Low Potential Zones Research Articles

Delineating potential sites for artificial groundwater recharge using a mathematical approach to remote sensing and GIS techniques

Abstract The management of available groundwater resources is vital in arid and semi-arid regions. Artificial recharging should be integrated with groundwater resources to maintain long-term water sustainability. This study applied the cost-effective and time-saving techniques of remote sensing and GIS to delineate the groundwater recharge potential in the Al-Sarhan Basin, located in arid and semiarid regions of Jordan, by following the weighted linear combination method. The results revealed three distinct groundwater potential recharge zones (low, moderate, and high potential zones). High to moderate groundwater recharge potential zones occupied 75% of the Al-Sarhan area with considerable artificial recharge capacity because of the suitable geology, soil texture, drainage density, and flat terrain conditions. The maps produced also depicted that 25% of the Al-Sarhan area possesses low groundwater recharging potential. The model further revealed that 93% of the wells in the study area were located in potential groundwater recharge zones.

Hydrogeochemistry of karst groundwater for the environmental and health risk assessment: The case of the suburban area of Chongqing (Southwest China)

Karst groundwater is a vital resource for drinking, living and irrigation purposes in karst agricultural areas of the world. Due to the vulnerability of karst aquifers, surface pollutants are easily transferred to the subsurface and make karst groundwater be deteriorated, thereby restricting the rational exploitation of karst groundwater resource. In view of this, 49 karst groundwater samples were collected from spring (SW) and underground river (URW) sites in the suburban area of Chongqing City and analyzed for various hydrochemical components. Particularly, the karst groundwater quality was comprehensively uncovered by combining characteristics of hydrogeochemical evolution and health risks caused by nitrate and fluoride. The results revealed that the karst groundwater was slightly alkaline in nature and the water types were mainly characterized by Ca-HCO3 accounting for 93.88% of the total samples due to the heavy dissolution of carbonate rock. The relatively high concentrations of Na+, SO42− and NO3− up to 271.88 mg/L, 277.94 mg/L and 56.94 mg/L were over the corresponding maximum acceptable limits for drinking water, which can be predominately attributed to the emissions of industrial park, dissolution of gypsum and pyrite and excessive application of chemical fertilizers. Although agricultural activities were stopped and chemical fertilizers were no longer applied during the sampling period, long-term application of fertilizers have a persistent adverse effect on the karst groundwater NO3−. The pollution index of the karst groundwater (PIG) revealed that the low pollution and potential pollution zones were noticed in the northwestern parts of the study area. With respect of the SW, all the total hazard index (HI) values were below 1 suggesting no significant health risk. On the contrary, HI values of 0.11–1.16 for adults, 0.15–1.61 for children and 0.17–1.83 for infants in the URW indicated significant noncarcinogenic health risks. Particularly, infants and children were more vulnerable to karst groundwater NO3− than adults. Furthermore, the noncarcinogenic health risks of karst groundwater can be mainly attributed to NO3−, confirmed by the higher contribution ratio (66.55%) to the HI values. Therefore, special and targeted measures need to be taken to decrease the NO3− concentration in agricultural area.

Applications of geospatial analysis and analytical hierarchy process to identify the groundwater recharge potential zones and suitable recharge structures in the Ajani-Jhiri watershed of north Maharashtra, India

The present study undertakes the integration of hydrogeological, geospatial and multi-criteria decision analysis (MCDA) techniques to identify groundwater recharge potential zones and suitable recharge structures in parts of the Ajani-Jhiri watershed of the Tapi river basin, north Maharashtra, India. Hydrogeological thematic layers include drainage density, lineament density, geology, geomorphology, land use/landcover, soil and slope, which are the demarcating factors in identification of potential recharge sites of the watershed. An analytical hierarchy process model based on MCDA methodologies was adapted to determine the overall weightage distribution for individual layers for weighted overlay to be executed in GIS environment. Groundwater recharges potential zones are divided into high, moderate, and low classes. Results showed that only 272.72 km2 (38.02%) area has high recharge potential, while 316.94 km2 (44.07%) has moderate groundwater recharge potential. The low groundwater potential recharge zone (129.35 km2; 17.98%) is located in the southern part of the watershed, which is mountainous terrain. Locations of new recharge structures, including six stream bunds, five check dams and two percolation tanks are recommended to meet the regional domestic and agricultural needs. The water bodies in the region are partially silted with loose materials, hence three desiltation tanks proposed.

