GIS-based Evaluation Research Articles

GIS-Based Evaluation of Landslide Susceptibility Models Using Certainty Factors and Functional Trees-Based Ensemble Techniques

The main purpose of this paper is to use ensembles techniques of functional tree-based bagging, rotation forest, and dagging (functional trees (FT), bagging-functional trees (BFT), rotation forest-functional trees (RFFT), dagging-functional trees (DFT)) for landslide susceptibility modeling in Zichang County, China. Firstly, 263 landslides were identified, and the landslide inventory map was established, and the landslide locations were randomly divided into 70% (training data) and 30% (validation data). Then, 14 landslide conditioning factors were selected. Furthermore, the correlation analysis between conditioning factors and landslides was applied using the certainty factor method. Hereafter, four models were applied for landslide susceptibility modeling and zoning. Finally, the receiver operating characteristic (ROC) curve and statistical parameters were used to evaluate and compare the overall performance of the four models. The results showed that the area under the curve (AUC) for the four models was larger than 0.74. Among them, the BFT model is better than the other three models. In addition, this study also illustrated that the integrated model is not necessarily more effective than a single model. The ensemble data mining technology used in this study can be used as an effective tool for future land planning and monitoring.

GIS 기반 토사유실 평가에서 지적정보 연계 방향

토사유실 평가시 이용되는 토지피복 정보는 식생피복인자와 경작인자를 계산하는데 이용된다. 지표를 구성하는 피복정보는 환경부에서 구축한 토지피복도가 활용되지만 예산 등의 문제로 주기적인 갱신이 어려운 문제가 있다. 본 연구에서는 GIS를 활용하여 남원시의 토사유실량을 계산하였다. 특히 토지피복의 최신성을 확인하기 위해 연속지적도를 활용하여 지목별 단위토사유실량을 검토하였으며, 그 결과 일부 토지피복에서 비 정상적인 토사유실량이 나타난 것을 알 수 있었다. 그리고 2003년부터 현재까지의 토지피복 변화를 살펴보기 위해 최근 개발이 진행된 공장용지와 유지를 대상으로 항공사진을 이용하여 확인하였다. 그 결과 2003년부터 현재까지 많은 지역에서 농공단지 건설 등이 이루어짐을 알 수 있었으며, 일부 농업용저수지도 함께 건설됨을 알 수 있었다. 이와 같이 일부 지자체의 경우 환경부 토지피복도 구축 시점이 오래되어 현실적으로 최신의 토지피복 특성을 반영하지 못하는 경우가 있는 것으로 나타났으며, 따라서 토사유실 평가시 최신의 지적도를 활용하여 일부 토지피복 정보를 대체하는 연구가 필요할 것으로 판단된다.

GIS-Based Evaluation of Groundwater Quality and Suitability in Dakhla Oases, Egypt

Groundwater is the main source for agricultural and domestic purposes in the Western Desert of Egypt. Groundwater quality is significantly influenced by the surrounding anthropogenic activities. This paper is one of the attempts to spatially assess groundwater quality and its suitability for drinking and irrigation in Dakhla Oases using Water Quality Index (WQI) and GIS techniques. Calibrated Landsat 8 OLI satellite images were processed to produce Land Use Cover map (LULC) to assess the agricultural and human activities in the study area. Further, eight groundwater quality parameters and WQI were attributed to a GIS layer for 71 investigated wells for mapping purposes using the Inverse Distance Weighting (IDW) method in ArcGIS. LULC map showed that 75% of the study area is a bare land and 25% is urban and agricultural areas. Almost all the studied wells recorded total dissolved solids and sulfate coinciding with the Egyptian permissible limits for drinking purposes. Fe and Mn levels exceeded the allowable limits for drinking in the majority of Dakhla wells. Based on the WQI, 38% and 36.6% of the study area fell within the poor water category according to the Egyptian and WHO standards, respectively. Most of the groundwater wells were of the best quality for irrigation with regard to salinity (less than 2000 mg/L) and the excellent quality in terms of sodium absorption ratio (< 10). It can be concluded that GIS analyses of groundwater quality and suitability can provide one of the necessary inputs for management and planning of Dakhla Oases and other similar regions.

