel whether the flow is free surface or pressurized. Several simulations, including one for which the permeability of the tunnel perimeter is assumed to be identical to the hydraulic conductivity of the surrounding rock matrix, are then used to explore the sensitivity of the predicted head and flow conditions to the permeability of the tunnel perimeter. Comparisons of the numerical results with field data from the Kerman Water Conveyance Tunnel in Iran show that the proposed approach accurately predicts the spatial variation of both groundwater ingress and hydraulic head.

The Ica area of south-eastern Peru has evolved rapidly since the late 1990s into the most advanced agricultural development in the country. The intensive use of waterwells for year-round irrigation, primarily of asparagus, is the basis for an export industry worth about US$ 6,000 M/a, but one which is threatened by serious groundwater sustainability concerns. The public water-resource administration and private agricultural developers are beginning to confront the problem, which has already had a significant social cost, through developing measures to improve the groundwater balance whilst assuring agricultural production. This report presents the long-term evolution of land management and groundwater use in the area, and considers the feasibility of applying an adaptive and integrated water resources management (IWRM) approach to the system, with particular attention to managed aquifer recharge techniques.

This research seeks to identify groundwater recharge and discharge areas in the administrative aquifers of the Ayuquila-Armeria river basin in the states of Jalisco and Colima, Mexico. The Ayuquila-Armeria river basin is one of the 15 most important of the 100 rivers running across the Pacific slope, and is among the 43 most important rivers at the country level. The regional climate is warm-humid in lowlands and subhumid temperate in highlands, with a summer rainy season (June to October) and a dry season the rest of the year. The basin shows a striking relief: from sea level to 4260 m a.s.l. at Nevado de Colima. The identification of these areas was based on a multi-criteria analysis of surface indicators of recharge and discharge areas supported by the flow systems theory (FST). This allows a systemic view of the environment, integrating various elements of nature, in addition to acknowledging groundwater and geological agent that causes a wide variety of processes and manifestations on the surface. The integration of Geographic Information Systems (GIS) and the Multi-Criteria Analysis (MCA) made possible to evaluate the potential recharge/ discharge at the regional level by analyzing physical variables such as lithology, soil, relief, slope, vegetation, precipitation, and a topographic humidity index. In the study area, the territory with high recharge potential ranges from 21% to 80%; the area with low and very low recharge potential, from 4% to 30%. The main potential recharge areas are located in the upper portion of mid-elevation and low mountains covered by pine-oak, oak, and tropical deciduous forests, and grasslands, and to a lesser extent, fir and mountain cloud forests. Soil types include mainly Regosol, Leptosol, Cambisol, Luvisol, Andosol, Umbrisol, and Phaeozem in slopes of 15%-30% covering units of rhyolitic tuff, andesite-basalt, andesite, lahar-pyroclastic rock, granite-granite diorite, and limestone. These areas are located mainly in Sierra de Cacoma-Manantl, Sierra Verde, Sierra de Quila, Sierra de Tapalpa, and the Nevado de Colima volcanic complex. For its part, discharge areas are found mainly in the coastal plains of Jalisco and Colima, associated with Calcisol, Arenosol, Fluvisol, Planosol, Gleysol, Solonchak, and Vertisol soils, and with with halophytic-hydrophytic grassland, bulrush, and mangrove vegetation. These are located in inland-lake areas in San Marcos, Sayula, and Zapotlán. Other discharge areas are the plains and intermontane valleys of Union de Tula and Autlán-El Grullo, as well as the bottom of V-valleys in certain areas of the basin. These can act as natural hydraulic boundaries of flow systems, limiting the amount of groundwater in each zone. The lateral alternation of recharge and discharge areas implies that the water recharged in a particular region may flow to a number of discharge areas, i.e., the water discharged in a given region may come from different regions. The above has important implications in the estimation of the availability estimated from the water balance, since groundwater may flow to more than one discharge area within the same “administrative” aquifer. This type of studies are a first approach providing innovative evidence to the systemic study of groundwater, i.e., the recharge-discharge areas. Their application positively supplements the results of the water balance used in the official evaluation of groundwater availability in Mexico. | Esta investigación busca identificar las zonas de recarga y descarga del agua subterránea en la cuenca del río Ayuquila-Armería en los estados de Jalisco y Colima. La identificación de estas zonas se logró mediante un análisis multicriterio con la teoría de los sistemas de flujo (TSF). Esta teoría permite obtener una visión sistémica del ambiente, integrando diversos elementos de la naturaleza, además de reconocer el agua subterránea como agente geológico causante de una gran variedad de procesos y manifestaciones en la superficie a través de condiciones naturales contrastantes entre la zona de recarga y descarga de agua subterránea. La integración de los Sistemas de Información Geográfica (SIG) y el Análisis Multicriterio (AMC) permitió identificar los sitios con mayor potencial de recarga y descarga analizando geología, suelo, topoformas, pendiente, vegetación e índice topográfico de humedad (ITH). La superficie con alto potencial de recarga varía de 21% a 80%, mientras que la superficie de descarga, de 4% a 30%. Las principales zonas potenciales de recarga son la sierra de Cacoma-Manantlán, la sierra Verde, la sierra de Quila, la sierra de Tapalpa y el complejo volcánico del Nevado de Colima. Por su parte, las zonas de descarga se encuentran principalmente en las planicies costeras de Jalisco y Colima, así como en una zona de lagos interiores en San Marcos, Sayula y Zapotlán. Otras zonas de descarga las constituyen las planicies y los valles intermontanos de Unión de Tula y Autlán-El Grullo, así como los fondos de valles en V en determinadas zonas de la cuenca.

