Identification of suitable sites for groundwater recharge in Awaspi watershed using GIS and remote sensing techniques

Groundwater is a valuable natural resource for drinking, domestic, livestock use, and irrigation, especially in arid and semi-arid regions like the Garmiyan belt in Kurdistan region. The Awaspi watershed is located 50 km east of Kirkuk city, south Kurdistan, Iraq; and covers an area of 2146 km². The paper presents result of a study aimed at: (1) mapping and preparing thematic layers of factors that control groundwater recharge areas, and (2) determination of sites suitable for groundwater recharge. We used available data such as geological map, groundwater depth map, digital elevation model (DEM), Landsat 8 imagery, and tropical rainfall measuring mission (TRMM) data for this study. These data, supplemented by slope features, lithology, land use land cover, rainfall, groundwater depth, drainage density, landform, lineament density, elevation and topographic position index, were utilized to create thematic maps to identify suitable areas of groundwater recharge, using GIS and remote sensing techniques. Analytic hierarchy process (AHP) was applied to weight, rank, and reclassify these maps in the ArcGIS 10.3 environment, to determine the suitable sites for groundwater recharge within the Awaspi watershed. Fifty-five percent of the total area of the watershed was found to be suitable for groundwater recharge; whereas 45% of the area was determined to have poor suitability for groundwater recharge, but can be used for surface water harvesting.     

基于GIS的建设项目地质灾害危险性评估

经济的快速发展使人类活动导致的地质灾害问题越来越严重,建设项目是目前人类活动的一项重要内容,国家已明确要求对建设项目进行地质灾害危险性评估。针对目前建设项目地质灾害危险性评估大多处于定性评估阶段的现状,提出利用GIS技术进行建设项目危险性评估。以桂西某县冶金化工加工厂建设项目为例,设计了基于GIS的地质危险性评估模型,详细介绍了评估过程,并通过GIS技术实现了评估结果的可视化显示。实践证明,GIS技术可为建设项目地质灾害危险性的定量评估和可视化输出提供科学的表现方法。     

Identification of suitable sites for open and bore well using ground magnetic survey

The study aims to identify a suitable site for open and bore well in a farmhouseusing ground magnetic survey in south India. It also aims to define depth to granitoid and structural elements which traverse the selected area. Magnetic data(n=84) measured, processed and interpreted as qualitative and quantitatively. The results of total magnetic intensities indicate that the area is composed of linear magnetic lows trending NE-SW direction and circular to semi-circular causative bodies. The magnetic values ranged from -137 nT to 2 345 nT with a mean of 465 nT. Reduction to equator shows significant shifting of causative bodies in the southern and northern directions. Analytical signal map shows exact boundary of granitic bodies. Cosine directional filter has brought out structural element trending NE-SW direction.Results of individual profile brought to light structurally weak zone between 90 m and 100 m in all the profile lines. Sudden decrease of magnetic values from 2 042 nT to 126 nT noticed in profile line 6 between 20 m and 30 m indicates fault occurrence. Magnetic breaks obtained from these maps were visualized,interpreted and identified two suitable sites for open and bore well. Radially averaged power spectrum estimates depth of shallow and deep sources in 5 m and 50 m, respectively. Euler method has also been applied to estimate depth of granitoid and structural elements using structural indexes 0, 1, 2, and 3 and found depth ranges from 10 m to 90 m. Study indicates magnetic method is one of the geophysical methods suitable for groundwater exploration and site selection for open and borewells.     

Knowledge based systems for risk assessment of the subsurface of contaminated sites

Computer-based risk evaluation methods are practical tools to compare automatically and evaluate contaminated sites. HYDRISK is an example of adequate knowledge-based systems: HYDRISK evaluates hydrogeological properties and chemical criteria relevant to contaminant transport with respect to the necessary remedial actions. It works at a high investigative level and enables geologists and engineers to draw differentiated conclusions for selecting remediation methods for the contaminated site. HYDRISK emphasizes space and time dependent aspects of the contaminant transport. It is supported by a geographic information system (GIS) to display the evaluation results. Some ideas on considering the spatiotemporal variability of relevant parameters by means of geostatistical methods and numerical models will be given.     

