Moderate Zones Research Articles

ZONASI TINGKAT KERENTANAN TERHADAP BENCANA BANJIR DI KECAMATAN GUNUNG PUTRI KABUPATEN BOGOR

Flood is a phenomenon of submerging or inundating of an area. Based on the Bogor Regency Regional Regulation No. 4 of 2019 concerning the 2018-2023 Regional Medium-Term Development Plan, there are seven sub-districts in Bogor Regency that have a high level of vulnerability to flood disasters. One of these sub-districts is Gunung Putri District. This sub-district is the worst and most affected by the flood disaster due to the overflow of the Cikeas River and the Cileungsi River that surrounds it during high rainfall intensity for a long time. The purpose of this research is to arrange zoning based on the level of vulnerability to flood disasters. The method used is overlay and scoring techniques. The level of vulnerability is determined based on the river buffer, elevation, slope, and land use. The results showed a zoning map of the level of flood vulnerability in Gunung Putri District. The zone with a high level of flood vulnerability is 3864.83 Ha, the moderate zone is 1662.87 Ha, and the low is 561.68 Ha from the area of Gunung Putri District.

Enhancing the success of new dams implantation under semi-arid climate, based on a multicriteria analysis approach: Case of Marrakech region (Central Morocco)

Abstract Water management has become one of the major interests in arid and semi-arid regions. Scientists have suggested different criteria and methodologies for the identification of suitable dam sites. According to our literature review, we have used two major methodologies for the selection of suitable dam site location: geographic information system and remote sensing (GIS/RS) and multicriteria analysis (MCA) integrated with GIS/RS. The most common criteria used for the selection of suitable dam sites were slope, rainfall, land use land cover, soil type, lithology, lineament density, and hydrographic typology. All the factors were superimposed to prepare the synthesis map of water-harvesting structures, each thematic layer’s weight was determined, and storage water potential indices were calculated using water accumulation conditions. According to the water-harvesting location map, where the spatial distribution of the excellent (5%), very good (9%), and good (17%) aptitude classes is established in the northeast and central parts of the westward zone, the average located in the center of the zone. Study and weak are located south of the map; the area of moderate (25%) to poor (44%) suitability is situated in the south and southwest zone. The MCA was validated using an existing dam across the study area, where the MCA provides for the dam located in the good and moderate zones. The approach adopted in this study can be applied for any other location globally to identify potential dam-construction sites. From the point of view of the literature of multicriteria analyses of water recovery, areas unsuitable for surface water harvesting and dam projects are suitable for groundwater recharge.

Reducing sea cliffs hazards in pocket beaches through beach nourishment on the Barlavento Coast (Algarve, Portugal)

Tourism based on “sun and beach” is the main economic activity in the Algarve region. A considerable part of the beaches of the Barlavento coast corresponds to embedded sand accumulated along the irregular lacework-like coastline of rocky cliffs cut into Miocene calcarenites. The pattern of touristic occupation in the Algarve and the geodynamics of the rocky sea cliffs, characterized by discontinuous and intermittent occurrence of slope mass movements, result in a high level of risk to beach users along pocket beaches. In order to mitigate the risk associated with the cliff geodynamics, artificial beach nourishment was performed in Castelo and Coelha pocket beaches on the Barlavento Coast, in 2014, increasing the beach area by 3.5 times. The effects of the beach nourishment on the occupation patterns of those beaches along the 2006-2016 decade, before and after the beach nourishment, are herein presented and discussed. Occupancy data were obtained covering different seasons along the year, by counting the number of beach users, regardless of age, using periodic and systematic photographs taken at strategic points that provide full coverage of the beach areas. Before the beach nourishments the area of dry sand outside high and moderate hazard zones, measured at half-tide under average summer wave conditions was 500 m2 at Coelha beach and 800 m2 at Castelo beach. After beach nourishment the same area increased to 6700 m2 at Coelha beach and 7100 m2 at Castelo beach. Results show that, following the beach fill, beach occupation by recreational users naturally shifted seaward, moving out from the cliff hazard areas. After the intervention, the occupation of high and moderate hazard areas reduced significantly, from 37 % to 11 % in Castelo beach and from 59 % to 27 % in Coelha beach. Keywords: beach nourishment; hazard; rocky cliffs; Algarve; Portugal.

