Vulnerability assessment of the karst aquifer feeding the Pertuso Spring (Central Italy): comparison between different applications of COP method

Karst aquifers vulnerability assessment and mapping are important tools for improved sustainable management and protection of karst groundwater resources. In this paper, in order to estimate the vulnerability degree of the karst aquifer feeding the Pertuso Spring in Central Italy, COP method has been applied starting from two different discretization approaches: using a polygonal layer and the Finite Square Elements (FSE). Therefore, the hydrogeological catchment basin has been divided into 72 polygons, related to the outcropping lithology and the karst features. COP method has been applied to a single layer composed by all these polygons. The results of this study highlight vulnerability degrees ranging from low to very high. The maximum vulnerability degree is due to karst features responsible of high recharge and high hydraulic conductivity. Comparing the vulnerability maps obtained by both methodologies it is possible to say that the traditional discretization approach seems to overestimate the vulnerability of the karst aquifer feeding the Pertuso Spring. Between the two different approaches of COP method, the proposed polygonal discretization of the hydrogeological basin seems to be more suitable to small areas, such as the Pertuso Spring hydrogeological basin, than the traditional grid mapping

Integrated approach of hydrogeomorphology and GIS mapping to the evaluation of ground water resources: an example from the hydromineral system of Caldas da Cavaca, NW Portugal.

Understanding the role of geomorphology is essential to accurately assess hydrogeological systems and groundwater resources. Hard-rock watersheds provide a source of valuable water resources. They commonly exhibit complex geological bedrock and morphological features as well as distinctive gradients in rainfall and temperature. A comprehensive evaluation and integrated gro undwater resources study has been carried out for Caldas da Cavaca hydromineral system in NW Portugal, using hydrogeomorphology and GIS mapping techniques. Thematic maps were prepared from satellite imagery, topographical and geological mapping and other hydrogeological field data. These maps were converted to GIS format a nd then integrated using GIS software with the purpose of elaborating a hydrogeomorphological map intended to delineate the infiltration potential areas for the study region. Finally, this study highlights the importance of hydrogeomorphological cartography and groundwater GIS mapping as useful tools to support hydrogeological surveys, as well as for decision-making in the scope of management plans respecting to land and water resources and groundwater sustainability

Groundwater Potential Mapping of the Major Aquifer in Northeastern Missan Governorate, South of Iraq by Using Analytical Hierarchy Process and GIS

As a result of the increasing demand for water in recent years, particularly after the emergence of drought conditions in Iraq, water policies in neighboring countries and the need to expand the uses of water for the purpose of food security, there is a truly urgent need for reassessment of groundwater resources in the light of modern efficient techniques for better managing and protecting of the aquifer system. In this study an attempt was made to delineate groundwater availability zones for the major aquifer in northeast Missan governorate, south of Iraq using GIS and analytical hierarchy process (AHP) decision making technique. Because of the data lacking, a total set of four criteria/features believed to be influencing groundwater productivity in the area were selected and mapped to demarcate groundwater potential classes after assign appropriate weights using AHP. All thematic layers were integrated and analyzed in ArcGIS 9.3 software. The final groundwater potential map was produced by linear weighted combination technique. The delineated groundwater potential map was finally verified using the available abstraction rates of existing wells. The prediction accuracy of the developed model was 72%. The groundwater potential map of the study area reveals three distinct zones: high, moderate, and low groundwater availability. The areas covered by these zones were 1138, 554, and 157 km2 for low, moderate, and high zones, respectively. The results demonstrate that the groundwater resources in the study area require careful management and pumping extraction plans. The generated model will help as a guideline for designing a suitable groundwater exploration plan in the future and thereby help efficient planning of scare groundwater in the study area. Keywords: Groundwater, GIS, AHP, Missan governorate, Ira

Spatial assessment of termites interaction with groundwater potential conditioning parameters in Keffi, Nigeria

© 2019 Elsevier B.V. Termite mounds are traditionally presumed to be good indicators of groundwater in places they inhabit but this hypothesis is yet to be scientifically substantiated. To confirm this assertion, it is expected that termite mounds would have strong correlations with groundwater conditioning parameters (GCPs). In this study, termite mounds distribution covering an area of about 156 km2 were mapped and their structural characteristics documented with the aim of examining their relationships with twelve (12) chosen GCPs. Other specific objectives were to identify specific mound types with affinity to groundwater and to produce a groundwater potential map of the study area. To achieve this, 12 GCPs including geology, drainage density, lineament density, lineament intersection density, land use/land cover, topographic wetness index (TWI), normalized difference vegetation index (NDVI), slope, elevation, plan curvature, static water level and groundwater level fluctuation were extracted from relevant sources. Frequency ratio (FR) and Spearman's rank correlation were used to find relationships and direction of such relationships. The result revealed a consistent agreement between FR and Spearman's rank correlation that tall (≥1.8 m) and Cathedral designed mounds are good indicators of groundwater. Further, the groundwater potential map produced from the Random Forest (RF) model via Correlation-based Feature Selection (CFS) using best-first algorithm depicted an erratic nature of groundwater distribution in the study area. This was then classified using natural break into very-high, high, moderate, low and very low potential classes and area under curve (AUC) of the receiver operating characteristics (ROC) showed an 86.5% validity of the model. About 75% of mapped termite mounds fell within the very-high to moderate potential classes thereby suggesting that although tall and cathedral mounds in particular showed good correlations with a number of GCPs, high mound density in a locality is also an indication of good groundwater potential