Smallholders' coping strategies in response to climate variability in semi-arid agro-ecozones of Upper Eastern Kenya

Rainfed agriculture dominates food production systems in arid and semi-arid agro-ecozones. Water is a key limiting factor to crop growth in the small-scale farming systems of the Sub-Saharan Africa (SSA) region. Climate adaptation is a fundamental and necessary response to the threat posed by the current and future climatic changes in semi-arid farming systems of the SSA region. This study was implemented to identify the socioeconomic drivers and determinants of adaptation to rainfall variability at the farm level in contrasting agro-ecological zones of Kenya. Two hundred and seventy (270) farmers were selected. The survey was implemented in Mbeere South, Meru South, and Maara Sub-Counties in Kenya to determine farmers' perceptions of climate variation during the decade that preceded the survey and climate adaptation strategies that farmers implemented. The most common climate adaptation strategies included the use of terraces (89%), early maturity crop varieties (82%), and intercropping (79%). In comparison, the least common strategies included water-harvesting strategies (29%), trenches (35%), and staggering planting dates (46%). Farmers in low potential agro-ecological zones recorded lower education levels, less secure land tenure systems, and poor access to training, extension, and credit facilities necessary for successful climatic adaptation strategies. The study findings indicated that farmers in low potential zones, including Mbeere South Sub-County, faced more risks due to the nature of climatic variation in this agro-ecozone. Farm socioeconomic characteristics were important factors that influenced farmer adaptation, including gender and age differentials, education attainments and agricultural training, farm labor availability, household food security status, and preceding annual occurrences of crop failure. There is a need to develop holistic approaches that incorporate scientific findings from the researchers and the local household-based strategies that can enhance risk assessment and management, coping and adaption strategies, and decision-making by multiple stakeholders.

A GIS-Agriflux Modeling and AHP Techniques for Groundwater Potential Zones Mapping

Groundwater is considered as the main portion of the water supply in arid and semi-arid regions. The Sfax plain area is part of the arid/semi-arid areas of Tunisia that are subject to the impact of climatic and human pressures. Water scarcity in combination with groundwater exploitation is a major concern in this region. Therefore, sustainable management and protection of groundwater resources, it necessary. The delineation of groundwater potential (GP) zones becomes an increasingly important tool for implementing successful management programs. The purpose of the present paper is to assess the potential zone of groundwater resources in the study area. An efficient approach using geographical information system (GIS), hydrological modelling and analytical hierarchy process (AHP) was developed. At first, six groundwater parameters that affect groundwater occurrences are derived from the spatial geodatabase. Those parameters are: Infiltration rate estimated from a GIS linked model, lineament density, drainage density, slope, rainfall and Land use/land cover. Then, the assigned weights of thematic layers based on expert knowledge were normalized by eigenvector technique of AHP. The parameter layers were integrated and modeled using a weighted linear combination (WLC). The resulting map was classified into four categories: very low, low, good, and excellent. The results showed that about 26% of the study area falls under very-low-potential zone, with 30% on low-potential zone, 21% with good potential zone, and 23% falling under excellent zone. The results of the analysis were validated using pumping rate data and curve trend of sensitivity classes theory validation of outcomes indicated a good prediction accuracy. The results of the present study can serve to prepare a comprehensive groundwater development and management plans proving its efficacy in this art of exploratory investigations.