Influential factors in evaluating the construction pore pressure in earth dams by using UDAM program

The aim of this article is to discuss about the influential parameters affecting the state of the pore pressure within the low permeability section of an earth dam body during the periods of construction, immediately after construction, and also during some times elapsing after construction. Because the condition of soil in constructing earth dams is usually unsaturated, so the matter of unsaturated soils should be considered here and a special finite element program suitable to this topic needs to be applied. The finite element program used in this study is the UDAM finite element program which has been compiled specifically for illustrating the behavior of unsaturated soils. The results of the UDAM computations are discussed in view of the pore water pressure developed within the body of dam slope during the stages of construction, and its maximum positive values immediately after the construction and its variations in the post-construction times are shown. Because the positive pore pressure decreases the shear strength of soil and the negative pressure (i.e. suction) increases the strength, the state of slope stability is correlated with the influential factors which can affect the situation of pore pressure distribution within a given section. Therefore, based on the present computations, the effect of height of embankment, initial degree of saturation, coefficient of permeability, degree of compaction and finally the effect of elapsing time are illustrated.     

Managed aquifer recharge (MAR) by the construction of subsurface dams in the semi-arid regions: A case study of the Kalangi river basin, Andhra Pradesh

Overuse of groundwater in coastal areas, due to high population and agricultural activity results in seawater intrusion into the coastal aquifer. This paper presents the control measures taken to manage aquifer recharge (MAR) and also to overcome the problem of seawater intrusion into the coastal aquifer along the Kalangi river, Nellore district of Andhra Pradesh, India having connectivity with Pulicat (saltwater) lake estuary. Due to overexploitation of groundwater and less rainfall in past years, adjacent seawater has started intruding in the Kalangi river sub-surface and deteriorating groundwater quality up to 11.6 km from the confluence of the river with Pulicat lake. To prevent this situtation, subsurface dams were constructed in traditional manner using local earth material in three different places across the Kalangi river near Sullurpet town. The water storage capacities calculated after the sub-surface dams’ construction are 1.28 mcft at GK Engineering College, 6.23 mcft at Challamagudi and 3.143 mcft at Holy Cross School sites. The Holy Cross School sub-surface dam is the first full scale dam-cum-check dam constructed to prevent salt water intrusion in the Kalangi river at Sullurpet, Nellore district, Andhra Pradesh. At the Kalangi river estuary portion (at the mouth of sea) a groyne was reconstructed over old groyne site with the introduction of clay bed and wooden sheet piles at down stream. Apart from prevention of sea water entry into Kalangi river sub-surface (during seasons) the groyne top level was raised to prevent mixing of high sea water tides with fresh water and ensuring additional storage of fresh water at upstream side. The reconstructed groyne was serving the purpose of obstructing the surface seawater entry in the Kalangi river and water quality has improved in the river as well as in the wells. After construction of sub-surface dam, as per the Simpson ratio classification, there is substantial improvement of water quality in the SHAR infiltration well situated near the Holy Cross School sub-surface dam.     

Evaluating Boolean,AHP and WLC methods for the selection of waste landfill sites using GIS and satellite images

The city of Saqqez has a population of 140,000 people, making it one of the largest cities in Iran. Population growth, consumerism, and change in eating habits, such as the increased use of packaged products, is causing the accumulation of waste in this city to increase. In this study, the selection of a waste landfill site for Saqqez focused on 13 layers of geography information that was used by the IDRISI and Arc GIS software. Different models of the analytic multi-criteria decision-making process, such as an analytical hierarchy process (AHP), weighted linear combination (WLC), and Boolean logic, were used to manage layers to establish specific databases for urban waste landfills. Satellite images (Landsat ETM⁺ and SPOT 5), proposed sites and a land use map of the study area were also used. The results of this study indicated that two methods (AHP and WLC) in the early stages had better decision-making powers for locating landfill sites when compared to Boolean logic. Overlapping and compounding the similarities between these models in Arc GIS software, a 74-ha site was found. This site will be able to accept 130 tons of waste per day for the next 20 years.     

