- Biogeography (19)
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- GIS and Remote Sensing (15)
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- Hydrology (53)
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- Various (30)
Abstract: Panimbang sub-district, located in the subduction zone of the Indo-Australian plate and directly facing Mount Anak Krakatau, is highly vulnerable to tsunami hazards. The region’s geographic location and its coastal topography make it particularly susceptible to the devastating impacts of tsunamis. This study assesses the region’s preparedness to manage tsunami risks using Geographic Information System (GIS) tools to model evacuation routes and estimate potential inundation areas. The research evaluates the effectiveness of the region’s evacuation capacity, considering critical factors such as population distribution, land cover, and the time required for residents to evacuate safely.
The study’s findings indicate that 74.91% of the 512.73 hectares of residential area in Panimbang is at significant risk of tsunami impact, potentially affecting approximately 38,723 people. This high level of exposure underscores the urgent need for tailored evacuation strategies, particularly in densely populated areas, to minimize the risk of casualties. The analysis also highlights the importance of enhancing infrastructure and disaster preparedness plans to increase the resilience of communities most vulnerable to tsunami threats. The research provides valuable insights into the critical elements of tsunami disaster management. It can serve as a crucial reference for future studies focused on improving evacuation routes, shelter planning, and other essential aspects of critical infrastructure. By addressing these areas, future efforts can more effectively safeguard the population in tsunami-prone regions, ensuring a more efficient and organized disaster response that significantly reduces the potential for loss of life and property.
Abstract: The purpose of this study is to identify potentially flood-prone areas in the section between the Siret hydrometric station and the confluence of the Siret River with the Suceava River.
Data related to water flow and specific flow parameters were incorporated into a dedicated hydrodynamic modeling program, in accordance with its requirements (DHI). The construction of the model focused on reproducing the field’s reality as faithfully as possible. Flow parameters were individually configured for each calculation section, taking into account their specific characteristics. Roughness values were determined non-uniformly based on the areas traversed by each cross-sectional profile.
Great emphasis was placed on model calibration, using monitored data from the Zvoriștea and Huțani hydrometric stations as reference points. A time series spanning 15 years, including two of the largest floods recorded in the sector, was used. Following the simulation of two scenarios, Q1% and Q0.1%, three types of files were generated, describing the flood boundary, water depth at each point on the boundary surface and water velocity at each point within the flood boundary. Localities and types of potentially flood-prone surfaces were identified on a map using GIS techniques. Furthermore, flood boundary limits from different scenarios were overlaid to quantify areas at risk of flooding. Although the scenarios were simulated on a previously calibrated model, the fact that the simulated flows exceeded the observed flows required several post-calibration steps. In the case of the first scenario, the simulation did not show significant errors, precisely because the Q1% flow is close in value to the maximum flows observed during the calibration period. In the case of the second scenario, the fact that the flow extended to non-specific areas even during historical maximum flows, resulted in stability errors or non-conforming results obtained by the program, inconsistent with research and studies in the field.
Abstract: Floods are considered one of the most significant natural threats to cities and their infrastructure, especially when urban resilience is weak of floods, due to both human and natural factors. This is the case in the Algerian city of Tebessa, where urban resilience is low in the watershed of Wadi Nagues, which divides the city from north to south. Informal expansion along the riverbanks and inadequate city infrastructure increases the risk of flooding in the city. This study aims to identify the factors that increase flood hazards in Wadi Nagues and analyze maximum daily rainfall values to determine the maximum flood flow and volume during different return periods of 10, 50, 100, and 200 years, in order to map the floodplain of the river. This is accomplished using Geographic Information Systems (GIS) and HEC-RAS software for flood simulation. The results of the flood simulation in Wadi Nagues show that river waters inundate the southern areas of informal expansion, the airport, the railway, Houari Boumediene neighborhoods, and the Constantine Road – which is an economic artery for the city. The peak flow reaches 86.82 m³/h, and the volume of flow is 159.20 m³/s, in a during a 200-year return period. Field surveys also reveal several other human factors that increase the risk of flooding, such as informal expansion, lack and weakness of flood protection hydraulic structures, and poor river water cleanliness. This necessitates intervention to protect the city from flood hazard.
Abstract: Seasonal quality assessment of surface water provides not only a better understanding about pollution dynamics in water bodies but also information for the implementation of sustainable water-use management strategies. Such vital information is lacking for surface waters in most cities in sub-Sahara Africa region, especially Nigeria. The study aimed, therefore, to examine the seasonal physio-chemical characteristics of surface waters in Enugu urban, southeast Nigeria, during the dry and wet seasons. Twelve Surface water samples were collected from the six major rivers in Enugu urban during two seasons (wet and dry seasons). Their physico-chemical characteristics were determined by specific analyses between 2020 and 2022. Some of the parameters were measured in situ whereas bacterial analysis were analysed in the laboratory. Seasonal fluctuations in surface water quality characteristics were determined and the pollution status was compared to WHO standards. The results revealed that the parameters like Turbidity, Ammonia, Nitrate, Nitrogen, Fecal coliform and total coliform were above the WHO permissible limit at all sites and for all seasons. Various anthropogenic activities, untreated sewage and effluent were the major sources of pollution to the river ecology and the surface water. Overall monitoring network results must be used to control pollution in catchments where industrial and urban activities are increasing in other to ensure effective water quality management, sustainability and safety.
Abstract: River bank erosion within Murshidabad district is a tragedy, which happens haphazardly along the bank of the Padma River system. The main objective of the study is to analyze the changing river course and its impact on society. By comparing the toposheet and Landsat (5 and 8) images of the Padma River of the Murshidabad district from the years 1924, 1990, and 2020, it is clearly observed that there have been significant changes on the southern portion of the river since 1924 (Bhagawangola II, Raninagar II, and Jalangi Block), while less changes occur on the central part of the river, which is near the Lalgola block. But in the year 2020 significant changes have been found in the northern and middle portion of the district near Samserganj and Lalgola block. Those parts belong to a highly vulnerable zone of bank erosion. This study analyzed some factors, such as soil stratification of the river bank and human encroachment as an obstruction to the natural river flow, also responsible for bank failure. The river has been consuming the vast portions of the right bank every year due to its increasing sinuosity. The victims are mostly in the Samserganj, Lalgola, Bhagawangola II, Raninagar II and Jalangi blocks, who suffered greatly from 1924 to 2020 due to moving of river course by 27% on the right side, which is notified from cross sectional analysis. Additionally, the predicted erosional impact of the region highlights the socio-economic perspective of the research area.
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