Suitable Solid Waste Disposal Site Selection Using Geographical Information System (GIS): A Case of Debre Berhan Town, Ethiopia

Siting solid waste disposal is an extremely difficult task mainly due to the fact that the selection process involves many factors and strict regulations. Nevertheless, if not systematically and scientifically sited and managed properly, it will result in environmental and socio-economic problems. The town of Debre Berhan is currently using dumping site that has not been selected by scientific study which is environmentally sound and socio-economically acceptable. The main aim of this study is to find the suitable solid waste disposal site by using the GIS-based Multi Criteria Evaluation techniques in Debre Berhan town. Factors such as slope, depth to ground water table, permeability of soil, land use/ land cover, proximity from roads, proximity from ground water wells, proximity from water bodies were used for selecting suitable solid waste disposal site within the study area. The factor maps were reclassified and standardized in GIS environment followed by preparation of their suitability maps. The relative weights of factors were estimated using Analytical Hierarchy Process and factors maps were developed by using GIS spatial operations. Weighted Linear Combination was also used to integrate the factor maps and produce overall solid waste disposal suitability map. The final solid waste disposal site suitability map prepared in four suitability rank such as highly suitable, moderately suitable, low suitable and unsuitable. The result shows that around 3.81% area is under highly suitable for solid waste disposal site, 47.91% is moderate suitable and 15.91% area is unsuitable for suitable for solid waste disposal site. The results indicates that the method is capable of identifying locations highly suited for suitable for solid waste disposal site.

GIS-based locational evaluation of infrastructure facilities in hilly regions: a case study of an institute campus

Topography impacts the overall development of a hilly region. It plays a significant role in location-based decisions of infrastructure facilities. Present study explores the application of geographic information systems (GIS) in the topography modelling and the modelling of existing facilities. GIS facilitates the location-based evaluation of proposed facilities through geospatial analysis. The use of GIS facilitates construction professionals in organizing, interpreting and linking information to evaluate the locations of proposed infrastructure facilities. Critical aspects affecting LBE of infrastructure facilities identified through the existing literature and questionnaire survey were modelled for evaluating the locations of proposed infrastructure facilities in the campus layout of Jawaharlal Nehru Government Engineering College Sundernagar, Himachal Pradesh in India, as a case study. The use of GIS facilitates construction professionals in organizing, interpreting and linking information to evaluate the locations of proposed infrastructure facilities. Building codal provisions to consider topography and locations of already existing infrastructure facilities were modelled. GIS-based framework developed in the present study helped in identifying proposed infrastructure facilities which were located at adverse locations. This facilitates in taking corrective measures timely for re-locating these proposed infrastructure facilities more appropriately in hilly regions.

A GIS-based analysis of geographical accessibility to shared information and communications technology (ICT) infrastructure in a remote region of Nigeria

Shared ICT facilities provide alternative channels for accessing ICT services especially for the disadvantaged people who cannot afford the premium paid for personalized services. This study presents a GIS-based evaluation of geographical accessibility to shared internet and phone service centres in a remote and lagging region in Nigeria. Global Positioning System (GPS) location data were captured for settlements, phone and internet service centres and road network data were obtained for the study. Closest Facility solver in ArcGIS Network Analyst was employed to measure the accessibility of demand centres to existing phone service centres (telecentres) and Public Internet Access Centres (PIACs). The results showed that private actors are the main providers of shared ICT facilities in the study area. Moreover, a patron of ICT service needs to travel an average distance of 8.6 km to the nearest phone service centre and 17.2 km to the nearest PIAC to access these ICT services. The average distances that prospective patrons traverse to access phone and internet services are longer than the 5 km maximum prescribed by the universal access policy. Accessibility to shared ICT facilities remains poor in the remote rural areas. The government should consider innovative service delivery options like mobile telecentres to provide shared ICT facilities in these areas to foster inclusiveness in the new information society.