Performance of a Solar Spectrum-Selective Absorption Film as a Building Energy-Saving Retrofit in China.

The transparent envelope structures in existing buildings have caused so much energy consumption. As one kind of the energy-saving technologies and strategies, the solar spectrum selective absorption film (SSAF) is considered suitable for the retrofit of glazing systems. The energy-saving performance of the SSAF in different types of glazing systems under different climate zones in China was investigated via a field study and simulation experiment. The results indicated that SSAF slowed down the rise of indoor air temperature in the daytime and reduced the total energy entering the room. The effect of the SSAF on the single glazing system was more potent than that on the double glazing system. In the hot summer and cold winter zone, moderate zone, hot summer and warm winter zone, the SSAF could reduce the energy consumption of windows. The highest energy-saving rate reached 35.0% for the single glazing system and 28.3% for the double glazing system. However, the SSAF does not have the energy-saving potential in existing buildings that already have low-E double glazing systems.

Exploration of groundwater potential zones using analytical hierarchical process (AHP) approach in the Godavari river basin of Maharashtra in India

Total natural and groundwater resources play the most crucial role in developing ecological, biological and socioeconomic doings. Various parameters like land use, geology, elevation, slope, lineament, lineament density, drainage density and geomorphology affect the groundwater development of recharge and its accessibility. In this research, geographical information system (GIS), remote sensing, weighted overlay analysis and analytical hierarchy process (AHP) methods have been used for groundwater prospects mapping, and identifying suitable solutions site for soil and water conservation structures. To calculate the weights were assigned to every layers component in the determination of affecting factors. The weighted overlay analysis (WOA) tool is applied to give the sub-parameter ratings based on the scientific literature. The final map of potential groundwater zone map has prepared using Arc GIS 10.1 software and AHP methods. About 49.71% of the areas fall under the 'good potential zone, 41.05% falls under the 'moderate potential zone', and 9.22% falls under the 'poor zone by using AHP technique. Groundwater potential zone map is depend on the weighted overlay analysis and analytical hierarchy process (AHP) methods. The highest GWP is located in the lower part of the basin due to the best surface runoff gathering, infiltration situations and subsurface storage volume. The present study procedure, methods and outcomes can be valuable to estimate the suitable groundwater zones parallel to improve the dry land area in the semi-arid and arid regions of India.

Three‐Dimensional Electrical Resistivity Characterization of Mountain Pass, California and Surrounding Region

AbstractThe Sulphide Queen carbonatite deposit at Mountain Pass in southeast California is a world class rare earth element (REE) resource. This study images electrical resistivity structure of the REE deposit and surrounding area to characterize resources under cover. An east‐west elongated grid (35 × 15 km) of 65 wideband magnetotelluric stations spanning from eastern Shadow Valley to eastern Ivanpah Valley were collected and modeled in three‐dimensions (3‐D). Gravity, aeromagnetic, and geologic data are used to inform interpretation of structures in the resistivity model, including the following observations. Shadow Valley is filled with conductive sediment that locally dips southward to a depth of 1 km. The Kingston Range‐Halloran Hills detachment fault dips westward at ∼15 degrees. The REE deposit is a moderate low resistivity zone dipping southwest to a possible depth of ∼1 km, and is bounded by the North and South faults and bisected by the Middle fault. Ivanpah Dry Lake is underlain by a north striking southward dipping sedimentary basin. Two possible zones of mineralization are observed in Ivanpah Valley, one along the western edge of Ivanpah Dry Lake and one on the western edge of valley along a new inferred fault. The brittle‐ductile transition is imaged at ∼10 km below mean sea level. No deep electrically conductive structures are imaged to be related to the REE deposit likely due to the complex geologic history of the Mojave terrane. Future studies should regional target Proterozoic rocks and search within for geophysical signatures similar to Mountain Pass.

