The hydrogeology and hydrogeochemistry of the Barwon Downs Graben aquifer, southwestern Victoria, Australia

The Barwon Downs Graben lies on the northern flanks of the Otway Ranges and is situated approximately 70 km southwest of Geelong, Victoria, Australia. The major lower Tertiary Barwon Downs Graben aquifer comprises highly permeable sands and gravels interbedded with clays and silts of the hydraulically interconnected Pebble Point, Dilwyn and Mepunga Formations. Groundwater flows east into the Barwon Downs Graben from the Barongarook High, and yields ¹⁴C ages up to ～20 ka implying that recharge rates are low and, consequently, that the resource could be impacted by overabstraction. The presence of three different lithological units has led to the development of localized flow systems that has resulted in a lack of regular spatial variations in groundwater chemistry. Stable isotopic data suggests that groundwater was recharged under similar climatic conditions as of today. The major ion chemistry of the freshest groundwater is dominated by Na and HCO₃ while higher TDS groundwater, from the confining Narrawaturk Marl, is dominated by Na and Cl. Cl/Br ratios are close to rainfall suggesting that halite dissolution is not the principle source of salts. An excess of Na relative to Cl in fresher groundwater suggests that feldspar dissolution has occurred, however, water–rock interaction is limited. The concentrations of Ca, Mg, and SO₄ are controlled by silicate dissolution and ion-exchange reactions with clays.     

The Nubian Aquifer in Southwest Egypt

Synthetic Aperture Radar (SAR) images, and topographic and groundwater data are used to understand heterogeneities of the Nubian Aquifer between 20–24.5°N and 25–32°E in southwest Egypt. New fluvial and structural interpretations emphasize that the desert landscape was produced by fluvial action, including newly mapped alluvial fans. In central locations, braided channels are spatially aligned with a NE structural trend, suggesting preferential water flow paths that are consistent with the local direction of groundwater flow. The alluvial fans and structurally enclosed channels coincide with gentle slopes and optimal recharge conditions (1–5%) derived from the new Shuttle Radar Topographic Mission (SRTM) slope map, indicating that these areas have high groundwater potential. The SAR interpretations are correlated with anomalies observed in groundwater data from 383 wells. Results suggest a relationship between the spatial organization of fluvial and structural features and the occurrence of low-salinity groundwater. Low-salinity water exists adjacent to the alluvial fans and in SW reaches of the structurally enclosed channels. Wells in the vicinity of structures contain low-salinity water, emphasizing that knowledge of structural features is essential to understand groundwater flow paths. The new approach is cost effective and noninvasive and can be applied throughout the eastern Sahara to assist in resource management decisions and support the much needed agricultural expansion.     

广东石人樟钨矿矿山采矿塌陷区提取及成果应用

地裂缝、塌陷坑是塌陷区的两个重要要素,根据两期Spot6遥感影像判读解译,对地下开采矿山塌陷区进行遥感监测,圈定两期影像矿山采矿造成的采矿塌陷坑、地裂缝,运用两期遥感影像建立三维视图,直观展示塌陷坑、地裂缝,通过对比两期影像圈定的图斑,计算出塌陷坑面积、地裂缝长度及其变化,综合分析塌陷发展趋势,圈定该矿山塌陷区范围,及时为有关部门对矿山环境进行整治提供依据和技术支撑,同时也为该矿区生态环境的综合治理提供基础数据和科学依据。     

Origin of ground fissures in the Shanxi Graben System, Northern China

Since the 1950s, hundreds of ground fissures have occurred in the Shanxi Graben System in Northern China. The fissures and related subsidence and differential settlement have caused and are causing substantial damage to homes, agricultural land, roads, canals, and other infrastructure. Although generally similar in appearance, the fissures have different origins. (1) Some fissures coincide with northeast-trending faults. Trenching shows that the fissures extend into the near-surface faults, increasing vertical offset clay beds and other stratigraphic markers at depth, and therefore are probably the surface expression of fault movements. (2) Some fissures are demonstrably related to accelerated groundwater withdrawal. This is particularly apparent in Xi'an City where groundwater levels have declined by about 15 m within 4 years. (3) Other fissures owe their origin to the well-known process of ‘soil collapse’. This is particularly common in the silty loessial sediments that occur within most of the valleys that comprise the Shanxi Graben System.     

