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A three-dimensional numerical groundwater flow model to assess the feasibility of managed aquifer recharge in the Tamne River basin of Ghana | Entwicklung eines dreidimensionalen numerischen Grundwasserströmungsmodells zur Bewertung der Machbarkeit einer gesteuerten Grundwasserneubildung im Tamne River Basin in Ghana Un modèle d’écoulement souterrain en trois dimensions pour estimer la faisabilité de la recharge maitrisée des aquifères dans le bassin de la rivière Tamne au Ghana Un modelo numérico tridimensional de flujo de aguas subterráneas para evaluar la factibilidad de la recarga gestionada de acuíferos en la cuenca del río Tamne de Ghana 评估加纳 Tamne 河流域地下水回补可行性的三维数值地下水流模型 Um modelo numérico tridimensional de fluxo de água subterrânea para avaliar a viabilidade da recarga de aquífero gerenciada da na Bacia do Rio Tamne de Gana 全文
2022
Okofo, Louis Boansi | Martienssen, Marion
Increasing population growth and global climatic changes threaten water security in semiarid regions such as Northern Ghana. The Tamnean Plutonic Suite aquifer is the main source of water supply for the inhabitants of the Tamne River basin, which is a transboundary subbasin of the White Volta Basin, Ghana. The basin is a flood-prone area where flooding occurs every rainy season, but there is water scarcity during the dry season, mainly due to poor groundwater resources planning. It is expected that the population will increase in the next 10 years, implying a greater water demand. A steady-state and transient groundwater flow model has been developed to understand the hydrogeological conditions and assess the feasibility of managed aquifer recharge (MAR) in the area. A single granitic aquifer formation was delineated from the three-dimensional lithology modelling. The calibrated aquifer recharge through precipitation is very low due to high evapotranspiration and low rainfall. A MAR injection scenario was tested using the available treated floodwater that is registered during the rainy season in the area. The results show the total volume of water injected at the end of the 4-month study period is 11,000 m³/day (approximately 1.3 × 10⁶ m³), which significantly increases aquifer storage and groundwater levels. The volume of water recovered at the end of 8 months (1.4 × 10⁶ m³) is enough for domestic and irrigation purposes during the dry season. In general, MAR is feasible in augmenting the water levels in the area when combined with controllable irrigation and domestic withdrawals.
显示更多 [+] 显示较少 [-]Assessment of the level of activity of advective transport through fractures and faults in marine deposits by comparison between stable isotope compositions of fracture and pore waters | Évaluation du niveau d′activité du transport advectif à travers les fractures et les failles des dépôts marins en utilisant une comparaison entre les compositions en isotopes stables des eaux de fracture et celles des eaux interstitielles Evaluación del nivel de actividad del transporte advectivo a través de fracturas y fallas en depósitos marinos por comparación entre las composiciones de isótopos estables de las aguas de fractura y de poro 通过对比裂隙水和孔隙水稳定同位素成分评估海洋沉积物中裂隙和断层的对流传输水平 Avaliação do nível de atividade do transporte advectivo através de fraturas e falhas em depósitos marinhos pela comparação entre a composição de isótopos estáveis da água de fraturas e poros 全文
2022
Mochizuki, Akihito | Ishii, Eiichi
Assessment of the level of activity of advective transport through faults and fractures is essential for guiding the geological disposal of radioactive waste. In this study, the advective flow (active, inactive) of meteoric water through fractures is assessed by comparing stable isotopes (δD and δ¹⁸O) between fracture and pore waters obtained from four boreholes in marine deposits in the Horonobe area, Japan. At 27–83-m depth in one borehole and 28–250 m in another, the isotopic compositions of pore and fracture water reflect mixing with meteoric water, with stronger meteoric-water signatures being observed in the fracture water than in pore water of the rock matrix. At greater depths in these boreholes and at all sampling depths in the other two studied boreholes, the isotopic compositions of fracture and pore waters are comparable. These results suggest that the advective flow of meteoric water is active at shallow depths where fossil seawater is highly diluted in the two boreholes. This interpretation is compatible with the occurrence of present or paleo meteoric waters and tritium, whereby present meteoric water and tritium are limited to those depths in the two boreholes. This difference in the level of activity of advective flow is probably because of the glacial–interglacial difference in hydraulic gradients resulting from sea-level change. Although fractures are hydraulically connected to the surface through the sedimentary rock, advective flow through them is inferred to remain inactive so long as sea level does not fall substantially.
显示更多 [+] 显示较少 [-]Data-driven decision management of urban underground infrastructure through groundwater-level time-series cluster analysis: the case of Milan (Italy) | Gestion décisionnelle basée sur les données relatives aux infrastructures souterraines urbaines par l’analyse typologique des séries chronologiques des eaux souterraines: le cas de Milan (Italie) Manejo de decisiones basadas en datos de la infraestructura subterránea urbana a través del análisis de clústeres de series temporales de niveles de agua subterránea: el caso de Milán (Italia) 基于地下水位时间序列聚类分析的城市地下基础设施的数据驱动决策管理:以米兰(意大利)为例 Gestione data-driven a supporto delle decisioni per le infrastrutture sotterranee urbane attraverso la cluster analysis di serie storiche dei livelli piezometrici: il caso di Milano (Italia) Gerenciamento de decisão orientada por dados da infraestrutura subterrânea urbana por meio de análise de agrupamento de séries temporais de nível das águas subterrâneas: o caso de Milão (Itália) 全文
2022
Sartirana, Davide | Rotiroti, Marco | Bonomi, Tullia | De Amicis, Mattia | Nava, Veronica | Fumagalli, Letizia | Zanotti, Chiara
The significant increase in urbanization has resulted in greater use of the subsurface in urban planning and, therefore, increased interaction between groundwater and underground infrastructure. Numerical models are the primary tool adopted to manage the resulting problems; however, their construction is time- and cost-consuming. Groundwater-level time-series analysis can be a complementary method, as this data-driven approach does not require an extensive understanding of the geological and boundary conditions, even if providing insights into the hydrogeologic behaviour. Thus, a data-driven approach was adopted to analyse groundwater time-series of the shallow aquifer, occupied by several underground structures, beneath Milan city (Northern Italy). Statistical (Mann-Kendall and Sen’s slope estimator, autocorrelation and cross-correlation, hierarchical cluster analysis) and geospatial techniques were used to detect the potential variables influencing the groundwater levels of 95 monitoring wells, covering the period 2005–2019. A general rising trend of the water table was identified, with local hydrogeologic differences in the western and southernmost areas. Based on time-series analysis results, four management areas have been identified. These areas could act as future geographic units with specific groundwater management strategies. In particular, subsurface public car parks can be classified with respect to groundwater flooding as (1) not submerged, (2) possibly critical, or (3) submerged at different groundwater conditions. According to these outcomes, targeted guidelines for constructing new car parks have been elaborated for each management area. The methodology proved to be efficient in improving the urban conceptual model and helping stakeholders design the planned underground development, considering groundwater aspects.
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