Application of earth observation dataset and multi-criteria decision-making technique for forest fire risk assessment in Sikkim, India

Forest fire is one of the primary and recurring problems in Sikkim, India impacting the ecological heritage of the region. The article presents a fire risk model based on the identification of the major factors that contribute to forest fire, namely, vegetation type, vegetation density, land surface temperature, elevation, slope, aspect, and distance from settlements, rivers and roads, and then integrating them using a multi-criteria decision-making technique in a GIS framework. We document that more than 50% of the area of all the districts except North Sikkim falls into high to moderate risk zones. The model shows that 61% of fire information for resource management system data for the last 16 years coincide with the mapped high-risk zone of the state. Areas with low slope and with moderate vegetation density fall into very high risk, whereas areas with high slope and with high vegetation density correspond to moderate risk zones. Further, aspect and density of human intervention differentiate the very high and high-risk zones of the region. This model has provided a robust geographical representation of fire ignition probability and identification of high-risk areas at different regions for the entire state of Sikkim

UAV technique to localize landslide susceptibility and mitigation proposal: A case of Rinchending Goenpa landslide in Bhutan

Natural hazards such as landslides impose very high risks to the community and infrastructures. To mitigate such risk, proper long-term engineering solutions are must. Several studies conducted in the past proposed countermeasures on many occasions. Despite such interventions, the Rinchending Goenpa area still suffers high vulnerability to landslide hazard which continues every monsoon. To assess landslide characteristics in detail, we performed landslide susceptibility mapping using the unmanned aerial vehicle (UAV) technique and conducted a site investigation. High-resolution digital elevation model (DEM) was generated with the site-specific aerial photographs and processed in Agisoft PhotoScan to developed thematic layers in geographical information system (GIS) software. We implemented a multi-influencing factor (MIF) for deriving the influence of landslide conditioning factors and developed a landslide susceptibility map (LSM) using the weighted overlay method (WOM). The landslide conditioning factors include slope, elevation, aspect, topographical wetness index (TWI), and normalized difference vegetation index (NDVI). According to LSM, the areal coverage of landslide susceptibility of study area reveals 2.41% in very low susceptibility, 37.14% in low susceptibility, with highest in moderate susceptibility zone of 49.55% followed by 10.60% in high susceptibility zone, and 0.30% in the very high susceptible zone. Based on the zonal distribution of LSM, and considering findings from several other site investigation such as geophysical survey, the performance of existing countermeasures, soil characteristics, and footprint of last landslide occurrences, we proposed mitigation measures under each zone to provide long-term solutions.

Evaluation of chemical profiles and biological properties of Gliricidia sepium (Jacq.) Walp. volatile oils from Nigeria

Volatile oils obtained by hydrodistillation from Gliricidia sepium (Jacq.) Walp. leaf and stem were examined for their chemical composition and biological activity. The oils were analyzed by gas chromatographic-mass spectrometric (GC-MS) techniques. Toxicity, antimicrobial and antioxidant activities were evaluated via brine shrimp lethality assay, agar-diffusion, and DPPH radical-scavenging methods, respectively. A total of 43 and 44 constituents were identified in the leaf and stem oils, correspondingly. The major components recognized in the leaf oil were (E)-hexadecatrienal (16.9%) and pentadecanal (16.0%) while humulene epoxide II (17.5%) and caryophyllene oxide (10.6%) dominated the stem oil. There was no significant activity against the bacteria but moderate inhibition zones (IZ) between 1.8±0.3 and 8.1±0.1 mm were observed against the fungi. The stem oil showed better antifungal activity than the leaf oil but not as active as the standard drug ketoconazole which inhibited the test fungi with IZ range of 10.4±0.4-21.0±1.4 mm at 200 μg. Both oils were toxic to brine shrimp (Artemia salina) giving LC50 of 79.7 μg/mL (leaf) and 38.7 μg/mL (stem). The leaf and stem oils had IC50 of 84.3 μg/mL and 142.2μg/mL, respectively, in the DPPH radical-scavenging assay, indicating moderate antioxidant activity relative to positive controls, butylated hydroxylanisole (IC50=45.1 μg/mL) and α-tocopherol (IC50 =81.6 μg/mL). The results suggest that G. sepium volatile oil may find potential use as a natural antioxidant and antifungal agent.