Survey and monitoring of landslide displacements by means of L-band satellite SAR interferometry

This paper illustrates the capabilities of L-band satellite SAR interferometry for the investigation of landslide displacements. SAR data acquired by the L-band JERS satellite over the Italian and Swiss Alps have been analyzed together with C-band ERS-1/2 SAR data and in situ information. The use of L-band SAR data with a wavelength larger than the usual C-band, generally considered for ground motion measurements, reduces some of the limitations of differential SAR interferometry, in particular, signal decorrelation induced by vegetation cover and rapid displacements. The sites of the Alta Val Badia region in South Tyrol (Italy), Ruinon in Lombardia (Italy), Saas Grund in Valais (Switzerland) and Campo Vallemaggia in Ticino (Switzerland), representing a comprehensive set of different mass wasting phenomena in various environments, are considered. The landslides in the Alta Val Badia region are good examples for presenting the improved performance of L-band in comparison to C-band for vegetated areas, in particular concerning open forest. The landslides of Ruinon, Saas Grund, and Campo Vallemaggia demonstrate the strength of L-band in observing moderately fast displacements in comparison to C-band. This work, performed with historical SAR data from a satellite which operated until 1998, demonstrates the capabilities of future planned L-band SAR missions, like ALOS and TerraSAR-L, for landslide studies.     

Interacting tectonics,hydrogeology and karst processes in an intramontane basin: the Jiloca graben (NE Spain)

The Jiloca basin is a NNW–SSE trending, Neogene-Quaternary graben in NE Spain, bounded by normal faults with measurable hectometre-scale throws. Its overall trend truncates previous NW–SE folds. The sedimentary infilling includes Neogene and Quaternary deposits, exceeding 80 m in thickness. The stratigraphical and structural setting controls hydrogeology of the basin. Neogene marls constitute an aquiclude that separates a main Jurassic karstic, confined aquifer from a shallow, unconfined Plio-Quaternary aquifer. The Jurassic aquifer is laterally compartmented by impervious Upper Triassic anticline cores, though its piezometric surface usually lies 30–60 m higher than the Mesozoic-Neogene boundary. The geological, and specifically the hydrogeological features are not significantly compatible with a previously published hypothesis that considers the Jiloca depression as a polje (in which the final topography is the result of suballuvial karstic corrosion) for three reasons. First, the hypothetical corrosion front shows neither a specific relationship with the epiphreatic zone, nor control by the local presence of impervious Triassic rocks. Second, chemistry of groundwater at the underlying Jurassic aquifer would not allow limestone dissolution at rates necessary for producing the supposed erosion deepening of 300 m since the late Pliocene. Finally, no evidence of swallow holes or ponors has been found.     

Deciphering potential groundwater zone in hard rock through the application of GIS

Remote Sensing and Geographic Information System has become one of the leading tools in the field of hydrogeological science, which helps in assessing, monitoring and conserving groundwater resources. It allows manipulation and analysis of individual layer of spatial data. It is used for analysing and modelling the interrelationship between the layers. This paper mainly deals with the integrated approach of Remote Sensing and geographical information system (GIS) to delineate groundwater potential zones in hard rock terrain. The remotely sensed data at the scale of 1:50,000 and topographical information from available maps, have been used for the preparation of ground water prospective map by integrating geology, geomorphology, slope, drainage-density and lineaments map of the study area. Further, the data on yield of aquifer, as observed from existing bore wells in the area, has been used to validate the groundwater potential map. The final result depicts the favourable prospective zones in the study area and can be helpful in better planning and management of groundwater resources especially in hard rock terrains.     