Research and implementation of a universal workflow model to evaluate the soil fertility based on OGC Web Service

ABSTRACTA method based on workflow technology and Open Geospatial Consortium (OGC) specification is proposed to establish a universal workflow conceptual model in the network environment. In this paper, the soil fertility evaluation conceptual model was developed as an evaluation method of soil fertility by analyzing the GIS-based fertility evaluation method and extracting the dynamic variable to verify the feasibility model. This validation process involves determining the instantiation of the conceptual model. The proposed conceptual model achieved the following goals. All data acquisition and processing functions were packaged into an OGC-compliant service model; these service models were organized into a processing chain in a certain order on the workflow platform by Petri-Net; the fertility evaluation was realized on the workflow platform by calling the processing chain. Results showed that processing functions and data can be shared in the network environment, and the network workflow model can be realized by the workflow technology. The successful implementation of fertility evaluation proved the feasibility of the network-based universal workflow conceptual model. In addition, the flexibility of our modeling method is demonstrated by reconstructing the workflow model.

Decarbonizing Energy in Bali With Solar Photovoltaic: GIS-Based Evaluation on Grid-Connected System

In the past century, fossil fuels have dominated energy supply in Indonesia. However, concerns over emissions are likely to change the future energy supply. As people become more conscious of environmental issues, alternatives for energy are sought to reduce the environmental impacts. These include renewable energy (RE) sources such as solar photovoltaic (PV) systems. However, most RE sources like solar PV are not available continuously since they depend on weather conditions, in addition to geographical location. Bali has a stable and long sunny day with 12 hours of daylight throughout the year and an average insolation of 5.3 kWh/m2 per day. This study looks at the potential for on-grid solar PV to decarbonize energy in Bali. A site selection methodology using GIS is applied to measure solar PV potential. Firstly, the study investigates the boundaries related to environmental acceptability and economic objectives for land use in Bali. Secondly, the potential of solar energy is estimated by defining the suitable areas, given the technical assumptions of solar PV. Finally, the study extends the analysis to calculate the reduction in emissions when the calculated potential is installed. Some technical factors, such as tilting solar, and intermittency throughout the day, are outside the scope of this study. Based on this model, Bali has an annual electricity potential for 32-53 TWh from solar PV using amorphous thin-film silicon as the cheapest option. This potential amount to three times the electricity supply for the island in 2024 which is estimated at 10 TWh. Bali has an excessive potential to support its own electricity demand with renewables, however, some limitations exist with some trade-offs to realize the idea. These results aim to build a developmental vision of solar PV systems in Bali based on available land and the region’s irradiation.&#x0D; Keywords: Energy modelling, solar PV, energy policy

Multicriteria Spatial Decision Analysis for the Development of the Italian Minor Airport System

The infrastructures supporting air transport throughout the world in the civil sector are classified as primary-level (large numbers of passengers and goods on both commercial and charter long- and medium-haul flights) and secondary-level (few passengers and goods on general aviation private, short-haul flights). In parallel with primary-level air traffic general growth all over the world and in Italy, the popularity of “individual” nonscheduled general aviation traffic increased in many countries since 1990s. The latter aviation has proved to be a valid alternative to rail and road transport for short-medium distance journeys (100-500 km) for classes of business and tourist passengers. In keeping with the national and international airport system development scenarios, the paper illustrates the results of in-depth analyses aiming to construct an integrated GIS-based Multicriteria Decision Analysis evaluation methodology. It gears towards formulating strategies for the development and streamlining of some existing (51) Italian minor airports and for the right locations for the new hubs required to construct an efficient second-level air transport network (the “highway in the sky”). Different levels of evaluation verify the suitability of airport services and infrastructure (status quo) and the attractiveness of airport hubs given the territorial facilities found in their catchment areas.

AHP-based evaluation of the karst collapse susceptibility in Tailai Basin, Shandong Province, China

Karst sinkholes began to appear in Tailai Basin of China in the 1970s and have been increasingly exacerbating ever since. Evaluation of the sinkhole susceptibility has been challenging. The lithology (Li), distance to fault (DF), overburden type (OTy), overburden structure (OS), overburden thickness (OTh), groundwater depth (GD), relative location between the groundwater table and bedrock (RL), pumping wells (PW) are chosen as conditioning factors. The weights of the factors are obtained based the analytic hierarchy process (AHP). Further, a GIS-based evaluation of the karst sinkholes susceptibility in the Tailai Basin is made. The Tailai Basin is divided into extremely susceptible area, highly susceptible area, moderately susceptible area and weakly susceptible area, and their corresponding areas are 60.15, 85.80, 61.69 and 19.88 km2, respectively. The extremely and highly susceptible areas are mainly distributed in Taian City and encompass an area of 145.95 km2. Results of this study provide a decision basis for prevention and treatment of karst sinkholes in the Tailai Basin.