Hydro-Geoelectrical Study for Groundwater Potential of Lassa And Environs, North Eastern Nigeria

Twenty-two Vertical Electrical Sounding (VES) were carried out to evaluate groundwater potential and aquifer protective capacity of the overburden units using Schlumberger configuration. It was observed that H-curve is the dominant curve type in the study area. The Geo-electro stratigraphic section revealed that the geologic sequence beneath the study area is composed of topsoil, highly weather basement, partly fractured basement and fresh basement. The first layer has an average thickness and resistivity of 1 m and 130 Ωm, respectively. The second layer has an average thickness of 14 m and an average resistivity of 53 Ωm. The third layer is partly fracture basement with an average resistivity of 747 Ωm while at some VES point represents fresh basement. The highly weathered basement and partly fracture basement layer make up the water bearing formation of the area. Dar-Zarrouk parameter revealed that the area under study has protective capacity range from weak to good capacity of the overburden material. Areas that are classified as poor and weak are indicative areas are thus vulnerable to infiltration of leachate and other surface contaminations. The groundwater potential of the area ranges from low to moderate potential; the moderate zone constitutes 86% while the low potential constitutes 14% of the study area. The transverse resistance within the study area ranges from 119.6 to 6983.7 ohms-m2 with an average value of 1024.59 ohms-m2. Hydraulic conductivity values determined from geoelectrical technique range from 3.05 to 38.04 m/day with an average value of 14.86 m/day.

Seedling Diversity Considerably Changes Near Localities in Three Salinity Zones of Sundarbans Mangrove Forest, Bangladesh

The status of natural seedlings near localities in the Sundarbans Mangrove Forest was assessed through a stratified random sampling method to observe seedling composition and diversity, importance value index, family importance value, and species evenness. A total of 63 sample plots of 3,990 m2 area were surveyed in three natural and anthropogenic influenced salinity zones of Sundarbans. A total of 16,166 seedlings of 15 species under 12 families were found. Family Euphorbiaceae showed the highest (59.59%) family relative density and Rhizophoraceae presented the highest (20%) family relative diversity Index (FRDI). The maximum family importance value (FIV) showed by Euphorbiaceae (66.26) and the maximum importance value index (IVI) of species has been observed in Excoecaria agallocha (114.74). Excoecaria agallocha showed the highest relative density (59.6%) and relative abundance (39.87%) where the highest relative frequency (15.27%) was observed by Heritiera fomes. The mean stem density and species diversity index in the whole survey area was 2701 stem ha-1 and 0.0009 correspondingly. The Shannon-Wienner's diversity index was 1.52 where the maximum Shannon-Wienner's diversity index was 2.708. The Simpson's diversity index and Dominance of Simpson index were 0.38 and 0.62 with Simpson's reciprocal index 2.632. The Species evenness index, Menhinick’s, and Margalef's indices were 0.561, 0.118, and 1.445 respectively. The Species diversity index of the three salinity zones were 0.0017, 0.0029, and 0.0035 respectively. The Shannon-Wienner's diversity index of Low Salinity Zone (LSZ), Moderate Salinity Zone (MSZ), and Strong Salinity Zone (SSZ) were 0.887, 1.369, and 1.845 correspondingly where LSZ (0.632) showed the highest Simpson's diversity index follow ed by MSZ (0.394) and SSZ (0.21). The Species evenness index for LSZ, MSZ, and SSZ were 0.346, 0.505, and 0.742 where Menhinick’s Index were 0.148, 0.210, and 0.207 respectively. The analysis showed poor diversity indices and the area was dominated by few species with few families. The status is also reduced with increasing salinity.