The changing role of hydrogeology in semi-arid southern and eastern Africa

Much of southern and eastern Africa is semi-arid and heavily groundwater dependent. Borehole drilling commenced over a hundred years ago with magnetic and electrical resistivity surveys for borehole siting being introduced from 1936. Formalised training of hydrogeologists led in the 1970s to an almost standard approach to hydrogeological investigation and a period of stability followed, during which some major investigations were carried out. A period of decentralisation and fragmentation has since taken place in many parts of southern and eastern Africa, and groundwater monitoring and management are inadequate in many countries. All but six of the 14 SADC (Southern African Development Community) member states reportedly have an adequate monitoring network in place. However, groundwater demand is increasing and hydrogeologists need to promote the use of appropriate methodologies as an essential part of tackling the severe issues now facing the water sector in the region.     

新技术在城市地面沉降研究中的应用：遥感卫星雷达干涉测量（InSAR）

本文综述了遥感卫星合成孔径雷达（SAR）干涉测量及差分干涉测量的基本原理，针对近年来国外InSAR在地面沉降方面的研究成果，重点讨论了D－InSAR在国内大中城市进行地面沉降监测应用的可能性，对SAR数据的获取方法进行了阐述，并对这种方法目前的进展及未来应用前景进行了探讨。     

Remote sensing and GIS based determination of groundwater dependent ecosystems in the Western Cape, South Africa

Finding the location of groundwater dependent ecosystems (GDEs) is important in determining the extent of restrictions that need to be placed upon the abstraction of groundwater. Remote sensing was combined with geographical information system (GIS) modelling to produce a GDE probability rating map for the Sandveld region, South Africa. Landsat TM imagery identified the areas indicating the probable presence of GDEs and GIS assisted in their delineation. Three GIS models were generated: a GIS model predicting landscape wetness potential (LWP model) based on terrain morphological features; the LWP model was modified to highlight groundwater generated landscape wetness potential (the resulting GglWP model); and a groundwater elevation model was interpolated, combining groundwater level measurements in boreholes in the region with digital elevation model data. Biomass indicators generated from Landsat were classified and combined with the GIS models, followed by field verification of riverine and wetland GDEs. The LWP model provided the most accurate results of the three models tested for GDEs in this region.

The spa Deutsch-Altenburg and the hydrogeology of the Vienna basin (Austria)

 Some years ago the thermal water wells of the spa Deutsch-Altenburg were considered the result of a local water circulation. Extensive measurements of the water chemistry, trace elements, and environmental isotopes combined with drillings in the river bed of the Danube resulted in the indication of a key position of the mineral thermal wells of Deutsch-Altenburg for the groundwater circulation in the entire Vienna basin. The proof of this fact demanded the inclusion of the complicated geological position of the basin into the argumentation. The historical background of Bad Deutsch-Altenburg is the Roman municipium Carnuntum. During the reign of the Roman emperor Marc Aurel (161-180 A.C.) Carnuntum became the largest Roman municipium northeast of Rome with about 50 000 inhabitants covering the areas of present-day villages Petronell and Deutsch-Altenburg due to its strategic and trade position. The town was totally destroyed during the era of "migration of nations." The land surface was farmland or meadows. The first document concerning the thermal water of Deutsch-Altenburg is an expertise of the medical faculty of the University of Vienna (1548). During the siege of Vienna by the Turkish army under Kara Mustafa (1683–84) Deutsch-Altenburg was again, destroyed. It was only at the end of the 19th century that the modern installation of the spa began. The healing thermal water with the highest content of sulfur in Austria made Deutsch-Altenburg one of the most well-known spas in the country. The archaeological excavation of Carnuntum is the largest in Austria. Received: 6 October 1995 · Accepted: 13 November 1995     

遥感技术在泥石流灾害勘查中的应用

本文以具体实例总结和列举了利用遥感图像进行泥石灾害调查的多种应用方法，通过这些方法，不仅对泥石流特征，泥石流灾害，暴发周期和规模做了深层次的解译和研究，而且获得了丰富的调查成果，总结了北京地区泥石流分布规律，活动特点及危害状况，本文还对遥感技术在21世纪地质灾害工作的应用做了简单论述。     