Application of analytical hierarchy process and integrated fuzzy-analytical hierarchy process for mapping potential groundwater recharge zone using GIS in the arid areas of Ewaso Ng'iro – Lagh Dera Basin, Kenya

The demand for freshwater has continuously increased in the arid areas of Ewaso Ng'iro – Lagh Dera basin, Kenya. This study aimed to and mapped areas of potential groundwater recharge in the basin by integrating factors that influence groundwater recharge using Analytical Hierarchical Process, and Fuzzy-Analytical Hierarchical Process in ArcGIS. The results of this study are presented in form of maps indicating the potential groundwater recharge zones. The zones are categorized as high, medium and low potential groundwater recharge zone, which were validated with the location of the fresh water boreholes. High groundwater recharge potential zones occur in the central part of the study area within the generally flat flood plains consisting of alluvium lithology. In contrast, low potential groundwater recharge zones occur in the southwestern part of the area within upland plains. The study can be helpful in the proper management of the groundwater resource.

Farm factors influencing soil fertility management patterns in Upper Eastern Kenya

Farmer adoption of soil technologies has been commonly explored in the literature using binary models, which significantly simplifies the multi-dimensional nature of soil technology adoption. Therefore, it is necessary to fill this gap to improve technology adoption models to enhance small-scale farmers' soil fertility management practices. We investigated patterns of multiple soil technology adoption using multivariate analysis and regression modeling in Central Kenya. We used a cross-sectional survey design to sample 300 small-scale farmers in Tharaka-Nithi County and employed a multi-stage sampling design. We found that soil nutrient applications and soil fertility management patterns were linked to crop enterprises, driven by socioeconomic farm characteristics. Our findings showed that farmers applied higher N inputs and soil fertility management technologies on crops with high economic and staple use-values. Farmers in high potential agro-ecozones and those with higher incomes and TLU (Tropical Livestock Units) intensity applied higher fertilizer N intensities than farmers in low-potential zones, with lower incomes and lesser TLU intensities. Farm size was inversely related to nitrogen application intensity, while farmers had a lower propensity to restore fields undergoing degradation. We obtained five significant sets of soil fertility management technologies that farmers practiced due to the complementary nature of their benefits. We found that farmer perceptions of soil fertility, income distribution, site, education qualifications, credit access, labor availability, and access to extension services influenced their technology adoption patterns. We recommend that farmer sensitization about the fertility of their soils is needed to enhance soil fertility management strategies in small-scale farming systems.

A novel ensemble model of automatic multilayer perceptron, random forest, and ZeroR for groundwater potential mapping.

Declining levels of the water table in India have become a major concern, especially with climate change and burgeoning population compounding the problem and causing a perpetual state of water crisis. A better insight into the state of these precious resources is essential for their planned exploration and usage. This study introduces a novel machine learning ensemble model (ARZ ensemble), through an implementation of majority voting-based technique over its standalone classifier constituents, namely, Automatic Multilayer Perceptron (AutoMLP), random forest (RF), and ZeroR for undertaking the groundwater potential mapping for the Jabalpur district, Madhya Pradesh. Ten groundwater influencing factors (i.e., slope, rainfall, aspect, elevation, topographic wetness index, land use, lithology, distance from rivers, plan and profile curvature) and groundwater well locations from the study area were used to construct the spatial database. In order to validate the applicability of the proposed model, its performance was compared against a conventionally employed statistical method of Shannon's entropy (SE) model. The results revealed that the ARZ ensemble model (AUC: 0.8542) outperformed SE (AUC: 0.7639). The groundwater potential map revealed that approximately 4.18% of the region has very high groundwater potential, while 47.66% belongs to a low potential zone. Such information can hold solutions for a lot of the ailments afflicting these resources and can genuinely aid in the attempts to restore them to their natural state.