Rapid methods of landslide hazard mapping : Fiji case study

A landslide hazard probability map can help planners (1) prepare for, and/or mitigate against, the effects of landsliding on communities and infrastructure, and (2) avoid or minimise the risks associated with new developments. The aims of the project were to establish, by means of studies in a few test areas, a generic method by which remote sensing and data analysis using a geographic information system (GIS) could provide a provisional landslide hazard zonation map. The provision of basic hazard information is an underpinning theme of the UN’s International Decade for Natural Disaster Reduction (IDNDR). It is an essential requirement for disaster preparedness and mitigation planning. This report forms part of BGS project 92/7 (R5554) ‘Rapid assessment of landslip hazards’ Carried out under the ODA/BGS Technology Development and Research Programme as part of the British Government’s provision of aid to developing countries. It provides a detailed technical account of work undertaken in a test area in Viti Levu in collaboration with Fiji Mineral Resources Department. The study represents a demonstration of a methodology that is applicable to many developing countries. The underlying principle is that relationships between past landsliding events, interpreted from remote sensing, and factors such as the geology, relief, soils etc provide the basis for modelling where future landslides are most likely to occur. This is achieved using a GIS by ‘weighting’ each class of each variable (e.g. each lithology ‘class’ of the variable ‘geology’) according to the proportion of landslides occurring within it compared to the regional average. Combinations of variables, produced by summing the weights in individual classes, provide ‘models’ of landslide probability. The approach is empirical but has the advantage of potentially being able to provide regional scale hazard maps over large areas quickly and cheaply; this is unlikely to be achieved using conventional ground-based geotechnical methods. In Fiji, landslides are usually triggered by intense rain storms commonly associated with tropical cyclones. However, the regional distribution of landslides has not been mapped nor is it known how far geology and landscape influence the location and severity of landsliding events. The report discusses the remote sensing and GIS methodology, and describes the results of the pilot study over an area of 713 km2 in south east Viti Levu. The landslide model uses geology, elevation, slope angle, slope aspect, soil type, and forest cover as inputs. The resulting provisional landslide hazard zonation map, divided into high, medium and low zones of landslide hazard probability, suggests that whilst rainfall is the immediate cause, others controls do exert a significant influence. It is recommended that consideration be given in Fiji to implementing the techniques as part of a national strategic plan for landslide hazard zonation mapping

Appraisal of Ground Water Potential through Remote Sensing in River Basin, Pakistan

Groundwater is an important source of water supply throughout the world and is one of the vital parts of the hydrological cycle. Its availability depends on the precipitation and recharge conditions. In arid regions, recharge amount is smaller than semiarid regions. Recharge is the basic phenomenon for the sustainability of ground water resources. Pakistan has inadequate water resources and inflow pattern due to arid climate. There are so many factors which make the conditions gradually worst such as increasing population, change in climate condition and misuse of water resources etc. These factors lead to the situation of water scarcity rather than any addition. watershed is positioned at the boundary of Sindh and Balochistan, Pakistan. It is the most important water supply source to Industrial area and the mega city of Karachi, which is getting only about 50 percent of water supply against its fast-increasing requirement. Hab watershed is therefore considered for this study. Remote Sensing and GIS are very effective tools for the assessment and exploration of potential sites of groundwater in any of the watershed. A case study was conducted for the assessment of groundwater potential sites in study area. For this purpose, different thematic layers were created like drainage map, structural and geological map and Overlay analysis was performed and to determine the potential zone of groundwater in the study area

Use of GIS to Estimate Recharge and Identification of Potential Groundwater Recharge Zones in the Karstic Aquifers, West of Iran

Estimating and studying groundwater recharge is necessary and important for the management of water resources. The main aim of this work is to estimate the value of the annual recharge in some parts of the Kermanshah and Kurdistan province located in the west of Iran. There are many approaches available for estimation of the recharge, but RS (remote sensing) and GIS (geographic information system) have provided and combined a lot of effective spatial and temporal data of large areas within a short time. For this purpose, nine information layers including the slope, aspect of slope, lithology, lineament density, drainage density, precipitation, vegetation density, soil cover, and karst features were prepared and imported to the ArcMap software. After preparing the information layers, they have to weigh based on their effects on the value of the recharge. In order to be weighted the different parameters, methods of judgment expert, reciprocal influences of parameters, and AHP were used. Using GIS, the results obtained from the final map indicated the average value for the recharge based on the average calculated coefficient of recharge. The annual recharge coefficient in the study area was estimated to be between 30% and 80%