Development of a numerical groundwater flow model using SRTM elevations

Remotely-sensed elevation data are potentially useful for constructing regional scale groundwater models, particularly in regions where ground-based data are poor or sparse. Surface-water elevations measured by the Shuttle Radar Topography Mission (SRTM) were used to develop a regional-groundwater flow model by assuming that frozen surface waters reflect local hydraulic head (or groundwater potential). Drainage lakes (fed primarily by surface water) are designated as boundary conditions and seepage lakes and isolated wetlands (fed primarily by groundwater) are used as observation points to calibrate a numerical flow model of the 900 km² study area in the Northern Highland Lakes Region of Wisconsin, USA. Elevation data were utilized in a geographic information system (GIS) based groundwater-modeling package that employs the analytic element method (AEM). Calibration statistics indicate that lakes and wetlands had similar influence on the parameter estimation, suggesting that wetlands might be used as observations where open water elevations are unreliable or not available. Open water elevations are often difficult to resolve in radar interferometry because unfrozen water does not return off-nadir radar signals.     

合成孔径雷达干涉测量技术（InSAR）及其对城市遥感的意义

该文详细论述与分析了合成孔径雷达干涉测量（InSAR)的干涉几何特征及InSAR影像之间的相关性特征，着重阐述并分析了影响其地学监测方面的数据质量等相干技术问题，就InSAR开展上海城市地面沉降研究提出了基本思路，对InSAR城市遥感应用的潜在意义进行了分析和讨论。     

Groundwater risk intensity mapping in semi-arid regions using optical remote sensing data as an additional tool

Due to semi-arid to arid climatic conditions, Jordan has limited groundwater resources. As a result of agricultural activities and untreated wastewater, most of the groundwater in the karstic areas is microbiologically contaminated. Groundwater vulnerability, hazards, and risk intensity were mapped (scale 1:50,000) at a test site near the Jordan Rift Valley. The mapping included the use of optical remote sensing to complement conventional data in areas with poor data. LANDSAT ETM+ data, and colour and panchromatic aerial photographs at different scales were incorporated using visual image interpretation and digital image processing. The applicability of the different remote sensing data sources is discussed and recommendations for their usage are given. Information derived from digital images offers new opportunities for vulnerability and hazard assessment, particularly when related to land use, vegetation cover, urbanisation and infrastructure. The resulting maps indicate clearly the vulnerable areas and the “hot spots” of potential contamination in the test site and form an important basis for integrated groundwater management studies and the long-term planning of protective measures. The application and transferability of the European vulnerability approach (COST Action 620) to the test site in Jordan proved to be good, in general, although modifications were necessary to suit local conditions.

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Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorised users.

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Résumé La Jordanie ne dispose que de ressources limitées en eaux souterraines, étant donné le climat semi-aride à aride prévalant dans ce pays. La contamination microbiologique de la plupart des eaux souterraines des régions karstiques est due aux activités agricoles et l’absence de traitement des eaux usées. La vulnérabilité des eaux souterraines, et le danger et l’intensité du risque de leur contamination ont été cartographiés (à l’échelle de 1:50 000) pour un site d’étude situé près de la vallée du Rift du Jourdain. La cartographie inclut l’utilisation de données optiques de télédétection pour complémenter les sources de données conventionnelles, dans les zones où la couverture est déficiente. Des données de LANDSAT ETM+ et des photographies aériennes en couleur et panchromatiques à différentes échelles ont été incorporées en utilisant des méthodes d’interprétation visuelle et informatique de l’image. La qualité des différentes sources de données de télédétection est discutée et évaluée, et des recommandations pour leur utilisation sont suggérées. L’informations obtenue des images digitales offre de nouvelles opportunités pour l’évaluation des vulnérabilités et des dangers, surtout reliés à l’usage du sol, la couverture végétale, l’urbanisation et les diverses infrastructures. Les cartes ainsi obtenues indiquent clairement les zones vulnérables et les points critiques potentiels pour la contamination du site d’étude et forment une base importante pour l’étude de la gestion intégrée des eaux souterraines et pour la planification à long terme des mesures de protection. L’applicabilité de l’approche européenne de cartographie de la vulnérabilité et des risques (COST action 620) au site d’étude jordanien est généralement approprié, même si certaines modifications ont été nécessaires pour s’ajuster aux particularités régionales.

