In coral islands, groundwater is a crucial freshwater resource for terrestrial life, including human water supply. Response of the freshwater lens to expected climate changes and subsequent vegetation alterations is quantified for Grande Glorieuse, a low-lying coral island in the Western Indian Ocean. Distributed models of recharge, evapotranspiration and saltwater phytotoxicity are integrated into a variable-density groundwater model to simulate the evolution of groundwater salinity. Model results are assessed against field observations including groundwater and geophysical measurements. Simulations show the major control currently exerted by the vegetation with regards to the lens morphology and the high sensitivity of the lens to climate alterations, impacting both quantity and salinity. Long-term changes in mean sea level and climatic conditions (rainfall and evapotranspiration) are predicted to be responsible for an average increase in salinity approaching 140 % (+8 kg m⁻³) when combined. In low-lying areas with high vegetation density, these changes top +300 % (+10 kg m⁻³). However, due to salinity increase and its phytotoxicity, it is shown that a corollary drop in vegetation activity can buffer the alteration of fresh groundwater. This illustrates the importance of accounting for vegetation dynamics to study groundwater in coral islands.

The plain of Beijing city in China suffers severe land subsidence owing to groundwater overdraft. The maximum subsidence rate could reach 6 cm/year through the 2000s. An integrated subsidence-monitoring program was designed, including levelling survey, borehole extensometers and multilayer monitoring of groundwater level, with the aim to understand both hydrological and mechanical processes and to characterize the land subsidence. From multilayer compaction monitoring, the major compression layers were identified. The major strata contributing to compression deformation are the second (64.5–82.3 m) and third (102–117 m) aquitards, which contributed around 39 % of the total subsidence. Meanwhile, irrecoverable deformations were also observed in the second (82.3–102 m) and third (117–148 m) confined aquifers; they exhibit elasto-plastic mechanical behavior, which is attributed to the thin beds of silt or silty clay. Stress–strain analysis and oedometer tests were conducted to study the aquifer-system response to pumping　and to estimate the specific storage of the major hydrogeologic units. The results reveal the creep behavior and elasto-plastic, visco-elasto-plastic mechanical behavior of the aquitards at different depths. The compressibility of the aquitards in the inelastic range is about one order of magnitude larger than for the elastic range.

Water protection is one of the most important goals in environmental protection. The Clean Water Act in the USA and the Water Framework Directive (WFD) in Europe are the legal frameworks to facilitate the achievement of this goal. The question is raised of whether more information can be extracted from WFD-related groundwater data. To answer it, a methodology has been developed that is easy to use and could be implemented into official practice. A case study is presented in which the groundwater data of a sodic area in Austria (Seewinkel) is assessed. Eighteen parameters in groundwater sampled from 23 wells (1991–2011) were analyzed. With basic statistics, trend-, cluster-, Wilks’ λ and spatial sampling density analysis, local phosphorus and boron phenomena were described, along with the determining role of sulphate, groundwater flow, and the oxygen gradient in the area. As a final step, the spatial sampling density was determined. Regarding the current set of parameters, all the sampling sites are necessary and only in the case of certain parameters (Ca²⁺, Mg²⁺, K⁺, NO₃⁻, pH) could one sampling site be abandoned. The methodology applied brings a new perspective to exploring groundwater data collected according to the requirements of the WFD.

Groundwater discharge and non-point source (NPS) loading were evaluated along an urban reach of an eastern-slopes Rocky Mountains river (Bow River, Canada) to understand sources of water-quality impacts and baseflow. The discharge did not increase measurably over a 16-km reach. Groundwater in the river-connected alluvial aquifer was a mixture of river and prairie groundwater, with elevated chloride concentrations (average 379 mg L–¹) from road salt. Alluvial groundwater was the major NPS of chloride discharging to the river. Although the mass-flux based estimates of groundwater discharge were small (mean 0.02 m³s–¹km–¹, SD = 0.04 m³s–¹ km–¹, n = 30), the associated chloride mass flux over 16 km was significant (equivalent to that discharged from the city’s largest wastewater-treatment-plant effluent). Although local groundwater baseflow was previously thought to contribute significantly to overwinter baseflow in this reach, little contribution was measured in this study. Low baseflow generation is consistent with long-term river discharge data that show almost all of the baseflow generation occurs in the Rocky Mountain reach. Thus, local watershed areas are important for water-quality protection, but climate change in the headwaters is most salient to long-term flow.