中国花岗岩地理信息系统建设的探讨

讨论了中国花岗岩地理信息系统建设方案。在全面收集、综合、分析、整理中国花岗岩地质资料的基础上，对地质图属性信息进行合理的分类及编码，分别建立花岗岩的属性与图形数据，并在空间信息与属性信息之间建立正确的连接，运用计算机及其网络通讯技术，形成中国花岗岩地理信息系统，实现根据区域、地层、构造、岩石、矿产、地球物理、地球化学等属性对花岗岩地质图的信息进行灵活检索。在建立数据库的基础上，在Internet上建立中国花岗岩专业网站，使花岗岩地质信息的在线服务成为可能。     

Locating hazardous waste treatment facilities and disposal sites in the State of Yucatan,Mexico

In this work, geographic information systems (GIS) and multi-criteria decision analysis (MCDA) were used in order to identify the appropriate location for hazardous waste (HW) treatment facilities and final disposal sites in the State of Yucatan, Mexico. For HW-treatment facilities, in addition to the distance to generators and treatment facilities, geographic conditions of the site, such as vegetation, soil type, accessibility, distance to urban or rural communities, and all the boundary elements as agricultural or livestock areas, were considered in GIS and MCDA. Final disposal was taken into account only for those HW that could not be avoided or treated. In order to find the most suitable areas, the Mexican Official Norm NOM-055-SEMARNAT-2003 criteria were observed too. It was found that the most suitable zones for HW-treatment facilities were at the centre of the State, whereas the most recommended areas for HW final disposal sites were at the south.     

Risk assessment of cultural heritage sites clusters using satellite imagery and GIS: the case study of Paphos District,Cyprus

This paper aims to assess the risk of natural and anthropogenic hazards for cultural heritage in Cyprus by integrating multi-temporal GIS and earth observation analysis, in the area of Paphos District. The work presented here attends to re-evaluate previous results from earth observations and GIS analysis and go a step forward targeting more reliable outcomes for cultural heritage management. The scope of the paper was to develop a more accurate methodology for risk assessment against natural and anthropogenic hazards (e.g., soil erosion; urban expansion), based on homogeneous clustering of the monuments under consideration. The accomplished assessment approach, being lopsided and generic, cannot be applied across the board and undistractedly for cultural heritage management of all types of monuments of the district. Instead, the proposed clustering of monuments based on a variety of parameters is taking into consideration characteristics of their immediate environment, resulting rational local-based outcomes more useful for monuments and sites safeguarding and for prevention measurements. For each one of the five clusters of monuments located in the Paphos District, an analytical hierarchy process (AHP) method was followed in order to address the individual and unique characteristics of the monuments and sites within the same cluster area. Subsequently, the weight factors from these clusters were interpolated to the whole district, prior to the application of the overall AHP risk assessment. Ultimately, the results were compared with the overall AHP method applied for the entire Paphos District, indicating that the proposed methodology can be more accurate and realistic for the different groups of the monuments.     

Seismic hazard map of Coimbatore using subsurface fault rupture

This study presents the future seismic hazard map of Coimbatore city, India, by considering rupture phenomenon. Seismotectonic map for Coimbatore has been generated using past earthquakes and seismic sources within 300 km radius around the city. The region experienced a largest earthquake of moment magnitude 6.3 in 1900. Available earthquakes are divided into two categories: one includes events having moment magnitude of 5.0 and above, i.e., damaging earthquakes in the region and the other includes the remaining, i.e., minor earthquakes. Subsurface rupture character of the region has been established by considering the damaging earthquakes and total length of seismic source. Magnitudes of each source are estimated by assuming the subsurface rupture length in terms of percentage of total length of sources and matched with reported earthquake. Estimated magnitudes match well with the reported earthquakes for a RLD of 5.2% of the total length of source. Zone of influence circles is also marked in the seismotectonic map by considering subsurface rupture length of fault associated with these earthquakes. As earthquakes relive strain energy that builds up on faults, it is assumed that all the earthquakes close to damaging earthquake have released the entire strain energy and it would take some time for the rebuilding of strain energy to cause a similar earthquake in the same location/fault. Area free from influence circles has potential for future earthquake, if there is seismogenic source and minor earthquake in the last 20 years. Based on this rupture phenomenon, eight probable locations have been identified and these locations might have the potential for the future earthquakes. Characteristic earthquake moment magnitude (M _w ) of 6.4 is estimated for the seismic study area considering seismic sources close to probable zones and 15% increased regional rupture character. The city is divided into several grid points at spacing of 0.01° and the peak ground acceleration (PGA) due to each probable earthquake is calculated at every grid point in city by using the regional attenuation model. The maximum of all these eight PGAs is taken for each grid point and the final PGA map is arrived. This map is compared to the PGA map developed based on the conventional deterministic seismic hazard analysis (DSHA) approach. The probable future rupture earthquakes gave less PGA than that of DSHA approach. The occurrence of any earthquake may be expected in near future in these eight zones, as these eight places have been experiencing minor earthquakes and are located in well-defined seismogenic sources.     