Delineation of Groundwater Potential Zones (GWPZ) of Port Blair, Andaman Islands, India, using Multi Influencing Factors (MIF) method and geospatial techniques

This study intended to delineate the groundwater potential zones (GWPZ) of Port Blair and its surrounding areas using the Multi Influencing Factor (MIF) method and geospatial techniques. Multiple data such as geology, geomorphology, slope, soil, drainage density, lineament density, rainfall, NDVI, and LULC were considered for delineating GWPZ. Spatially distributed maps/thematic layers of all the factors mentioned above were prepared using remotely sensed data and by using ground data. These thematic layers were allotted weights after referring to previous literature and study and by considering each layer's influence on groundwater. Finally, all the thematic layers were integrated, and overlay analysis was done to produce a map showing the GWPZ of Port Blair and its surrounding areas. The result (map) was categorized into high, medium, and low groundwater potential zones. This study shows that most of Port Blair's areas come under the medium GWPZ (63.4% of the study area), followed by high GWPZ (27% of the study area), and 10.6% of the area comes under low GWPZ. The most important and innovative part of this study is the physical verification of all the results obtained from the remote sensing and GIS techniques. The GWPZ map was compared with existing well discharge data and validated through the ROC curve, and it shows the study has “very good” accuracy. Finally, this study provides an expedient approach to delineate the GWPZ for practicable management and use of groundwater resources of the area to maintain the sustainability of this island.

Mineralisation potential assessment using analytical hierarchy process (AHP) modeling technique: A case study of Ilesha schist belt, southwestern Nigeria

A mineralisation potential assessment in part of Ilesha Schist belt of southwestern Nigeria was carried out using multi criteria decision analysis (MCDA) in the context of analytical hierarchy process (AHP). Three parameters sourced from aeromagnetic, electrical resistivity and geological data were identified to favour gold mineralisation in the study area. These parameters include lineament density (Ld), lithology (Lt), and electrically derived coefficient of anisotropy (An). The application of data enhancement techniques such as total horizontal derivative, 3-D Euler deconvolution and source edge detection were employed in the production of lineament map of the study area. Two hundred and sixty-five (265) vertical electrical sounding (VES) points were investigated using Schlumberger configuration. Coefficient of anisotropy derived from the Dar-Zarouk parameters was obtained from the synthesized VES data. The lithologic information was obtained from the existing geological map of the area. The orientations of lineaments displayed on the aeromagnetic results suggest predominantly NE-SW trending structures, which are characteristic of the Pan African orogenic events in the area. However, few of the E-W trending lineaments are imprints of secondary structural alteration. Furthermore, the Euler deconvolution solutions revealed that the area is characterised by geological contacts with estimated depth of 94–600 m. The coefficient of anisotropy results obtained from the geo-electric parameters vary from 1.00–2.87. AHP weighting and ranking technique was used to develop a reliable mineralisation potential model (MPM). In line with the recommended lower limit of 10 %, the consistency ratio of the developed model is 9.61 %. The produced MPM was classified into low, moderate and high mineralisation potential zones. Preliminary validation of the MPM using the existing pits in the area showed 79 % success rate. The validation of the model using the existing geochemical information from the previous studies indicated 85 % agreement with the conceptual model; thus, confirming the reliability of the produced MPM. The developed model is therefore believed to serve as a future reference in the resource management of the study area.

Ecotourism Potential Zone Mapping by Using Analytic Hierarchy Process (AHP) and Weighted Linear Algorithm: A Study on West Bengal, India