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Resumen Los recursos hídricos subterráneos en Jordania son limitados debido principalmente a su clima semi árido. En la mayoría de las áreas kársticas, las aguas subterráneas están contaminadas microbiológicamente a consecuencia de la actividad agrícola y de las aguas residuales. Por ello, se han realizado mapas de peligro, vulnerabilidad e intensidad del riesgo (a escala 1/50.000) de un área piloto próxima al Rift en Jordania. Los mapas han sido elaborados con el apoyo de técnicas de teledetección en aquellas zonas donde la información era escasa. Se han utilizado imágenes del LANDSAT ETM+ a y fotografía aérea, de color y pancromática, a diferentes escalas para el procesamiento de las imágenes digitales y la fotointerpretación. En este trabajo se discute y se dan recomendaciones sobre la aplicabilidad de las diferentes imágenes de satélite en los análisis de teledetección. Los datos que se pueden derivar de las imágenes digitales son un avance para la evaluación de la vulnerabilidad y los peligros de contaminación, particularmente aquellos referidos a usos del suelos, cubierta vegetal e infraestructuras urbanas. Los mapas resultantes muestran claramente la vulnerabilidad y los peligros potenciales de contaminación en la zona de estudio, lo que genera una importante base para los estudios de gestión integrada de las aguas subterráneas y de planificación de las medidas protectoras. La aplicabilidad de la aproximación europea a los estudios de vulnerabilidad en karst (COST Action 620) en la zona de estudio (Jordania) es buena, aunque fueron necesarias algunas leves modificaciones de la metodología para ajustarla a las condiciones locales.

     

Mapping of hard rock aquifer system and artificial recharge zonation through remote sensing and GIS approach in parts of Perambalur District of Tamil Nadu,India

Mapping of hard rock aquifer system and artificial recharge zonation were carried out in an area of 325 km^2 in parts of the Perambalur District,Tamil Nadu,India.This district has been declared as one of the over-exploited regions in Tamil Nadu by the Central Groundwater Board.To raise the groundwater level,suitable recharge zones were identified and artificial recharge structures are suggested using geomatics technology in the present study.To this end,various thematic maps concerning lithology,soil,geomorphology,land use,land cover,slope,lineament,lineament density,drainage,drainage density and groundwater depth level were prepared.Fissile hornblende gneiss(244 km^2)covered most of the study area followed by charnockites(68 km^2).Structural hills and rocky pediments characterize the major geomorphological features in the targeted area,and are followed by deep moderated pediments.The area is mostly used as crop and fallow land,followed by scrub land and deciduous forest.In the study area,the slopes are predominantly very gentle(142 km^2)and nearly level(66 km^2)ones.Besides,Groundwater level data of 58 wells have been generated,in which the minimum and maximum depth were 3 and 28 m respectively.Integration under the GIS environment has been carried out using all the thematic layers to identify the groundwater prospect zone through the introduction of weight and rank methods.Integrated output performances were classified into very poor,poor,moderate,good and excellent categories.All these classes were further divided into two groups as suitable and non-suitable area for the selection of recharge sites.Hard rock fractures were mapped as lineaments from satellite images,and besides that,rose diagram was also generated to find out the trend of the fracture.Furthermore,fracture data of 146 numbers have been collected using Brunton compass to generate rose diagram and were correlated with the rose diagram derived from lineaments.The present study significantly brought up a few areas such as Ammapalayam,Melapuliyur,Senjeri and around Siruvachur for artificial recharge.