利用地震P波确定煤层瓦斯富集带的分布

查明煤层瓦斯富集区域,对可能的瓦斯突出点进行预报,是当前煤矿生产中亟待解决的重要课题。利用地震P波对裂缝性地层所表现出的方位各向异性特征,根据地震属性随方位角变化可以预测裂隙发育方向和密度的基本原理,应用多种地震P波方位属性预测裂隙发育带。通过对淮南张集煤矿西三采区三维地震P波资料的处理,获得6个方位地震数据体,从中提取多种与煤层和围岩裂隙相关的地震属性,并计算出裂隙的发育方向和密度,为确定瓦斯富集带的分布提供了一种新的途径。     

Locating the sources of potential fields in areal data using the singularity method

In an effort to develop and improve potential geophysical field interpretation we suggest that the singularity method should be extended toward areal data. This procedure enables mass and fast calculation of singularities in area and stable solutions. Studying the behavior of model fields and localization of singularities in the phase planes of vector fields permits the use of findings in interpreting geopotential fields. Model and real-life cases of this procedure as applied to tectonic dislocations and local geologic features are exemplified. We show that the proposed procedure significantly enhances the application of the singularity method to interprete geopotential fields.     

Integrating surface and subsurface reconnaissance data in the study of stratigraphically complex sites: Blagotin,Serbia

This article demonstrates the application of multiple reconnaissance methods as an efficient means of localizing desired data sets (e.g., artifact concentrations and architectural features) in stratigraphically complex sites. Excavations at Blagotin, Serbia, are presented as an example. Blagotin is a multioccupation site with vertically superimposed and laterally displaced cultural deposits. The application of a battery of survey techniques and the integration of the results enabled the author to define periods of occupation (Early Neolithic, Eneolithic, Early Iron Age), distinguish temporal variations, and predict the nature and distribution of subsurface archaeological remains. Ultimately, the Early Neolithic occupation is shown to consist of a small settlement with a large central pit‐house surrounded by a ring of smaller pit houses. This interpretation of the intra‐settlement spatial organization, made possible through the application of a multiple survey technique, differs from those previously offered for these types of sites. © 2000 John Wiley & Sons, Inc.     

基于GIS的建设项目地质灾害危险性评估

为防灾减灾,研究建设项目地质灾害危险性的评估势在必行。以云南省某县的建设项目为例,将GIS技术引入,综合考虑研究区地形地貌、地层岩性、地质构造、工程地质条件、水文地质条件、人类工程活动等有关地质灾害的影响因素,判断评估区地质环境条件复杂程度。在此基础上,分别从地质灾害危险性现状评估、预测评估和综合分区评估逐一论述,将评估区划分为地质灾害危险性大区和地质灾害危险性中等区,并针对拟建项目提出相关的防治措施。得出:评估区现状地质灾害中等发育,工程建设及运营过程中可能加剧、引发和遭受的地质灾害危害性及危险性中等至大,建设用地总体适宜性为基本适宜。     

Detection and evaluation of horizontal fractures in earth dams using the self-potential method