This study improves knowledge on the hydrogeology of Ischia Island, an active volcano of southern Italy. Combining previous published and unpublished data with newly collected data, and through the results of simplified numerical models, the existing conceptual hydrogeological model of the volcanic island has been reviewed and the present impact of intensive withdrawals on the island’s groundwater resources has been examined. Two areas with different hydrogeological characteristics have been recognized: (1) the resurgent block of Mt. Epomeo, where an independent and uplifted basal groundwater circulation exists; (2) the external areas of Mt. Epomeo, where a continuous basal aquifer and local discontinuous perched aquifers have been distinguished. The marginal faults of the resurgent block of Mt. Epomeo represent the preferential pathways of ascending deep fluids. In natural conditions, the island’s aquifers are recharged by rainfall and by deep fluids from beneath, discharging towards the sea and the springs. Since the start of activity at the spa facilities, involving intensive pumping from wells, a further and significant recharge of the aquifers has come from seawater and from increased upwelling of the deep fluids. Although this does not compromise the sustainability of the groundwater withdrawals in quantitative terms, the pumping rates determine the quality of the water captured by the wells. The great variability in temperature and chemical composition of groundwater of the island is also influenced by local hydrogeological parameters and characteristics of the wells from which the water samples were taken, as well as the phenomena of interaction among different end-members.

Effective management of groundwater resources requires an understanding of the complexity of groundwater systems by the experts, and a certain level of understanding and trust in management by the community. Groundwater data sharing and visualisation systems are being used across the world to provide an insight into groundwater systems. The 3D Water Atlas of the Surat Basin, Queensland, Australia, provides a way of visualising and analysing hydrogeochemical information in a way that is accessible to a wide audience. It combines data on the location, construction, water chemistry and water levels of groundwater bores within the framework of a geological model and other spatial datasets. It is freely available on a single Web-based interactive three-dimensional (3D) platform. Visualisation tools such as line graphs of groundwater bore water levels, pie charts and animations of major ions, can be used to advance understanding of groundwater resources. For example, a general regional decline, but with local variability in Hutton Sandstone groundwater levels in the Surat Basin can be seen by using the 3D Water Atlas. The combination of groundwater data with filtering, analysis and visualisation tools in the 3D Water Atlas helps to communicate complex hydrogeological concepts. It can also assist with the management of groundwater resources by improving confidence in decision-making, as necessary information can be viewed together, in context. Although the 3D Water Atlas was produced for the Surat Basin, its design means that 3D Water Atlases for different regions can be produced easily.