Identification and modelling of forest fire severity and risk zones in the Cross – Niger transition forest with remotely sensed satellite data

Forest fires are a serious environmental hazard within the forest ecosystem, which can be studied with Remote Sensing and GIS. The aim of the study is to identify and model forest fires severity and risk zones within the Cross – Niger transition forest. To achieve this aim, remotely sensed data, such as Landsat – 8 OLI (2020) and ASTER DEM were used to produce land cover maps and topography parameters such as aspect, elevation and slope. The topographic maps and the Google Earth imagery were used to extract human settlements and road networks. The final forest fire risk zone (FFRZ) map was prepared by integrating the different parameters such as Land cover, aspect, elevation, slope, proximities to roads and settlements in the ArcGIS environment. The FFRZ was categorized into three categories as low, moderate and high risk zones, based on their fire susceptibility. The category of low, moderate and high FFRZ were represented as 2731.7 km2 (12.5%), 17997.69 km2 (82.59 %) and 1061.63 km2 (4.87%) respectively. The study shows that Remote Sensing and GIS are excellent tools for modelling forest fire risk zones, hence proving that fires are anthropogenic in origin.

Biochemical Profile and Antibacterial Examination of Freshwater Crab Scylla Serrata (FORSKAL, 1775)

Natural products from the aquatic organisms provide unlimited opportunities for the production of new drugs. To verify this fact in the present study ‘the biochemical profile and antimicrobial activity of different samples of the estuarine crab, Sylla serrata’ was investigated. Biochemical study of the body parts of the crab gains substantial attention for their specificity in connection to the food values of the crab and for the evaluation of their physiological needs at different periods of life. The total protein was estimated by Lowry's method and the amount of protein was highest in the soft muscle sample (20.27mg/ml). The total sugar was estimated by the Phenol-Sulphuric acid method and it was highest in the leg sample (209.8mg/ml). The lipids of the samples were estimated by Folchs method. Lipid was highest in the shell sample (28.35mg/ml). Thin Layer chromatography was done for characterization of protein. Antibiotics are used against bacterial infections. The natural products gained importance to screen antibiotics. For this reason the antibacterial activity of the samples were tested against grampositive and gramnegative pathogenic bacterial strains. The bacterial strains like Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Enterobacter aerogenes were used as the test strains. In the present study, the ethanol extract of crab sample I showed maximum zone of inhibition (13 mm) in P. aeruginosa. The sample I showed moderate zone of inhibition (11 mm) in K.pneumoniae. The sample II showed the minimum zone of inhibition (7 mm) in P. aeruginosa. It indicated that the shell of crabs would be a good source of antimicrobial agents and would replace the existing inadequate and cost effective antibiotics. The microbial associates of crustaceans have proven to be a rich source of bioactivity with antimicrobial and cytotoxic effects. So the organism used in the present study will be the promising source to the biotechnological and pharmaceutical applications.