This study was designed to demarcate the Ecotourism Potential Zones (ETPZs) of West Bengal using the Analytic Hierarchy Process (AHP) and weighted linear algorithm by considering three sustainable tourism parameters and sixteen indicators. Those three parameters are 1) physical (P), 2) social (S), and 3) availability of scenic beauty and infrastructures (ASI). Overall, 5 parameters are merged under physical (P), 2 parameters are integrated under social (S), and 9 parameters are incorporated under availability of scenic beauty and infrastructures (ASI). A 4-step procedure has been adopted for this study: 1) a simple hierarchical structure has been outlined, 2) pair-wise comparison matrices are formed, 3) weighted linear algorithm technique is utilized to get the ecotourism potentiality zone, and 4) ecotourism potentiality map is classified into high, moderate and low categories based on the principle of Dominant and Distinctive Function (DDF). As a result, about 61.65% area is identified with high ecotourism potential zone, 17.86% area is observed under the moderate ecotourism potential zone, and 20.48% area is recognized as the low ecotourism potential zone. Thus, the study considers an exceptional methodological framework that is applicable in any region of the world.

Effects of urbanisation in a shallow coastal aquifer: An integrated GIS-based case study in Cochin, India

Urbanisation impacts the availability and quality of renewable natural resources, particularly water resources. In coastal regions, the magnitude of urbanisation and its consequences is more prevalent. However, there are limited quantitative assessments on how urbanisation affects the groundwater system, especially the groundwater potential. Therefore, in the present study, we analysed the variability in groundwater potential zones due to the temporal changes in land use land cover (LULC) for Cochin, Kerala, India. For this, a GIS-based weighted overlay analysis method was performed with six geo-environmental factors to delineate groundwater potential zones (GWPZ). GWPZ at three different decadal time points from 1992 to 2019 was derived using the representative LULC maps. Our analysis showed a significant reduction in the high potential zone, decreasing from 75.34 % to 17.53 %. Contrastingly, the low potential zone rose from 0 to 11.8 % from 1992 to 2019. The temporal change in the spatial pattern in GWPZ named Groundwater Potential Change Index (GWPCI) was derived through pixel-level change detection. We performed a long-term (1985–2017) trend analysis on groundwater levels obtained for a network of twenty-three observation wells from the study area to validate the results. The trend analysis showed that 47 % of the wells display a statistically significant declining water level trend. Subsequently, twelve wells were selected to perform a bivariate statistical analysis between the long-term trend in water level and GWPCI. Ten wells showed a reasonable agreement to the negative change in GWPCI, while two displayed no relation to GWPCI. The study illustrates the effect of LULC change patterns in the groundwater system since significant alterations were observed on GWPZ. The systematic approach adopted in the present study can contribute to sustainable land and water resource management aimed at reducing the urbanisation impact on the groundwater system in the future.

Groundwater potential zone mapping of Hoshangabad and Budhni industrial area, Madhya Pradesh, India

Hoshangabad and Budhni industrial area is sub-humid part of the Narmada river basin, Madhya Pradesh, India. In the area, irrigation, domestic and industrial water supply relies on the available groundwater resources. The regular withdrawal of groundwater for irrigation, domestic and industrial use has results in lowering of groundwater table in the area. To overcome this problem potential recharge zones of groundwater were delineated in the area by applying remote sensing and GIS approach supported by field observations. GIS technology has been used to analyze and integrate various groundwater-controlling factors viz; Geology, Geomorphology, Lineaments, Topography, Soil, Drainage density and Land use/Land cover. Weightage to each parameter was assigned based on the hydrological characteristics of the observed parameter. Groundwater Potential Index (GPI) of the area has been calculated, by integration of the various thematic layers by Weighted Overlay Analysis (WOA) method in ArcGIS. The results demonstrated that about (3.58 km2) of the area is designated as excellent groundwater potential zone, whereas, good, moderate, low and poor groundwater potential zone covers (51.18 km2); (117.36 km2); (38.59 km2) and (6.66 km2) area respectively. The study reveals most effective groundwater potential zone lies in southernmost part of the area characterized by alluvium formations with gentle slope. Low and poor groundwater potential zone is present in the northernmost part characterized by steep slope, impervious rocks and high drainage density. Further, the results were validated by overlay the well inventory data of observation wells in the delineated potential recharge zones using GPS locations. The study has proved uneven distribution of these groundwater potential zones is controlled by the observed parameters. The study will be help in development and management of groundwater resources by enhancing the recharge practices, especially in poor and low groundwater potential zone.