Fil: Lanzaro, María Verónica. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas; Argentina. | En las últimas décadas, el crecimiento urbano ha provocado un impacto significativo en el ambiente. En ocasiones, la ausencia o aplicación inadecuada de planes de ordenamiento urbano ha generado patrones irracionales de uso del suelo caracterizados por una alta concentración en las áreas centrales, en contraposición con una ocupación desordenada en las periferias urbanas con ausencia de regulación normativa. Ambas situaciones acrecientan la degradación ambiental. El aprovechamiento del espacio subterráneo se ha convertido en una alternativa para ciudades con problemas de crecimiento y densidad poblacional, aunque generalmente, no se comprende la compleja interacción entre el uso del suelo y el comportamiento del sistema hídrico subterráneo ni se aborda considerando aspectos normativos. La ciudad de Santa Fe no está exenta de estas situaciones. El objetivo de esta tesis es evaluar la relación entre las construcciones subterráneas existentes y las características del sistema acuífero que subyace a la ciudad de Santa Fe, Argentina, a fin de formular lineamientos técnicos y normativos que optimicen los proyectos de obras subterráneas. Para ello se analizaron las variaciones espaciales y temporales de niveles freáticos para un período de 10 años, la calidad química del agua subterránea, y los diversos usos actuales del suelo con aprovechamiento subterráneo. Los resultados obtenidos contribuirán a la seguridad, funcionalidad y racionalidad económica de futuras obras subterráneas y a la generación de una conciencia de gestión integral que asuma la relación compleja entre el uso del suelo urbano y el medio hidrogeológico en la toma de decisiones y planificación de la ciudad. | In recent decades, urban growth has caused a significant impact on the environment. Occasionally, the absence or improper application of urban planning plans has generated irrational land use patterns characterized by highly concentration in central areas, as opposed to a disorderly occupation in urban peripheries with the absence of urban regulation. Both situations increase environmental degradation. The use of underground space has become an alternative for cities with problems of growth and population density, although the complex interaction between land use and the behavior of the groundwater system is not generally understood, nor is it addressed considering regulatory aspects. The city of Santa Fe is not exempt from these situations. The objective of this thesis work is to evaluate the relationship between existing underground constructions and the characteristics of the aquifer system that underlies the city of Santa Fe, Argentina, in order to formulate technical and normative guidelines to optimize underground works projects. To this end, the spatial and temporal variations in groundwater levels for a period of 10 years, the chemical quality of the groundwater, and the various current land uses with underground use were analyzed. The results obtained will contribute to the safety, functionality and economic rationality of the projects of future underground works and to the generation of an integral management awareness that assumes the complex relationship between urban land use and the hydrogeological environment in decision-making and city planning.

En este trabajo se realizó la valoración de las amenazas naturales, antrópicas y socio-naturales, así como también la vulnerabilidad a las que se encuentran expuestas las Plantas de Tratamiento de Agua Potable Subterránea (PTAP) de los barrios La Reliquia, Pinares de Oriente y 13 de Mayo, ubicadas en la ciudad de Villavicencio, Meta, mediante la metodología Delphi y el método planteado en la Herramienta Metodológica para la Formulación de Programas de Gestión del Riesgo de Desastres en los Servicios de Acueducto, Alcantarillado y Aseo (Ministerio de vivienda, ciudad y territorio, 2014), con el fin de conocer el riesgo presente y la gravedad del mismo, para así poder contribuir al cumplimiento por parte de la Empresa de Acueducto y Alcantarillado de Villavicencio (EAAV) de la resolución 0549 de 2017 expedida por el ministerio de Salud y Protección Social y del Ministerio de Vivienda, Ciudad y Territorio donde se da una guía técnica para la elaboración del estudio del conocimiento del riesgo que deben cumplir los servicios públicos, como el servicio de acueducto. El método Delphi se desarrolló mediante un cuestionario realizado a cinco (5) trabajadores del área de planeación de la EAAV, en la cual se realizaron preguntas acerca de las amenazas y la vulnerabilidad a los que se encuentra expuesto el sistema de potabilización de agua, para conocer los riesgos más relevantes de cada una de las PTAP y así poder diseñar en el futuro el plan de riesgo por parte de la empresa y hacer planes para la disminución del riesgo en cada planta, para la identificación de los riesgos se tuvo en cuenta las matrices y el formato del conocimiento de riesgo descrito en la herramienta metodológica de la Unidad Nacional de Gestión del Riesgo (UNGR). Lo anterior, se realizó con el ánimo de que los resultados brinden un panorama de la situación actual o que se pueda presentar a futuro en las PTAP estudiadas con respecto a los riesgos evaluados, en los resultados se evidencia que los resultados son similares en varios tipos de riesgo como los naturales y socio-naturales, en cuanto a los riesgos antrópicos, estos difieren de una manera notable entre cada una de las plantas. Según el estudio realizado, la amenaza más alta que afecta a las tres plantas de tratamiento del estudio es el riesgo sísmico, seguido de las acciones violentas, debido el tipo de población que se maneja y a la ubicación geográfica del municipio de Villavicencio en el cual se encuentran ubicadas las PTAP de origen subterráneo. | In this work, the assessment of the natural, anthropic and socio-natural risks to which the Underground Drinking Water Treatment Plants (PTAP) of La Reliquia, Pinares de Oriente and 13 de Mayo neighborhoods, located in the city of Villavicencio, Meta, using the Delphi methodology and the method proposed in the Methodological Tool for the Formulation of Disaster Risk Management Programs in the Aqueduct, Sewerage and Sanitation Services (Ministry of Housing, City and Territory, 2014) , in order to know the present risk and its severity, in order to be able to contribute to compliance by the Villavicencio Aqueduct and Sewer Company (EAAV) of resolution 0549 of 2017 issued by the Ministry of Health and Social Protection and of the Ministry of Housing, City and Territory where a technical guide is given for the elaboration of the study of the risk knowledge that must be fulfilled. r public services, such as the aqueduct service. The Delphi method was developed through a questionnaire made to five (5) workers in the planning area of the EAAV, in which questions were asked about the threats and vulnerability to which the water purification system is exposed, for know the most relevant risks of each one of the PTAPs and thus be able to design in the future the risk plan by the company and make plans for the reduction of the risk in each plant, for the identification of the risks took into account the matrices and the risk knowledge format described in the methodological tool of the National Unit of Risk Management (UNGR). This was done with the aim that the results provide an overview of the current situation or that may be presented in the PTAP studied in the future with respect to the risks evaluated. The results show that the results are similar in several types risk as natural and socio-natural, in terms of anthropogenic risks, these differ in a remarkable way between each of the plants. According to the study carried out, the highest risk affecting the three treatment plants of the study is the seismic risk, followed by the violent actions, due to the type of population that is managed and the geographic location of the municipality of Villavicencio, in which located PTAPs of underground origin. | Ingeniero Ambiental | http://www.ustavillavicencio.edu.co/home/index.php/unidades/extension-y-proyeccion/investigacion | Pregrado