Modelling of mid-rise concrete shear walls reinforced with superelastic shape memory alloys: Nonlinear analysis

The response of hybrid Shape Memory Alloy (SMA)-steel reinforced concrete shear walls containing Nickel-Titanium superelastic SMA as alternative reinforcement in the plastic hinge region was investigated using nonlinear finite element modelling. The hybrid wall system promotes self-centering and significant reduction of permanent deformations. Two types of conventional steel-reinforced concrete shear walls were designed for a prototype 10-storey office building according to the current Canadian concrete design standard, assuming two distinct seismic design scenarios. A moderately ductile shear wall was designed for a moderate seismic zone in eastern Canada, whereas a ductile shear wall was designed for a high seismic zone in western Canada. Equivalent, hybrid SMA-steel reinforced concrete shear walls were defined following the design of the two conventional shear walls, in terms of geometry and reinforcement layout. Full-scale, two-dimensional finite element models were developed to assess the pushover and hysteretic responses of the walls. Similarities in wall cross-section and yield force capacity of the steel and SMA reinforcement permitted a comparison between the walls, including strength, stiffness, self-centering, and energy dissipation capacities. The results indicate similar lateral strength and displacement capacities, and superior restoring capacity of the SMA-reinforced walls in comparison to the steel-reinforced walls. Furthermore, a preliminary study was conducted to investigate the effect of the SMA-bar length in the ductile wall due to concentration of damage near the base of the wall. Lengths corresponding to approximately 50% and 20% of the original SMA length were considered. Based on the analyses, a satisfactory response could be achieved with shorter SMA reinforcing bars, which reduces the quantity of SMA reinforcement without significant loss in self-centering capacity.

A GIS-Based Multicriteria Decision for Groundwater Potential Zone in the West Desert of Iraq

In arid and semi-arid parts worldwide, the investigation of the groundwater potential recharging zone is a main target to recompense the massive shortage in rainfall and surface water supplies. Recently, the combination of Remote Sensing (RS) and Geographical Information System (GIS) techniques became possible to overcome the water scarcity and supply all the water requirements for the population, agricultural and commercial purposes in the western Iraqi desert. Various thematic layers such as geology, slope, soil infiltration, land use and land cover, rainfall, drainage density, and lineament density were derived from RS data like Landsat 8 satellite images and the SRTM Digital Elevation Model (DEM) and published Iraqi geological maps. The thematic map of the parameters was generated and transferred into the raster form by employing the raster conversion tool in ArcGIS 10.8 software, and each layer was subjected to different assigned weights through adopting Analytical Hierarchical Process (AHP). The prospective map of the groundwater recharging zone in the study region is categorized into five regions. The output map shows that 3.21% of the area locates in the perfect potentiality zone, followed by 10.75% in the good potentiality zone, 38.6% moderate potential zone, 42.9% in the poor groundwater zone, whereas only 4.44% of the study area falls under the very high prospective zone. To attain the sustainable management of the groundwater in the Iraqi western desert, this study provides a primary methodology and significant database for the local management of water resources by adopting the groundwater perspective map.

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.

Spatiotemporal Flood Risk Determination and Management for a Large River Basin

The Chao Phraya River Basin (CPRB) of Thailand faces flooding almost every year. The severest flood occurred in the CPRB in 2011 with the highest property damage costs (46.5 billion USD) and the highest casualty (813 deaths). The objectives of this study were thus to (1) determine flood risk indices and categorize them into four risk zones (low, moderate, high, and very high) across 994 sub-districts in the CPRB during the six rainy months (May–October); and (2) propose specific measures for flood risk management for each of the categorized risk zones. The flood risk indices were assessed as the product of two hazard variables (flood levels and monthly cumulative precipitation) and the vulnerability variable (land uses). The findings revealed spatiotemporal variations in flood risk. Spatially, the sub-districts deemed to be in the high or very high flood risk zone were mainly located close to the Chao Phraya River (CPR), where the flood levels reached 1.1 – 4 m in depth; whereas the sub-districts detected in the low or moderate flood risk zone were located further away from the CPR. Temporally, more sub-districts were detected in the high or very high risk zone in September when heavy rainfalls were observed. Specific measures are proposed herein to manage flood risk regarding the categorized zones during three periods. The preventive and mitigation measures should be prepared before flooding; emergency responses should be practically implemented during flooding; and the recovery after flooding should cover both infrastructural and environmental damage and mental/physical illnesses amongst the affected people. Intensive measures are recommended for the sub-districts located in both the high and very high risk zones. These measures may be properly loosened for the sub-districts located in the low and moderate risk zones.