Integrated remote sensing and GIS techniques to delineate groundwater potential area of Chamchamal basin, Sulaymaniyah, NE Iraq

Groundwater management in the semi-arid areas is a crucial issue and requires more scientific study and techniques. Groundwater potential areas for part of the Chamchamal basin are determined using two techniques, the analytical hierarchy process (AHP) and a geographic information system (GIS). Several Input factors were used to produce a thematic map, including geology, structure, drainage density, land-use/landcover, slope steepness, lineament density, and hydrogeology. Based on the relative importance, the layers are ranked which control the groundwater potential areas. The factor classified into several zones builds upon the hydrogeological characteristics and the classes weighted based on the relative standing to the potential area of groundwater. The output of the analysis showed that there are four zones of groundwater potential, good, moderate, poor, and very poor. The zones cover 10.4, 38.7, 43.93, and 6.96% of the area, respectively. Furthermore, the results showed that the southwest part of the area is the most favorable area for groundwater existence. While the center and some parts of the northeast characterized by low groundwater potential zones. To verify the final potential zones, the yield rates of 38 wells are used. The verification process verified that the categories of groundwater potential areas are closed to the results obtained from (AHP) and (GIS).

Identification of groundwater potential recharge zones using GIS-based multi-criteria decision analysis: A case study of semi-arid midlands Manyara fractured aquifer, North-Eastern Tanzania

The extraction of groundwater has recently increased due to water scarcity as a result of human activities including agriculture, industrial and domestic use. This has accelerated the need to spatially identify groundwater potential zones for artificial aquifer recharge and extraction through boreholes drilling. The current study is aimed at identifying groundwater potential recharge zones (GPRZ) of semi-arid midlands Manyara fractured aquifer using Geographic Information System (GIS) and Multi-criteria Decision Analysis (MCDA) based on Analytic Hierarchy Process (AHP) technique. The study area solely depends on groundwater for human survival through deep and shallow boreholes water extraction. Eight influencing factors including aquifer lithology, slopes, land use/land cover (LULC), soil types, drainage density, geological lineament density, flow accumulation, and topographic wetness index (TWI) were determined and reclassified on a scale of 1–5 in ArcGIS 10.6 environments. These factors were weighted with the help of AHP and integrated with ArcGIS pro based on the weighted linear combination (WLC) method. The results were scaled into five recharge potential classes; very high, high, moderate, low, and very low recharge potential zones. The results indicates that about 1607 km2 (14.7%) of the study area is under very high potential recharge zones, 3982 km2 (36.43%) falls under high recharge zones, 3120 km2 (28.55%) moderate, 1658 km2 (15.17%) low and 562 km2 (5.14%) under very low recharge zone. To assess the accuracy of the result a total of 66 boreholes collected from the field were used and the Receiver Operator Characteristics (ROC) curve generated. The area under the curve (AUC) was found to be 78% signifying moderate to higher accuracy of the model. The presented results provide an inventory of information for the land, water, environmental policy maker's authorities, and other stakeholders to enhancing groundwater resource management within semi-arid midlands Manyara basement fractured aquifer of the internal drainage basin North-Eastern Tanzania.

APG: A novel python-based ArcGIS toolbox to generate absence-datasets for geospatial studies