GIS-based evaluation of diagnostic areas in landslide susceptibility analysis of Bahluieț River Basin (Moldavian Plateau, NE Romania). Are Neolithic sites in danger?

Abstract The aim of this study is to compare the predictive strenghtness of different diagnostic areas in determining landslide susceptibility using frequency ratio (FR), statistical index (SI), and analytic hierarchy process (AHP) models in a catchment from the northeastern part of Romania. Scarps (point), landslide areas (polygon), and middle of the landslide (point) have been tested and checked in regards to their performance. The three statistical models have been employed to assess the landslide susceptibility using eleven conditioning factors (slope angle, elevation, curvature, lithology, precipitations, land use, topographic wetness index (TWI), landforms, aspect, plan curvature and distance to river). The three models were validated using the receiver operating characteristic (ROC) curves and the seed cell area index (SCAI) methods. The predictive capability of each model was established from the area under the curve (AUC), for FR, SI and AHP; the values are 0.75, 0.81 and 0.78 (using polygon as diagnostic area), respectively. Among the three methods used, SI had a better predictability. When it comes to the predictability values regarding the diagnostic areas, the landslide area (polygon) proves to have the highest values. This results from the entire surface of the landslide being taken into account when validating the data. Approximately 70% of the Neolithic sites are located in areas with high and very high susceptibility to landslides, meaning that they are in danger of being destroyed in the future. The final susceptibility maps are useful in hazard mitigation, risk reduction, a sustainable land use planning, evaluation of cultural heritage integrity, and to highlight the most endangered sites that are likely to be destroyed in the future.

Water Quality Indices and GIS-based evaluation of a decadal groundwater quality

The water quality data of fixed 44 wells were monitored during post- and pre-monsoon season 2005–2013 of Kanchipuram district of state Tamil Nadu, India. Water Quality Indices (WQIs) methodology was applied to categorize groundwater on the basis of rating. In total, 13 groundwater quality parameters: calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), bicarbonate (HCO3−), nitrate (NO3−), chloride (Cl−), fluoride (F−), sulphate (SO42−), total hardness (TH), total dissolved solids (TDS), hydrogen ion concentration (pH) and electrical conductivity (EC) were taken for statistical analysis. Three different WQI models were computed using a decadal physicochemical water quality data mainly for drinking (WQI1 and WQI2) and irrigation (WQI3) need. The WQIs variability thematic maps were generated in the Geographical Information System environment through ArcGIS software. These spatial distribution maps of WQI provide a detailed overview. The work outlined that the groundwater of the area is impaired by the anthropogenic activities and needs proper management plan to control further contamination and pollution of the groundwater of the area. Further, the groundwater of few monitoring wells needs a proper treatment before its consumptive uses. The alternative water supply should be provided to local inhabitants for daily uses.

A GIS-based evaluation method of underground space resources for urban spatial planning: Part 2 application