Numerical Simulation and Modeling on CO2 Sequestration Coupled with Enhanced Gas Recovery in Shale Gas Reservoirs

CO2 geological sequestration in shale is a promising method to mitigate global warming caused by greenhouse gas emissions as well as to enhance the gas recovery to some degree, which effectively addresses the problems related to energy demand and climate change. With the data from the New Albany Shale in the Illinois Basin in the United States, the CMG-GEM simulator is applied to establish a numerical model to evaluate the feasibility of CO2 sequestration in shale gas reservoirs with potential enhanced gas recovery (EGR). To represent the matrix, natural fractures, and hydraulic fractures in shale gas reservoirs, a multicontinua porous medium model will be developed. Darcy’s and Forchheimer’s models and desorption-adsorption models with a mixing rule will be incorporated into the multicontinua numerical model to depict the three-stage flow mechanism, including convective gas flow mainly in fractures, dispersive gas transport in macropores, and CH4-CO2 competitive sorption phenomenon in micropores. With the established shale reservoir model, different CO2 injection schemes (continuous injection vs. pulse injection) for CO2 sequestration in shale gas reservoirs are investigated. Meanwhile, a sensitivity analysis of the reservoir permeability between the hydraulic fractures of production and injection wells is conducted to quantify its influence on reservoir performance. The permeability multipliers are 10, 100, and 1,000 for the sensitivity study. The results indicate that CO2 can be effectively sequestered in shale reservoirs. But the EGR of both injection schemes does not perform well as expected. In the field application, it is necessary to take the efficiency of supplemental energy utilization, the CO2 sequestration ratio, and the effect of injected CO2 on the purity of produced methane into consideration to design an optimal execution plan. The case with a permeability multiplier of 1,000 meets the demand for both CO2 sequestration and EGR, which indicates that a moderate secondary stimulation zone needs to be formed between the primary hydraulic fractures of injection and production wells to facilitate the efficient energy transfer between interwell as well as to prevent CO2 from channeling. To meet the demand for CO2 sequestration in shale gas reservoirs with EGR, advanced and effective fracking is essential.

Modern eco-geochemical background of Lebedinsky ferruginous quartzite deposit in the Kursk Magnetic Anomaly

A mine exerts a strong integrated impact on all environmental components, which ends with their transformation or, often, total degradation. The object of the study is the open-pit mining area of Lebedinsky GOK and the adjacent territories in the Kursk Magnetic Anomaly (KMA). The subject of the research is the current ecological and geochemical situation at Lebedinsky GOK and at pit dumps. The authors carried out the comprehensive analysis of the current ecosystems at the Lebedinsky surface mining and dumping facilities, with the identification of 3 severe impact zones: significant ecosystem degradation zone, moderate ecosystem degradation zone, relatively satisfactory ecological situation zone. The soil contamination studies in the sanitary protection zone of Lebedinsky GOK were also carried out at the depths of 0–5 and 5–20 cm. In particular, the distribution of lead, copper, zinc and arsenic concentrations in soil samples was analyzed, and the index of total chemical pollution (Zc) was calculated. The obtained data allowed the authors to clarify the geochemical situation in the area of the open pit and dumps based using the earlier research data collected starting from 2005. According to the total soil contamination index, the study area can be subdivided into 2 sub-areas. The first sub-area is agrolandscapes, forests, gullies, and is characterized by the relatively satisfactory condition of soils (Zc up to 16). In the second subarea, the local sites with moderately hazardous soil pollution are observed (Zc from 16 to 32) in the territory of the open pit and overburden dump. The forecast of changes in the ecological and geochemical situation in the area of KMA mines is made with regard to potential expansion of production activities.