The rapid population growth determines the appearance of vital needs such as mobilization of people to their places of study, work, entertainment and other activities such mobilization is performed in vehicles whose operation is slowly causing damage to the nature, on this aspect is developed in this research to be analyzed and then pose as a proposal to improve the octane of gasoline by adding hydrogen and oxygen by electrolysis of water, for reducing greenhouse gases and increasing combustion in an internal combustion engine of the vehicle fleet in the canton Latacunga, the work is divided in three sections; the first chapter is determined by the problematization and general concepts fundamental to the development of this research, in the second chapter contains methodological applications made for this job and the third chapter deals with the findings, conclusions and recommendations made to achieve the success of the investigation. | El vertiginoso crecimiento de la población determina el aparecimiento de necesidades vitales como la movilización de las personas a sus centros de estudio, trabajo, entretenimiento, y demás actividades; dicha movilización se la realiza en automotores cuyo funcionamiento, poco a poco está causando deterioro a la naturaleza, sobre este aspecto se desarrolla la presente investigación en la que se pretende analizar y posteriormente plantear como propuesta el mejoramiento del octanaje de la gasolina por la adición de hidrogeno y oxigeno mediante electrolisis del agua, para la disminución de los gases de efecto invernadero y el incremento de la combustión en un motor de combustión interna del parque automotor del cantón Latacunga, el trabajo se desarrolla en tres secciones, en el primer Capítulo está determinado por la problematización y conceptos generales, fundamentales para el desenvolvimiento de esta investigación, en el segundo Capítulo consta las aplicaciones metodológicas realizadas para este trabajo y en el Tercer Capítulo trata de los resultados, conclusiones y recomendaciones efectuadas para la consecución del éxito de la investigación

Irrigation in low-lying coastal plains may enhance the formation of fresh groundwater lenses, which counteract salinization of groundwater and soil. This study presents seasonal dynamics of such a freshwater lens and discusses its influence on the salinity distribution of the unconfined aquifer in the coastal plain of Ravenna, Italy, combining field observations with numerical modeling (SEAWAT). The lens originates from an irrigation ditch used as a water reservoir for spray irrigation. The geometry of the freshwater lens shows seasonal differences because of freshwater infiltration during the irrigation season and upconing of deeper saltwater for the remainder of the year. The extent of the freshwater lens is controlled by the presence of nearby drainage ditches. Irrigation also results in a temperature anomaly in the aquifer because of the infiltration of warm water during the irrigation season. The surficial zone in the vicinity of the irrigation ditch is increased considerably in thickness. Finally, different irrigation alternatives and the influence of sea-level rise are simulated. This shows that it is necessary to integrate irrigation planning into the water management strategy of the coastal zone to have maximum benefits for freshening of the aquifer and to make optimal use of the existing infrastructure.