Abstract Urban underground space (UUS) has been playing an important role in the urban development in recent years. The evaluation for its potential becomes essential for urban spatial planning. Previous research emphasized the fundamental data, while this paper not only emphasized the data provided by related departments, but also took into consideration the gap and relation between UUS and urban spatial planning. To provide theoretical support for urban spatial planning, this paper studied a method for evaluating UUS. In this method, an index system for UUS resource evaluation was put forward and its analytical process was based on the Geographic Information System (GIS) and some mathematical tools, such as the analytic hierarchy process (AHP), the most unfavorable grading method (MUGM) and the exclusive method (EM). Then this method was applied to UUS Master Plans and Detailed Regulatory Planning in Chinese cities, and proved to be relatively practicable. The research outcomes are presented in the form of two papers, each with a different focus. Part 1 aims to introduce the evaluation methodology, including construction suitability evaluation & potential value evaluation & volume estimation. Part 2 reports on applications of the method to Chinese cities of Tongren and Changzhou. Part 2 demonstrated the UUS resource evaluation methodology for Tongren city and Changzhou city in China. In Tongren, the UUS construction suitability and resource’s comprehensive quality (RCQ) evaluation was implemented on an urban scale. Firstly, factors influencing the potential for UUS, including the area’s landforms, engineering geology, hydrogeology, site stability, existing subsurface construction conditions, urban location, and land use were collected and analyzed based on GIS. Furthermore, a combination of AHP, MUGM and EM techniques were used in the analysis. Then the UUS construction suitability and RCQ distribution were got. The UUS layout structure was finally obtained based on RCQ distribution figure. Meanwhile, this case study shows that the area used for UUS accounts for only 2% of the effective utilization area of the whole city based on the volume estimation model. While for Changzhou, existing construction evaluation at the parcel scale was implemented for one downtown area. A “four steps” method was proposed to calculate the influence depth of building foundations based on the geographical statistical analysis module of GIS with an interpolation method. Flexible application of the method, with the addition of local project experience, can make the planners definitely determine which part of the area can be exploited. A flow chart of existing construction evaluation is finally presented.

A GIS-Based Evaluation of Environmental Sensitivity for an Urban Expressway in Shenzhen, China

Abstract Urban eco-environmental degradation is becoming inevitable due to the extensive urbanization, population growth, and socioeconomic development in China. One of the traffic arteries in Shenzhen is an urban expressway that is under construction and that runs across environmentally sensitive areas (ESAs). The environmental pollution from urban expressways is critical, due to the characteristics of expressways such as high runoff coefficients, considerable contaminant accumulation, and complex pollutant ingredients. ESAs are vulnerable to anthropogenic disturbances and hence should be given special attention. In order to evaluate the environmental sensitivity along this urban expressway and minimize the influences of the ongoing road construction and future operation on the surrounding ecosystem, the environmental sensitivity of the relevant area was evaluated based on the application of a geographic information system (GIS). A final ESA map was classified into four environmental sensitivity levels; this classification indicates that a large proportion of the expressway passes through areas of high sensitivity, representing 11.93 km or 52.3% of the total expressway, and more than 90% of the total expressway passes through ESAs. This study provides beneficial information for optimal layout schemes of initial rainfall runoff treatment facilities developed from low-impact development (LID) techniques in order to minimize the impact of polluted road runoff on the surrounding ecological environment.

A GIS-based evaluation method of underground space resources for urban spatial planning: Part 1 methodology

Abstract Urban underground space (UUS) has been playing an important role in the urban development in recent years. The evaluation for its potential becomes essential for urban spatial planning. Previous research emphasized the fundamental data, while this paper not only emphasized the data provided by related departments, but also took into consideration the gap and relation between UUS and urban spatial planning. To provide theoretical support for urban spatial planning, this paper studied a method for evaluating UUS. In this method, an index system for UUS resource evaluation was put forward and its analytical process was based on the Geographic Information System (GIS) and some mathematical tools, such as the analytic hierarchy process (AHP), the most unfavorable grading method (MUGM) and the exclusive method (EM). Then this method was applied to UUS Master Plans and Detailed Regulatory Planning in Chinese cities, and proved to be relatively practicable. The research outcomes are presented in the form of two papers, each with a different focus. Part 1 aims to introduce the evaluation methodology, including construction suitability evaluation & potential value evaluation & volume estimation. Part 2 reports on applications of the method to Chinese cities of Tongren and Changzhou. Part 1 analyzed the concept behind and the process involved in the UUS spatial planning evaluation methodology, combining construction suitability evaluation & potential value evaluation & volume estimation. Based on the factors that influence the development and utilization of a UUS, an index system for UUS resource evaluation is presented. Its primary components are construction suitability (including landform, geology, hydrogeology and the existing construction situation) and potential value (including urban spatial location and land use function). Using AHP, MUGM and EM, the level of each index was quantified and overlaid based on GIS, and then the UUS evaluation output was obtained, such as construction suitability distribution, Resource’s comprehensive quality (RCQ) distribution, with manifestation styles of maps and tables. In this research, three models are proposed, including a construction suitability model, a comprehensive quality model and a volume estimation model. The construction suitability model can evaluate the construction difficulty or cost grade, while the comprehensive quality model can evaluate potential benefit grade of every part in the city. They reflect the formula “Quality = Potential − Cost” to some extent. On the other hand, the volume estimation model can calculate the urban indicators for UUS, which can give data support for urban spatial planning.

