Flood susceptibility mapping using a geomorphometric approach in South Australian basins

Natural Hazards - Watershed characteristics and their hydrological responses can have severe effects on the occurrence and extent of floods. Therefore, this study focuses on the integration of...     

Perceived and actual risks of drought: household and expert views from the lower Teesta River Basin of northern Bangladesh

Natural Hazards - Disaster risk perception and risk appraisal are essential in formulating an appropriate disaster risk reduction policy. This study examines the actual vs perceived drought risks...     

Food security and dietary diversity of tea workers of two tea gardens in greater Sylhet district of Bangladesh

The study analyzed the food security and dietary diversity of tea workers in Lakkatura Tea Garden and Ootterbhag Tea garden in greater Sylhet district of Bangladesh. A total of 200 respondents (100 from each tea estate) were interviewed to evaluate the food security and dietary diversity. The study found that average daily per capita calorie intake by tea workers was 2095.96 kcal. In addition, around 85.30% of the total calorie intake was received from the rice consumption. Average per capita daily intake of rice was estimated at 538.51 gm which is higher than the national average. It was also observed that 71.7 and 65.0% households were food secure in Lakkatura and Ootterbhag Tea garden, respectively. In Lakkatura Tea Garden, 61.67% tea workers have medium dietary diversity and in Ootterbhag Tea Estate 49.47% tea workers have low dietary diversity. Using the logit model analysis, this study provides food consumption patterns of tea workers and determine the factors responsible for food security. Household size, farm income and daily calorie intake were found having significant influence on households’ food security. For improving socioeconomic conditions of tea workers, educational institution should be set up to improve their educational status and government should give loans for them at a low interest rate and create alternative job opportunity in off season.

     

Implementation of a Petrographical and Petrophysical Workflow Protocol for Studying the Impact of Heterogeneity on the Rock Typing and Reservoir Quality of Reefal Limestone: A Case Study on the Nullipore Carbonates in the Gulf of Suez

This study focuses on the heterogeneity of the middle Miocene syn-rift Belayim nullipore (reefal) marine sequences in the Gulf of Suez and its impacts on reservoir quality. The sequences consist of coralline algal reef limestones with a highly complex dual-porosity system of primary and secondary porosities of widely varying percentages. To achieve a precise mathematical modeling of these reservoir sequences, a workflow protocol was applied to separate these sequences into a number of hydraulic flow units (HFUs) and reservoir rock types (RRTs). This has been achieved by conducting a conventional core analysis on the nullipore marine sequence. To illustrate the heterogeneity of the nullipore reservoir, the Dykstra-Parsons coefficient (V) has been estimated (V = 0.91), indicating an extremely heterogeneous reservoir. A slight to high anisotropy (λk) has been assigned for the studied nullipore sequences. A stratigraphic modified Lorenz plot (SMLP) was applied to define the optimum number of HFUs and barriers/baffles in each of the studied wells. Integrating the permeability-porosity, reservoir quality index-normalized porosity index (RQI-NPI) and the RQI-flow zone indicator (RQI-FZI) plots, the discrete rock types (DRT) and the R35 techniques enable the discrimination of the reservoir sequences into 4 RRTs/HFUs. The RRT4 packstone samples are characterized by the best reservoir properties (moderate permeability anisotropy, with a good-to-fair reservoir quality index), whereas the RRT1 mudstone samples have the lowest flow and storage capacities, as well as the tightest reservoir quality.     

Rudists (Bivalvia) from a Cretaceous Platform in Northern Egypt:Taxonomy and Paleobiogeography

New well-preserved rudist materials come from the Barremian–Turonian marine formations in the Yelleg, Minsherah, Maaza, and Raghawi sections in North Sinai, northern Egypt. There, 17 discovered rudist species belonging to 13 genera and seven taxonomic families are described in detail as follows: Eoradiolites plicatus (Conrad), Eoradiolites liratus (Conrad), Praeradiolites ponsianus (?Archiac), Archaeoradiolites sp., Bournonia africana Douvillé, Bournonia fourtaui Douvillé, Biradiolites lombricalis (?Orbigny), Biradiolites zumoffeni Douvillé, Radiolites lewyi lewyi Parnes, Radiolites sauvagesi (?Hombres-Firmas), Durania arnaudi (Choffat), Toucasia carinata (Matheron), Toucasia sp., Neocaprina raghawiensis Steuber and Bachmann, Sellaea sp., Ichthyosarcolites sp. and Horoiopleura sp.. The Cenomanian deposits in the northern Eastern desert of Egypt only contain E. liratus. The domination of the Cenomanian rudist species in North Sinai, however, is attributed to changes in the platform, which passes mainly from carbonate in the north to siliciclastics in the south. The presence of Horiopleura sp. in the late Barremian–early Aptian deposits is documented for the first time, which suggests the expansion of taxa of the genus Horiopleura Douvillé to North Sinai during this interval. The age of the rudist species is documented from the late Barremian–Turonian formations, with their geographic distribution in the Mediterranean region considered..     

