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991.
Tadashi Tanaka 《Hydrogeology Journal》2016,24(2):277-286
Many big earthquakes have occurred in the tectonic regions of the world, especially in Japan. Earthquakes often cause damage to crucial life services such as water, gas and electricity supply systems and even the sewage system in urban and rural areas. The most severe problem for people affected by earthquakes is access to water for their drinking/cooking and toilet flushing. Securing safe water for daily life in an earthquake emergency requires the establishment of countermeasures, especially in a mega city like Tokyo. This paper described some examples of groundwater use in earthquake emergencies, with reference to reports, books and newspapers published in Japan. The consensus is that groundwater, as a source of water, plays a major role in earthquake emergencies, especially where the accessibility of wells coincides with the emergency need. It is also important to introduce a registration system for citizen-owned and company wells that can form the basis of a cooperative during a disaster; such a registration system was implemented by many Japanese local governments after the Hanshin-Awaji Earthquake in 1995 and the Great East Japan Earthquake in 2011, and is one of the most effective countermeasures for groundwater use in an earthquake emergency. Emphasis is also placed the importance of establishing of a continuous monitoring system of groundwater conditions for both quantity and quality during non-emergency periods. 相似文献
992.
Anomalies found when apportioning responsibility for streamflow depletion are examined. The anomalies arise when responsibility is assigned to the two states that contribute to depletion of Beaver Creek in the Republican River Basin in the United States. The apportioning procedure for this basin presumes that the sum of streamflow depletions, computed by comparing simulation model runs with and without groundwater pumping from individual states, approximates the streamflow depletion when both states are pumping. In the case study presented here, this presumed superposition fails dramatically. The stream drying and aquifer-storage depletion, as represented in the simulation model used for allocation, are examined in detail to understand the hydrologic and numerical basis for the severe nonlinear response. Users of apportioning procedures that rely on superposition should be aware of the presence and likely magnitude of nonlinear responses in modeling tools. 相似文献
993.
Elad Dafny 《Hydrogeology Journal》2016,24(6):1329-1332
994.
Falk Händel Gaisheng Liu Johann Fank Franz Friedl Rudolf Liedl Peter Dietrich 《Hydrogeology Journal》2016,24(8):2079-2091
An approach to establish the recharge component of managed aquifer recharge (MAR) has recently been proposed that uses small-diameter shallow wells installed using relatively inexpensive drilling methods such as direct push. As part of further development of that approach, a generalized procedure is presented for a technical and economic assessment of the approach’s potential in comparison to other systems. Following this procedure, the use of small-diameter wells was evaluated both experimentally and numerically for a site located in southern Styria, Austria. MAR is currently done at the site using a horizontal pipe infiltration system, and system expansion has been proposed with a target rate of 12 l/s using small-diameter wells as one possible option. A short-duration single-well field recharge experiment (recharge rate 1.3–3.5 l/s) was performed (recharge by gravity only). Numerical modeling of the injection test was used to estimate hydraulic conductivity (K). Quasi-steady-state, single-well recharge simulations for different locations, as well as a long-term transient simulation, were performed using the K value calibrated from the field injection test. Results indicate that a recharge capacity of 4.1 l/s was achievable with a maximum head rise of 0.2 m at the injection well. Finally, simulations were performed for three different well fields (4, 6 and 8 wells, respectively) designed to infiltrate a target rate of 12 l/s. The experimental and numerical assessments, supported by a cost analysis of the small-diameter wells, indicate that the small-diameter wells are a viable, cost-effective recharge approach at this and other similar sites. 相似文献
995.
Juan Pérez Quezadas Victor M. Heilweil Alejandra Cortés Silva Luis Araguas María del Rocío Salas Ortega 《Hydrogeology Journal》2016,24(8):1953-1966
Geochemistry and environmental tracers were used to understand groundwater resources, recharge processes, and potential sources of contamination in the Rio Actopan Basin, Veracruz State, Mexico. Total dissolved solids are lower in wells and springs located in the basin uplands compared with those closer to the coast, likely associated with rock/water interaction. Geochemical results also indicate some saltwater intrusion near the coast and increased nitrate near urban centers. Stable isotopes show that precipitation is the source of recharge to the groundwater system. Interestingly, some high-elevation springs are more isotopically enriched than average annual precipitation at higher elevations, indicating preferential recharge during the drier but cooler winter months when evapotranspiration is reduced. In contrast, groundwater below 1,200 m elevation is more isotopically depleted than average precipitation, indicating recharge occurring at much higher elevation than the sampling site. Relatively cool recharge temperatures, derived from noble gas measurements at four sites (11–20 °C), also suggest higher elevation recharge. Environmental tracers indicate that groundwater residence time in the basin ranges from 12,000 years to modern. While this large range shows varying groundwater flowpaths and travel times, ages using different tracer methods (14C, 3H/3He, CFCs) were generally consistent. Comparing multiple tracers such as CFC-12 with CFC-113 indicates piston-flow to some discharge points, yet binary mixing of young and older groundwater at other points. In summary, groundwater within the Rio Actopan Basin watershed is relatively young (Holocene) and the majority of recharge occurs in the basin uplands and moves towards the coast. 相似文献
996.