GIS-based evaluation of groundwater geochemistry and statistical determination of the fate of contaminants in shallow aquifers from different functional areas of Agra city, India: levels and spatial distributions.

The quality of groundwater is very important in Agra because groundwater is the main source of water for drinking, domestic, agricultural and industrial uses. A groundwater geochemistry study was conducted in Agra where 28 samples were collected from shallow aquifers in May 2016 from different sites. The aim of this research was to assess the quality of groundwater for drinking purposes in the study area. Arc-GIS has been used to prepare geographic information system-based spatial distribution maps of different major elements. The groundwater quality was analyzed for various physico-chemical parameters, major cations and anions and some trace metals. The observed values were compared with BIS and WHO standards. Statistical parameters such as the mean, median, standard deviation, skewness and kurtosis were used to analyze the hydrogeochemical characteristics of the groundwater. Correlation coefficient analysis and principal component analysis (PCA) were performed to identify the sources of the water constituents. Our results showed that most of the samples exceeded the acceptable limit for drinking water standards. The sequence of abundance of the main cations was generally Na+ > Ca2+ > Mg2+ > K+, while the anions in order of abundance were HCO3− > Cl− > SO42− and NO3− > F−. All of the trace metals were within the permissible limit except for iron and manganese. The hazard index value of 5.7 × 10−2 indicated that there was no potential health risk in the study area. Ca2+, Mg2+, Cl− and SO42− were the dominant hydrogeochemical facies in the majority of the groundwater samples. Most of the parameters such as TDS, Cl−, HCO3−, SO42−, NO3−, Ca2+, Mg2+, Na+, K+ and TH showed strong correlations with each other, which were due to natural processes such as weathering, exchangeable ions and reduction/oxidation, as well as anthropogenic activity around the study area. The water quality index indicated that the water quality was poor at 46.43% of the sampling sites, very poor at 28.57% of the sites and unsuitable for drinking purposes at 25% of the sampling sites. Gibbs diagrams suggested rock weathering as a major driving force for controlling the groundwater chemistry in the study area, along with evaporation as a minor influence.

GIS-Based Evaluation of Spatial Interactions by Geographic Disproportionality of Industrial Diversity

Diversity of regional industry is regarded as a key factor for regional development, as it has a positive relationship with economic stability, which attracts population. This paper focuses on how the spatial imbalance of industrial diversity contributes to the population change caused by inter-regional migration. This paper introduces a spatial interaction model for the Geographic Information System (GIS)-based simulation of the spatial interactions to evaluate the demographic attraction force. The proposed model adopts the notions of gravity, entropy, and virtual work. An industrial classification by profit level is introduced and its diversity is quantified with the entropy of information theory. The introduced model is applied to the cases of 207 regions in South Korea. Spatial interactions are simulated with an optimized model and their resultant forces, the demographic attraction forces, are compared with observed net migration for verification. The results show that the evaluated attraction forces from industrial diversity have a very significant, positive, and moderate relationship with net migration, while other conventional factors of industry, population, economy, and the job market do not. This paper concludes that the geographical quality of industrial diversity has positive and significant effects on population change by migration.