One important step in binary modeling of environmental problems is the generation of absence-datasets that are traditionally generated by random sampling and can undermine the quality of outputs. To solve this problem, this study develops the Absence Point Generation (APG) toolbox which is a Python-based ArcGIS toolbox for automated construction of absence-datasets for geospatial studies. The APG employs a frequency ratio analysis of four commonly used and important driving factors such as altitude, slope degree, topographic wetness index, and distance from rivers, and considers the presence locations buffer and density layers to define the low potential or susceptibility zones where absence-datasets are generated. To test the APG toolbox, we applied two benchmark algorithms of random forest (RF) and boosted regression trees (BRT) in a case study to investigate groundwater potential using three absence datasets i.e., the APG, random, and selection of absence samples (SAS) toolbox. The BRT-APG and RF-APG had the area under receiver operating curve (AUC) values of 0.947 and 0.942, while BRT and RF had weaker performances with the SAS and Random datasets. This effect resulted in AUC improvements for BRT and RF by 7.2, and 9.7% from the Random dataset, and AUC improvements for BRT and RF by 6.1, and 5.4% from the SAS dataset, respectively. The APG also impacted the importance of the input factors and the pattern of the groundwater potential maps, which proves the importance of absence points in environmental binary issues. The proposed APG toolbox could be easily applied in other environmental hazards such as landslides, floods, and gully erosion, and land subsidence.

Hydrogeophysical investigation for the aquifers in part of Ilorin, Central Nigeria: Implication on groundwater prospect

Hydrogeophysical study involving the use of Vertical Electrical Sounding (VES) was carried out in part of the basement complex rocks of Ilorin, central Nigeria, with the aim of determining its geoelectric parameters and groundwater potential. A total of thirty (30) VES were carried out using Schlumberger electrode configuration, with half electrode separation (AB/2) varying from 1m to 100m. Information on the subsurface lithologies, overburden thickness and aquiferous layers were obtained from the different VES locations in the study area. From the quantitative interpretations of the data collected, using the method of curve matching with the Orellana-Mooney master curves and 1-D forward modeling with WinResist 1.0 version software, three to five lithologic units were identified in the study. These include: the topsoil, sandy/lateritic clay/laterite, the weathered basement, the fractured basement and the fresh bedrock which are predominantly of the ‘KH’ curve type (30%), followed by ‘H’ type (26.7%), other type curves include ‘QH’ (16.7%), ‘HKH’, ‘HA’ and ‘A’ (6.7% each) and KQ and KQH (3.3% each). The weathered layer and the fractured basement constitute the main aquifer units. The aquifers are of generally low resistivity values (mostly below 100 Ω-m). The depths to dry bedrock at the chosen VES locations vary from 2.7 to 62.7 m with a mean value of 13.02 m in the study area. The geoelectrical interpretations of data obtained in these areas have permitted the delineation of the study area into low and moderate groundwater potential zones. This study is expected to assist in future planning for groundwater resources.
 Keywords: Hydrogeophysical, Basement Complex, Groundwater, Electrical Soundings, Weathered, Fractured

Geospatial mapping of groundwater potential zones using multi-criteria decision-making AHP approach in a hardrock basaltic terrain in India

Among all other natural resources, groundwater is one of the most essential for environmental, biological, and socioeconomic activities. Several factors such as geology, distance from the river, geomorphology, slope, land-use, drainage density, lineament density, soil, and rainfall influence groundwater recharge and its availability. In this study, an integrated approach of Geographical Information System (GIS) based Multi-Criteria Decision Making (MCDM), Analytical Hierarchy Process (AHP), and remote sensing were used for geospatial mapping of groundwater. For the determination of influencing factors, an extensive literature review was considered to form a pairwise comparison matrix (PCM) and calculate the weight of each factor. The scores of the sub-parameters were also assigned based on published literature, and after that, the weighted overlay analysis (WOA) tool in ArcGIS10.1 was used to produce the final groundwater potential map. About 14% (684 km2) of the study area is recognized as ‘high groundwater potential zone’, 34% (1591 km2) in ‘moderate groundwater potential zone’, 27% (1291 km2) in ‘low groundwater potential zone’ and the remaining 24% (1141 km2) in ‘poor groundwater potential zone’. In the accuracy assessment, the groundwater potential zones i.e. high, moderate, and poor in suitability map is precisely estimated contrasting to the zone ‘low’ in the producer’s point of view, but high and poor groundwater zones detected more precisely compared to others in user’s point of view. The methodology, techniques, and results of the current investigation may be useful to evaluate the groundwater potential zone in similar drought-prone regions around the world.