La fortalesa dels Vilars es caracteritza per la seva fortificació complexa i defensa activa davant del risc de setge o bloqueig en el segle iv aC. El sistema inundable de fossats assegurava el proveïment i la gestió de l’aigua, reforçava la defensa i magnificava l’arquitectura del poder. El funcionament hidrològic del sistema fossat i pou cisterna de l’interior de la fortalesa no pot derivar-se de les condicions geomorfològiques i hidrològiques actuals, pels canvis en el relleu provocats pels anivellaments causats per la posada en reg fa més de cent anys, i, també, pel mateix regatge que ha modificat la dinàmica de la capa freàtica de la zona. Malgrat això, l’existència d’una capa freàtica artificial provocada pel reg permet estudiar la connexió entre les aigües d’escolament del torrent de l’Aixaragall —que suposadament alimentava el fossat— i les del pou cisterna. Mesures de conductivitat elèctrica de l’aigua en els diversos sistemes en tres moments corresponents a dues campanyes de reg (2012 i 2013) suggereixen una connexió entre la capa superficial de l’aqüitard format per les calcilutites oligocenes subjacents al fossat, les graves quaternàries que formen el con de dejecció del torrent de l’Aixaragall i el pou. En conseqüència, les mesures preses són compatibles amb l’alimentació del pou a partir del fossat inundat, i amb un origen superficial de l’aigua que devia omplir-lo procedent del torrent de l’Aixaragall.Paraules clau: arqueologia, hidrologia de pous, salinitat, fossat inundat, fortalesa dels Vilars. | The 4th c. BCE fortress of Els Vilars is marked by its complex fortification and its conception of active defence against the risk of siege or blockade. Its system of floodable moats assured its water supply and management, strengthened its defence and accentuated its architecture of power. The hydrological operation of the exterior moat-interior cistern well system could not be elucidated on the basis of today’s geomorphological and hydrological conditions because of the levelling of the surrounding topography since the advent of its irrigation over 100 years ago and because irrigation itself has changed the dynamics of the area’s water table. Despite this, the existence of an artificial water table produced by irrigation allows the study of the connection between the water runoff from the Aixaragall torrent, which supposedly fed the moat, and the water in the cistern well. Electrical conductivity measurements of the water in the various systems at three different moments in the course of two irrigation campaigns (2012 and 2013) suggest a connection between the surface layer of the aquitard formed by Oligocene calcilutites underlying the moat, the Quaternary gravels of the Aixaragall torrent’s alluvial fan and the cistern well. Consequently, the measurements recorded are consistent with the supply of the well from the flooded moat and with the supply of the moat by surface water from the Aixaragall torrent.Keywords: archaeology, well hydrology, salinity, flooded moat, fortress of Els Vilars. | La fortaleza de Els Vilars se caracteriza por su fortificación compleja y defensa activa frente al riesgo de asedio o bloqueo en el siglo iv aC. El sistema inundable de los fosos aseguraba el abastecimiento y la gestión del agua, reforzaba la defensa y magnificaba la arquitectura del poder. El funcionamiento hidrológico del sistema foso y pozo cisterna del interior de la fortaleza no puede derivarse de las condiciones geomorfológicas e hidrológicas actuales, debido a los cambios en el relieve provocados por nivelaciones causadas por la puesta en riego hace más de cien años, y al propio riego que ha modificado la dinámica de la capa freática de la zona. A pesar de ello, la existencia de una capa freática provocada por riego permite estudiar la conexión entre las aguas de escorrentía del torrente del Aixaragall —que supuestamente alimentaba el foso— y las del pozo cisterna. Medidas de conductividad eléctrica del agua en los diversos sistemas en tres momentos correspondientes a dos campañas de riego (2012 y 2013) sugieren una conexión entre la capa superficial del acuitardo formado por las calcilutitas oligocenas subyacentes en el foso, las gravas cuaternarias que forman el cono de deyección del torrente del Aixaragall y el pozo. En consecuencia, las medidas tomadas son compatibles con la alimentación del pozo a partir del foso inundado, y con un origen superficial del agua que debía llenarlo a partir del torrente del Aixaragall.Palabras clave: arqueología, hidrología de pozos, salinidad, foso inundado, fortaleza de Els Vilars.

The implementation of a geographic information system (GIS)/fuzzy spatial decision support system in the selection of sites for drinking-water pumping boreholes is described. Groundwater is the main source of domestic supply and irrigation in Korinthia prefecture, south-eastern Greece. Water demand has increased considerably over the last 30 years and is mainly met by groundwater abstracted via numerous wells and boreholes. The definition of the most “suitable” site for the drilling of new boreholes is a major issue in this area. A method of allocating suitable locations has been developed based on multicriteria analysis and fuzzy logic. Twelve parameters were finally involved in the model, prearranged into three categories: borehole yield, groundwater quality, and economic and technical constraints. GIS was used to create a classification map of the research area, based on the suitability of each point for the placement of new borehole fields. The coastal part of the study area is completely unsuitable, whereas high values of suitability are recorded in the south-western part. The study demonstrated that the method of multicriteria analysis in combination with fuzzy logic is a useful tool for selecting the best sites for new borehole drilling on a regional scale. The results could be used by local authorities and decision-makers for integrated groundwater resources management.