The self-potential method can be applied to evaluate the degree of water seepage into earth or rockfill dams. Spatial distribution of measured self-potential data can indicate possible anomalous water flow. Phenomena, such as piping, can be modelled as cylindrical bodies. Internal erosion can develop structures, which can be represented by a sphere or point source. Differential settlement in the dam structure occasionally creates horizontal fractures, which require equivalent geometrical body formula. An equation, which allows the calculation of a self-potential profile over a horizontal contact, was developed. This equation can also be applied to the inspection of water flow into horizontal drainage filters. When inverse interpretation returns bodies of relatively small amplitudes, then their probability can be tested statistically. A test, based on cross-correlation between a modelled curve and field data, can be used to evaluate their existence at a given probability level. An acceptance criterion is computed, using the concept of likelihood coefficient. The equation was applied to two case histories. The first is an example of water flow evaluation into a horizontal drainage filter. Several anomalous bodies were interpreted from residual self-potential data, i.e. from the difference between the theoretical response of the filter and the measured self-potential values, then, most of the interpreted bodies were statistically tested. The second case deals with detection and evaluation of a horizontal fissure. The interpreted parameters of the detected body corresponded well to a horizontal fracture found when the water level in the reservoir was lowered.     

基于EnKF融合地球物理数据刻画含水层非均质性

含水层非均质性的刻画是模拟地下水中污染物运移的关键。以渗透系数为研究对象,构建了综合集合卡尔曼滤波方法、有效电阻率模型与地下水运移模型的同化框架,通过融合地球物理观测数据与污染物浓度观测数据来推估渗透系数的空间分布。基于理想算例,验证了该同化框架刻画含水层非均质渗透系数场的有效性,并针对不同初始参数信息与观测类型对比了耦合与非耦合水文地球物理方法的适用性。研究结果表明:基于集合卡尔曼滤波方法同化多种类型的观测数据,可有效地推估非均质参数空间分布。当初始信息较准确时,耦合方法的参数推估精度更高;初始信息存在偏差时,非耦合方法有更好的同化效果。由于非耦合方法计算成本较低且对初始信息缺失时适用性更强,在实际应用中可先基于非耦合方法初步估计参数,再利用耦合方法进一步提高参数推估精度。融合多种类型观测数据可有效提高参数推估效果。     

GIS and multi-criteria analysis to select potential sites of agro-industrial complex

The selection of the potential sites to the creation of an agro-industrial complex requires a large amount of spatial information. Geographical information systems are capable of managing this information, providing the ability to integrate multiple layers of information and deriving new ones. This study incorporates environmental, social, economic, geological and infrastructural data. A multi-criteria analysis is performed to select the potential sites to the creation of an agro-industrial complex in the city of Sfax (the southern coast of Tunisia). The comparison by pair method adopted in this paper, based on a linear combination pondered after having assigned to every factor of decision a coefficient of level-headedness, creates many scenarios among which we selected the sustainable development one. This scenario assigned the highest weight to the economical, environmental and social factors (0.3 for each factor), which shows the presence of nine suitable sectors for the creation of an agro-industrial complex. The ELECTRE method enabled us to make a site ordering for the identification of the most three appropriate sites.     

Integrating GIS and DSS for identification of suitable areas for artificial recharge,case study Meimeh Basin,Isfahan, Iran

Flood spreading is an inexpensive method for flood mitigation and artificial recharge of aquifers that results in a large budget return for relatively small investment.It is necessary to study some regional characteristics in order to determine the appropriate areas for artificial groundwater recharge by flood spreading in Meimeh Basin, Isfahan Province, Iran. Necessary regional characteristics to be studied are: slope, infiltration rate, sediment thickness, transmissivity, and water quality. In this research to identify suitable areas for artificial recharge several thematic layers were prepared, assigning each layer to one of the mentioned characteristics. The thematic layers were classified to several classes based on the existing criteria. All of the classes of the thematic layers were integrated and analyzed using a decision support system (DSS) in a geographical information system (GIS) environment. Finally suitability of the integrated classes for artificial recharge was identified in which the following classes were separated:(i) Very suitable, (ii) suitable, (iii) moderate suitability, and (iv) unsuitable.The validity of the generated model was verified by applying the model to a number of successful floodwater spreading stations throughout Iran. The verified model showed satisfactory results for all of the stations. The results for Meimeh Basin showed that about 70% of the Quaternary sediments in the studied area are suitable and moderately suitable for artificial recharge by flood spreading.