Impact of geology and geomorphology on fluoride contaminated groundwater in hard rock terrain of India using geoinformatics approach

The present study demonstrates a GIS-based spatial evaluation of fluoride contamination (FC) in groundwater vis-a-vis geology and geomorphology of the area using analytical hierarchy process and weighted sum method in Palamu district of Jharkhand. The integration and analyses of the various thematic databases along with the field sampled fluoride data proved useful in delineating the FC zones. The FC index ranged between 141 and 707, and was classified into four zones, viz., low, moderate, high, and very high zones of FC. The FC index map showed that a total of 49.75% of the study area lies between high to very high FC zone. The very high FC zone is found in the moderately weathered plateau with granitic terrain, whereas the high and moderately FC zones covering 49.31 and 36.41% of the study area are dominated by plateau weathered shallow, pediment–inselberg complex, pediplain moderately weathered, pediplain shallow weathered, and inselberg which have high fluoride. The lowest FC zone covers an area of 193.27 sq. km (13.84%). The spatial analysis of geology with fluoride showed that groundwater within granitic gneiss exhibits high FC followed by granitoid gneiss and alluvium. Geomorphologically highest FC was recorded in plateau weathered moderate (91.67%) followed by plateau weathered shallow (71.43%), flood plain (41.76%), inselberg (27.27%), and pediment (25%). The spatial analysis of groundwater yield with fluoride showed that regions having good yield exhibit maximum FC thereby accelerating the vulnerability of the population to fluorosis.

GIS-based evaluation of groundwater quality and estimation of soil salinization and land degradation risks in an arid Mediterranean site (SW Tunisia)

Southwestern Tunisia is known for its high-quality date palm production. The agricultural activity supports the social and economic pressure. Considering prolonged drought conditions and surface water insufficiency, increasing supplies rely on deep aquifers in spite of the critical status of the water quality used. Intense agriculture development has placed oases durability and crop quality to high risks of soil fertility loss, land degradation, and water availability issues, due to severe climate conditions, overexploitation of groundwater resources, intense desertification, overuse of soil, and poor land management. The recent contamination of the largest aquifer in southern Tunisia (Continental Intercalaire) by petroleum flows adds another dimension to the problem of water crisis and soil salinization in the region of interest. In this study, 41 water samples from CI wells were correspondingly collected for hydrochemical analyses. Major and minor element concentrations were evaluated by different standard methods. The obtained dataset indicates that the western side possesses low salinity hazard, whereas Nefzaoua and El Fedjej areas reveal highly mineralized water unsuitable for irrigation purposes. A number of assessment ratios (KR, TH, SAR, ESP, PS, etc.) and graphical methods (Riverside and Wilcox) confirm this classification. The combination of geochemical indicators with geographic information system permits the assessment of water quality on the basis of two different indexes. The resulted maps show, in turn, scattered classification between the western field with acceptable water quality and El Fedjej-Nefzaoua areas where the CI water is unsuitable for agricultural activities. Besides water chemistry evaluation, the assessment of soil composition, particularly toxic element concentrations, constitutes reliable criteria for monitoring the effectiveness of agricultural practices and the suitability of irrigation water. Hence, the concentrations of four heavy metals have been monitored along three soil profiles ranging from the surface to 80 cm of depth. The results are within permissible limits. The vertical distribution of Ni, Pb, Cu, and Zn is related mainly to physiochemical soil parameters, difference in moisture, and fine fraction distribution.

Frequency ratio and GIS-based evaluation of landslide susceptibility applied to cultural heritage assessment

Abstract This study aims to produce landslide susceptibility maps using frequency ratio (FR) model with the help of GIS to be used in cultural heritage (CH) mitigation and assessment for a catchment from northeastern Romania. In total, seven conditioning factors were used to assess the landslide susceptibility index (LSI): elevation, slope angle, curvature, normalised difference vegetation index (NDVI), roughness, distance to rivers and landforms. The landslide susceptibility maps were prepared with the help of GIS software and classified into four susceptibility areas: low, medium, high, and very high. The more conditioning factors were added to the susceptibility, the better validation results were obtained (from an AUC = 0.51 corresponding for five factors, to an AUC = 0.75 for the seven factors). The model validation has shown that the maps made using FR model has a success rate of 75.24%. The landslide susceptibility maps have a high accuracy and will be helpful not only for CH protection and preservation, also for land-use planning, hazard mitigation, and risk reduction. Out of the 47 CH sites, more than a half are located in areas with high and very high susceptibility to landslides.