Insights into the corrosion mechanism and electrochemical properties of the rust layer evolution for weathering steel with various Cl− deposition in the simulated atmosphere

This study aims to make clear the effect of various Cl− deposition conditions on the changes of corrosion mechanism and electrochemical properties of the rust layer for weathering steel. The results indicate that the corrosion rate in presence of low Cl− deposition is divided into three stages: sharp increase stage, rapid decrease stage and tending to be stable stage. While, the high Cl− deposition process is divided into two stages: sharp increase stage and decrease stage. The increased of Cl− deposition increase the contents of the γ-FeOOH and β-FeOOH and decrease the contents of the α-FeOOH, and then to reduce the corrosion resistance. For the initial corrosion cycles, the increased of Cl− deposition influence the oxygen supply, resulting in spatial heterogeneity of the potential distribution to promote the corrosion reaction. As the prolonged corrosion cycles, the weathering steel of low Cl− deposition forms a protective rust layer to make the potential distribution become relatively uniform to reduce the corrosion rate, while the weathering steel of high Cl− deposition of the potential distribution is more unevenly distributed with distinct low and high potential zones to promote corrosion reaction.

Evaluating Agribusiness Regulatory Compliance among Vegetable Producers in Kenya Against Consumers’ Willingness to Pay for Food Safety

Purpose: For many years the failure of actors such as farmers to comply with regulations that promote public good, such as adherence to safe practices in the use of agrochemicals was only understood from a position of weak enforcement and surveillance. The study sought to evaluate agribusiness regulatory compliance and consumers’ willingness to pay for a food safety premium among vegetable producers in Kenya. Methodology: The researcher adopted a cross-sectional survey design to randomly recruit a sample of crop farmers (n=118) and vegetable consumers (n=235) from Kirinyaga and Kiambu counties in Kenya, respectively. Data on consumer willingness to pay for safe agricultural produce as well as logistical issues regarding proximity to markets and social status of the crop farmers were collected using a researcher-administered questionnaire in a one-on-one interview. A similar approach was adopted to interview consumers’ social status and vegetable consumption patterns. Results/Findings: The study found that the present commercialization of tomatoes and kales is driven by low-income earners’ bid to earn a livelihood. However, their capital limitations push them to farm outside planned areas such as forests fringes, riverbanks or low potential zones in which they face extraordinary pressure from pests and diseases, which in turn compel them to abuse agrochemicals. This finding also explains their marginalization from county government extension services, high costs of market access and potential to experiment with classified agrochemicals. The study revealed that high income consumer from Westlands (91.44%) were likely to consider agrochemicals in their decisions to purchase vegetables compared to medium and low-income from Kasarani and Embakasi (2.21% and 6.35%), respectively. Majority of the vegetable consumers were not aware of varied agrichemical used by fathers as well as their health and environmental effects.There is reason to believe that both farmers and consumers could be heavily exposed to which the study proposes a population-based survey to assess agrochemical poisoning. Unique contribution to theories, practice and policy: This study finds compelling evidence to suggest that livelihood and farming outcomes of vegetable farmers are a key consideration among consumers purchase decisions. The findings also suggest that these factors significantly incentivize the farmer to comply with agribusiness ethics regulations. The paper recommends a training of extension officers and advocate for more budgetary allocation on agriculture. The extension officers will in turn train farmers on god farming practices as well as implementation of mitigation measures in relation to toxic pesticides. The researcher feels that there is a need to for a research to be conducted to understand the involvement of farmers in the formulation of policies and agribusiness practices rules in order to gain knowledge on the level of acceptance of these polices among farmers in Kenya. Key words: Consumers, Producers, Food-safety, Premium