Landslide susceptibility mapping using machine learning algorithms and comparison of their performance at Abha Basin,Asir Region,Saudi Arabia

The current study aimed at evaluating the capabilities of seven advanced machine learning techniques(MLTs),including,Support Vector Machine(SVM),Random Forest(RF),Multivariate Adaptive Regression Spline(MARS),Artificial Neural Network(ANN),Quadratic Discriminant Analysis(QDA),Linear Discriminant Analysis(LDA),and Naive Bayes(NB),for landslide susceptibility modeling and comparison of their performances.Coupling machine learning algorithms with spatial data types for landslide susceptibility mapping is a vitally important issue.This study was carried out using GIS and R open source software at Abha Basin,Asir Region,Saudi Arabia.First,a total of 243 landslide locations were identified at Abha Basin to prepare the landslide inventory map using different data sources.All the landslide areas were randomly separated into two groups with a ratio of 70%for training and 30%for validating purposes.Twelve landslide-variables were generated for landslide susceptibility modeling,which include altitude,lithology,distance to faults,normalized difference vegetation index(NDVI),landuse/landcover(LULC),distance to roads,slope angle,distance to streams,profile curvature,plan curvature,slope length(LS),and slope-aspect.The area under curve(AUC-ROC)approach has been applied to evaluate,validate,and compare the MLTs performance.The results indicated that AUC values for seven MLTs range from 89.0%for QDA to 95.1%for RF.Our findings showed that the RF(AUC=95.1%)and LDA(AUC=941.7%)have produced the best performances in comparison to other MLTs.The outcome of this study and the landslide susceptibility maps would be useful for environmental protection.     

Effects of land-cover and watershed protection futures on sustainable groundwater management in a heavily utilized aquifer in Hawai‘i (USA)

Hydrogeology Journal - Groundwater sustainability initiatives, including sustainable yield and watershed policy protection policies, are growing globally in response to increasing demand for...     

Adsorption of Lead (II) and Zinc (II) from Aqueous Solution by Bituminous coal

Activated carbons have been proven to be effective adsorbents for the removal of Pb (II) and Zn (II) dissolved in aqueous media. The study of adsorption of Pb (II) and Zn (II) on two different size fractions from a composite coal sample of Maghara coal mine, C₆₃ (63–125 μm) and C₂₅₀ (125–250 μm) is presented in this paper. C₆₃ and C₂₅₀ were treated in water solutions of 50 mM lead and zinc acetates. X-ray photoelectron spectroscopy (XPS) was used to characterize the starting and treated coal surfaces. The high surface area and surface functional groups (carboxy and phenolic) enable activated bituminous coal of Maghara to act as efficient adsorbents for removing dissolved Pb (II) and Zn (II) in alkaline medium.     

Precision assessment of the orthometric heights determination in northern part of Algeria by combining the GPS data and the local geoid model

The main purpose of this article is to discuss the use of GPS positioning together with a gravimetrically determined geoid, for deriving orthometric heights in the North of Algeria, for which a limited number of GPS stations with known orthometric heights are available, and to check, by the same opportunity, the possibility of substituting the classical spirit levelling. For this work, 247 GPS stations which are homogeneously distributed and collected from the international TYRGEONET project, as well as the local GPS/Levelling surveys, have been used. The GPS/Levelling geoidal heights are obtained by connecting the points to the levelling network while gravimetric geoidal heights were interpolated from the geoid model computed by the Geodetic Laboratory of the National Centre of Spatial Techniques from gravity data supplied by BGI. However, and in order to minimise the discordances, systematic errors and datum inconsistencies between the available height data sets, we have tested two parametric models of corrector surface: a four parameter transformation and a third polynomial model are used to find the adequate functional representation of the correction that should be applied to the gravimetric geoid. The comparisons based on these GPS campaigns prove that a good fit between the geoid model and GPS/levelling data has been reached when the third order polynomial was used as corrector surface and that the orthometric heights can be deducted from GPS observations with an accuracy acceptable for the low order levelling network densification. In addition, the adopted methodology has been also applied for the altimetric auscultation of a storage reservoir situated at 40 km from the town of Oran. The comparison between the computed orthometric heights and observed ones allowed us to affirm that the alternative of levelling by GPS is attractive for this auscultation.