Permafrost in Arctic watersheds limits soil biological activity to a thin, seasonally thawed active layer that contributes water to streams. In many hillslopes, relatively wet drainage features called water tracks have distinct freeze-thaw patterns that affect groundwater flow and storage, and thus the export of heat and solutes to Arctic streams. This study uses groundwater flow and energy transport models to examine potential controls on the timing and duration of freeze–thaw conditions and the magnitude of temperature fluctuations within water tracks and their adjacent hillslopes. The simulated length of the active-layer thaw season varies by 1 month over the range of snow-cover and mean annual air-temperature scenarios simulated. The timing and duration of freezing is particularly sensitive to depth and duration of snow cover. Thus, the deeper snowpack covers that can accumulate in water tracks contribute to their more persistent thaw conditions and their ability to conduct groundwater downslope. A three-dimensional simulation shows that during the summer thaw season, the water track captures groundwater laterally from half way across the hillslope. The models presented here elucidate key mechanisms driving small-scale variation in the active-layer thermal regime of tundra hillslopes, which may be responsible for changes in drainage-network geometry and Arctic biogeochemical fluxes under a warming climate.

Stable isotopic composition (δ²H, δ¹⁸O) of river water, groundwater, and paddy water in the Mun River catchment, northeast Thailand, were determined to investigate the hydrological processes and the impacts of natural and anthropogenic activities on the water cycle. Quantities of δ²H (−93.9 to −25.4‰) and δ¹⁸O (−12.24 to −2.22‰) in river water in the wet season follow the trend: upper reaches > middle reaches ≈ lower reaches. Trends for δ²H (−52.3 to −22.0‰) and δ¹⁸O (−6.37 to −1.36‰) in the dry season are: upper reaches ≈ middle reaches > lower reaches. In the dry season, groundwater (δ²H: −57.5 to −34.6‰, δ¹⁸O: −8.24 to −4.40‰) shows a lighter isotopic composition, and paddy water (δ²H: −18.2‰, δ¹⁸O: −0.72‰) shows the highest isotopic composition. Spatial variation of δ¹⁸O and deuterium excess suggests that groundwater exchanges with surface water frequently. Rainfall and river water recharge groundwater in the wet season, and groundwater flows back to the river in the dry season, especially in the middle reaches. This process is most likely related to impoundment of the rivers by large dams. On the other hand, the lowest values of stable isotopes of river water are coincident with the extreme flooding that was produced by Tropical Storm Sonca in July 2017. This study contributes to a better understanding of hydrological processes in the Mun River catchment and provides a perspective on the application of stable isotopes to other large tropical monsoon catchments around the world.