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Konstantinos Chalikakis Valérie Plagnes Roger Guerin Rémi Valois Frank P. Bosch 《Hydrogeology Journal》2011,19(6):1169-1180
The karst environment is one of the most challenging in terms of groundwater, engineering and environmental issues. Geophysical methods can provide useful subsurface information in karst regions concerning, for instance, hazard estimation or groundwater exploration and vulnerability assessment. However, a karst area remains a very difficult environment for any geophysical exploration; selection of the best-suited geophysical method is not always straightforward, due to the highly variable and unpredictable target characteristics. The state of the art is presented, in terms of the contributions made by geophysical methods to karst-system exploration, based on extensive analysis of the published scientific results. This report is an overview and should be used as a preliminary methodological approach, rather than a guideline. 相似文献
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Rémi Valois Christian Camerlynck Amine Dhemaied Roger Guerin Gaghik Hovhannissian Valérie Plagnes Faycal Rejiba Henri Robain 《地球表面变化过程与地形》2011,36(9):1183-1192
In the protection of karstic aquifers, the role played by dolines is of interest as these shallow structures can be preferential infiltration pathways for groundwater recharge. In this study, three depressions in South France (Orniac, Lot) were identified and characterized using combined geophysical methods. Apparent conductivity mapping allows precise definition of dolines corresponding to topographic depressions. It also reveals other dolines that are hidden by soil cover. Electrical resistivity and seismic refraction tomography provide detailed cross‐sections. Even though the dolines studied are close one to another, they exhibit great variability in shape and content. Moreover, time‐lapse data show that the most saturated regions are on the edges of the first doline. Such information helps to evaluate human impacts and forecast potential groundwater contamination. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Amanda E. Valois Juliet R. Milne Mark W. Heath Rob J. Davies-Colley Emily Martin Rebecca Stott 《新西兰海洋与淡水研究杂志》2020,54(2):200-217
ABSTRACT Water is an important component of many recreational opportunities and New Zealand invests significant resources in recreational water quality (RWQ) monitoring to assess risks to public health. However, monitoring primarily focuses on microbiological hazards and RWQ is considerably broader than this. The goal of this study was to take a comprehensive approach to evaluating RWQ while exploring the potential for greater public involvement in monitoring. A popular river swimming site was co-monitored weekly by volunteers and a council field officer. The attributes monitored–water temperature, visual clarity, benthic cyanobacteria and filamentous periphyton cover, E. coli and rubbish–were identified from a volunteer workshop. There was good concordance between volunteer and council data suggesting that volunteer measurements can be considered reliable. This highlights the potential for volunteers, with professional support, including training and quality assurance, to extend council RWQ surveillance to additional monitoring sites while improving public engagement on water management. 相似文献
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Remi Valois Shelley MacDonell Jorge Humberto Núñez Cobo Héctor Maureira-Cortés 《水文科学杂志》2020,65(4):597-609
ABSTRACTGroundwater is an important resource in semi-arid Chile to meet local social, economic and environmental water demands. Historical ground water level (GWL) data (1986–2014) in the Coquimbo Region were analysed to characterize short and long-term alluvial aquifer dynamics. Long-term trends were assessed using a seasonal Mann-Kendall trend test, which indicated that more than 80% of the time series exhibit a negative trend. Short-term analysis using cross-correlation provided information on recharge origin and its spatial pattern. Runoff and GWL are highly correlated depending on elevation, signifying that stream to aquifer flow is an important recharge process at higher altitudes. Long-term recharge behaviour was characterized using time-frequency wavelet power spectra. The results show significant amplitude of the 5-year recharge period for GWL, which is driven by a 5-year El Niño index periodicity. Such results provide key information of the spatiotemporal functioning of aquifers. 相似文献
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Roger Guérin Jean-Michel Baltassat Marie Boucher Konstantinos Chalikakis Pierre-Yves Galibert Jean-François Girard Valérie Plagnes Rémi Valois 《Comptes Rendus Geoscience》2009,341(10-11):810-817
In the framework of the management of karstic aquifers, geophysical reconnaissance can be used to locate conduits and caves, and to characterise the surrounding limestone matrix. Suitable characterisation of heterogeneities in the karstic environment is, however, challenging for ground-based geophysical methods. The present article describes the results, and evaluates the response and accuracy of combined geophysical measurements carried out at the Poumeyssen test site in France, involving electrical resistivity imaging (ERI), magnetic resonance sounding (MRS), “mise-à-la-masse” electrical mapping, and seismic tomography. This site provides the opportunity to study a relatively wide, shallow, water-filled conduit whose location and shape are known from topographic work carried out by cave divers. Seismic and MRS provided the exact location and width of the conduit, to within a few meters. The seismic and electrical data suggest that the limestone medium surrounding the conduit is not homogeneous. 相似文献
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Assessment of water resources to support the development of irrigation in northwest Cambodia: a water budget approach 总被引:2,自引:2,他引:0
Water availability is the primary constraint on the improvement of food security in rural areas in northwestern Cambodia. A 4-year study was carried out in the upper Stung Sreng watershed to assess water resources. Four sub-watersheds with different land cover types, ranging in size from 1.5 to 185 km2, were monitored using dedicated weather stations and rain- and streamgauges. Geophysics and observation boreholes were used to characterize aquifers. Rainwater is mostly split into evapotranspiration (annual mean of 54% rainfall) and streamflow components (49%), because groundwater recharge is low (1%). Thus, rainwater and streamflow are the main sources for irrigation development. Groundwater can be used only in specific locations for low water-demand crops. A total of 186 household ponds and three village-scale dams were built and 31 wells were installed. The household pond was determined to be the best solution for irrigation development because of its simple management.
EDITOR A. Castellarin ASSOCIATE EDITOR M. Piniewski 相似文献
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Jean Michel Vouillamoz Rémi Valois Sambo Lun Delphine Caron Ludovic Arnout 《Hydrogeology Journal》2016,24(1):195-209
Since the end of the Cambodian Civil War in 1998, the population of the Oddar Meanchey province has drastically increased despite the lack of adequate infrastructure, including basic amenities such as drinking-water supply. To improve the access to drinking water, governmental and aid agencies have focussed on drilling shallow boreholes. The use of groundwater for irrigation is also a growing concern to cope with the occasional late arrival of the rainy season or to produce food during the dry season. Since the groundwater resource in the province has not been documented, a 4-year study was undertaken (2011–2014), aiming to estimate the capability of groundwater to supply domestic needs and supplementary irrigation for rice production. Aquifer properties were estimated by combined use of hydrogeological techniques with the geophysical magnetic resonance sounding method. Groundwater storage and recharge were estimated based on new developments in the application of the geophysical method for quantifying specific yield. The median groundwater storage of the targeted sandstone aquifer is 173 mm, the recharge is diffuse and annually ranges from 10 to 70 mm, and the transmissivity is low to medium. Simulations of pumping indicate that the aquifer can easily supply 100 L of drinking water per capita daily, even considering the estimated population in 2030. However, the shallow aquifer can generally not deliver enough water to irrigate paddy fields of several hectares during a 2-month delay in the onset of the monsoon. 相似文献