Zhenjiao Jiang Gregoire Mariethoz Christoph Schrank Malcolm Cox Wendy Timms 《Hydrogeology Journal》2016,24(8):2143-2155
Coal-seam gas production requires groundwater extraction from coal-bearing formations to reduce the hydraulic pressure and improve gas recovery. In layered sedimentary basins, the coalbeds are often separated from freshwater aquifers by low-permeability aquitards. However, hydraulic connection between the coalbed and aquifers is possible due to the heterogeneity in the aquitard such as the existence of conductive faults or sandy channel deposits. For coal-seam gas extraction operations, it is desirable to identify areas in a basin where the probability of hydraulic connection between the coalbed and aquifers is low in order to avoid unnecessary loss of groundwater from aquifers and gas production problems. A connection indicator, the groundwater age indictor (GAI), is proposed, to quantify the degree of hydraulic connection. The spatial distribution of GAI can indicate the optimum positions for gas/water extraction in the coalbed. Depressurizing the coalbed at locations with a low GAI would result in little or no interaction with the aquifer when compared to the other positions. The concept of GAI is validated on synthetic cases and is then applied to the north Galilee Basin, Australia, to assess the degree of hydraulic connection between the Aramac Coal Measure and the water-bearing formations in the Great Artesian Basin, which are separated by an aquitard, the Betts Creek Beds. It is found that the GAI is higher in the western part of the basin, indicating a higher risk to depressurization of the coalbed in this region due to the strong hydraulic connection between the coalbed and the overlying aquifer. 相似文献
997.
Gas production from shale formations by hydraulic fracturing has raised concerns about the effects on the quality of fresh groundwater. The migration of injected fracking fluids towards the surface was investigated in the North German Basin, based on the known standard lithology. This included cases with natural preferential pathways such as permeable fault zones and fracture networks. Conservative assumptions were applied in the simulation of flow and mass transport triggered by a high pressure boundary of up to 50 MPa excess pressure. The results show no significant fluid migration for a case with undisturbed cap rocks and a maximum of 41 m vertical transport within a permeable fault zone during the pressurization. Open fractures, if present, strongly control the flow field and migration; here vertical transport of fracking fluids reaches up to 200 m during hydraulic fracturing simulation. Long-term transport of the injected water was simulated for 300 years. The fracking fluid rises vertically within the fault zone up to 485 m due to buoyancy. Progressively, it is transported horizontally into sandstone layers, following the natural groundwater flow direction. In the long-term, the injected fluids are diluted to minor concentrations. Despite the presence of permeable pathways, the injected fracking fluids in the reported model did not reach near-surface aquifers, either during the hydraulic fracturing or in the long term. Therefore, the probability of impacts on shallow groundwater by the rise of fracking fluids from a deep shale-gas formation through the geological underground to the surface is small. 相似文献
998.
Reza Ghasemizadeh Xue Yu Christoph Butscher Ingrid Y. Padilla Akram Alshawabkeh 《Hydrogeology Journal》2016,24(6):1463-1478
In northern Puerto Rico (USA), subsurface conduit networks with unknown characteristics, and surface features such as springs, rivers, lagoons and wetlands, drain the coastal karst aquifers. In this study, drain lines connecting sinkholes and springs are used to improve the developed regional model by simulating the drainage effects of conduit networks. Implemented in an equivalent porous media (EPM) approach, the model with drains is able to roughly reproduce the spring discharge hydrographs in response to rainfall. Hydraulic conductivities are found to be scale dependent and significantly increase with higher test radius, indicating scale dependency of the EPM approach. Similar to other karst regions in the world, hydraulic gradients are steeper where the transmissivity is lower approaching the coastline. This study enhances current understanding of the complex flow patterns in karst aquifers and suggests that using a drainage feature improves modeling results where available data on conduit characteristics are minimal. 相似文献
999.
Radon has been used to determine groundwater velocity and groundwater discharge into wetlands at the southern downstream boundary of the Crau aquifer, southeastern France. This aquifer constitutes an important high-quality freshwater resource exploited for agriculture, industry and human consumption. An increase in salinity occurs close to the sea, highlighting the need to investigate the water balance and groundwater behavior. Darcy velocity was estimated using radon activities in well waters according to the Hamada “single-well method” (involving comparison with radon in groundwater in the aquifer itself). Measurements done at three depths (7, 15 and 21 m) provided velocity ranging from a few mm/day to more than 20 cm/day, with highest velocities observed at the 15-m depth. Resulting hydraulic conductivities agree with the known geology. Waters showing high radon activity and high salinity were found near the presumed shoreline at 3,000 years BP, highlighting the presence of ancient saltwater. Radon activity has also been measured in canals, rivers and ponds, to trace groundwater discharges and evaluate water balance. A model of the radon spatial evolution explains the observed radon activities. Groundwater discharge to surface water is low in pond waters (4 % of total inputs) but significant in canals (55 l/m2/day). 相似文献
1000.
In (semi-)arid regions, available water resources are scarce and groundwater resources are often overused. Therefore, the option to increase available water resources by managed aquifer recharge (MAR) via infiltration of captured surface runoff was investigated for two basins in northern Jordan. This study evaluated the general suitability of catchments to generate sufficient runoff and tried to identify promising sites to harvest and infiltrate the runoff into the aquifer for later recovery. Large sets of available data were used to create regional thematic maps, which were then combined to constraint maps using Boolean logic and to create suitability maps using weighted linear combination. This approach might serve as a blueprint which could be adapted and applied to similar regions. The evaluation showed that non-committed source water availability is the most restricting factor for successful water harvesting in regions with <200 mm/a rainfall. Experiences with existing structures showed that sediment loads of runoff are high. Therefore, the effectiveness of any existing MAR scheme will decrease rapidly to the point where it results in an overall negative impact due to increased evaporation if maintenance is not undertaken. It is recommended to improve system operation and maintenance, as well as monitoring, in order to achieve a better and constant effectiveness of the infiltration activities. 相似文献