Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title><jats:p>The causes of land subsidence in Kawajima, Japan, have been investigated through data compilation and numerical modeling. Land subsidence has progressed despite a gradual increase in the hydraulic head in the long term. Taking into account the temporal changes and depth distribution of groundwater abstractions, the contraction of formations, and the complexity of the hydrogeological structures, it is proposed that agricultural groundwater use is one of the main triggers for land subsidence. A one-dimensional numerical simulator for coupled groundwater flow and soil deformation was developed with an evolutionary algorithm for model calibration. The calculated spatiotemporal changes in the past-maximum effective stress showed that plastic consolidation in the clayey layers progressed part by part every summer season resulting in long-term and gradual land subsidence under the same range of groundwater level fluctuations. The results also showed that the plastic deformation occurred in both the Holocene and Pleistocene sediments in the drought years, leading to significant subsidence. The model’s predictive performance showed good potential except for a structural prediction error after the Tohoku Earthquake in 2011. The scenario analysis indicated that management of the groundwater level in summer is one of the effective countermeasures in suppressing land subsidence caused by seasonal groundwater level fluctuations. These methodologies and findings can be used for groundwater management in similar cases around the world. Additional investigation is necessary on the influence of large earthquakes in deformation conditions in order to further improve the developed model.</jats:p>

<jats:title>Abstract</jats:title><jats:p>For an increasing number of urban areas in Denmark and other countries with a temperate climate, large seasonal variations in precipitation, evaporation, and groundwater recharge cause problems with high groundwater levels during winter for private house owners, industry, public institutions, and infrastructure. Several factors contribute to the problem, e.g., an increase in winter precipitation, renovation of old leaky sewer pipes (previously acting as drain systems), and closure of groundwater abstraction for drinking water in urban areas in response to pollution. Four adaptation measures are compared with a detailed hydrological model for the town of Sunds, located in the western part of Denmark. Two ‘grey’, one ‘green’ and one ‘blue’ measure are evaluated. The grey solutions involve (1) installing drainage pipes (a third pipe) alongside the existing sewer pipes, and (2) lowering the water table by groundwater pumping from shallow wells, including storage of water in deeper aquifers for use in the drier summer; the green solution involves planting new forest in and around the town; and the blue solution is to establish a new ditch in the town. A climate model that projects more precipitation, especially in the winter, is used to evaluate the robustness of the different measures in a wetter climate for the northern European area. The hydrological modelling shows that the third pipe is the most effective climate-change adaptation of the four measures tested. The new ditch is an effective solution to lower the water table but with a more limited areal coverage.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Hydrogeologic systems in the southern Cascade Range in California (USA) develop in volcanic rocks where morphology, stratigraphy, extensional structures, and attendant basin geometry play a central role in groundwater flow paths, groundwater/surface-water interactions, and spring discharge locations. High-volume springs (greater than 3 m<jats:sup>3</jats:sup>/s) flow from basin-filling (&lt;800 ka) volcanic rocks in the Hat Creek and Fall River tributaries and contribute approximately half of the average annual flow of the Pit River, the largest tributary to Shasta Lake. A hydrogeologic conceptual framework is constructed for the Hat Creek basin combining new geologic mapping, water-well lithologic logs, a database of active faults, LiDAR mapping of faults and volcanic landforms, streamflow measurements and airborne thermal infrared remote sensing of stream temperature. These data are used to integrate the geologic structure and the volcanic and volcaniclastic stratigraphy to create a three-dimensional interpretation of the hydrogeology in the basin. Two large streamflow gains from focused groundwater discharge near Big Spring and north of Sugarloaf Peak result from geologic barriers that restrict lateral groundwater flow and force water into Hat Creek. The inferred groundwater-flow barriers divide the aquifer system into at least three leaky compartments. The two downstream compartments lose streamflow in the upstream reaches (immediately downstream of the groundwater-flow barriers) and gain in downstream reaches with the greatest inflows immediately upstream of the barriers.</jats:p>

<jats:title>Abstract</jats:title><jats:p>Consideration of regional groundwater flow in aquifer systems allows for solving groundwater issues on a larger scale than single aquifers and contributes to all practical aspects of the UN’s Sustainable Development Goals for water. The approach has been extended to a wide range of hydrogeological environments. However, it suffers from poorly constrained terminology and conceptualisation, compounded by the difficulties of interpreting complex groundwater flow systems. This essay aims to initiate a discussion on improving the application of regional groundwater flow approaches.</jats:p>