scholarly journals Geo-hydrological hazard and risk zonation of Banganga watershed using GIS and remote sensing

2001 ◽  
Vol 23 ◽  
Author(s):  
Motilal Ghimire

The present study attempts to analyse the terrain elements and geo-hydrological processes operating on the Banganga watershed in western Nepal. The paper also assesses the hazard and risk to the land use, land cover, and settlements. The Banganga watershed is highly rugged, steep, and fragile. Based on GIS, a geo-hydrological hazard map, a vulnerability map, and a risk map were prepared. In the study area, the geo-hydrological processes are active and intense during the monsoon season. Instabilities are generally found on steep slopes with high relative relief, in areas underlain by the Siwaliks, and along the fault zones. The mass movements are more frequent on slopes covered by dense to moderately dense forest than on the agricultural land. The socio-economic significance of the hazard in the watershed is considerably high. About 8% of the agricultural land lies in the very high and high hazard zones. Similarly, 18 house s are located in the very hazard zone. 93 houses in the high hazard zone, 211 in the moderately high hazard zone, and the rest of 2,185 houses in the moderate and low hazard zones. The risk map generated by combining the hazard map and vulnerability map shows 14% of the area under the very high and high risk zones, 38% under the moderate risk zone, and 48% under the low risk zone.

1970 ◽  
Vol 31 ◽  
pp. 43-50 ◽  
Author(s):  
Pradeep Paudyal ◽  
Megh Raj Dhital

The rocks in the Thankot–Chalnakhel area constitute the Chandragiri Range bordering the Kathmandu valley. The Phulchauki Group of rocks comprise its steep and rugged south slope, whereas the gentle north slope is covered by fluvio-lacustrine deposits of the Kathmandu basin with some recent alluvial fans. During the field study, 94 landslides (covering about 0.24 sq km) were mapped. Most of them were triggered by intense rainfall within the last two years. Landslides are generally found on steep colluvial slope (25°–35°) and dry cultivated land. Based on a computer-based geographical information system, a landslide hazard map, a vulnerability map, and a risk map were prepared. The landslide hazard map shows 20% of the area under high hazard zone, 41% under moderate hazard zone, and 39% under low hazard zone. The risk map generated by combining the hazard map and vulnerability map shows 19% of the area under high and very high risk zones, 33% under moderate risk zone, and 48% under low and very low risk zones.


2021 ◽  
Vol 13 (2) ◽  
pp. 254-264
Author(s):  
Nguyen DUNG ◽  
◽  
Dang MINH ◽  
Bui AN ◽  
Nguyen NGA ◽  
...  

Floods are considered to be one of the most costly natural hazards in the Lam river basin causing infrastructure damages as well as devastating the affected area and relatively high death toll. So prevention is necessary for shielding lives and properties. The flood management on the Lam River basin has been considering for many years to minimize damages caused by flooding. The flood hazard zoning map is one of the indispensable tools to provide information about hazard and risk levels in a particular area and to perform the necessary preventive and preparedness procedures. The multicriteria decision analysis based on geographic information systems is used to build a flood hazard map of the study area. The analytic hierarchy process is applied to extract the weights of six criteria affecting the areas where are prone to flooding hazards, including rainfall, slope, relative slope length, soil, land cover, and drainage density. The results showed in 91.32 % (20103.83 km2) of the basin located in the moderate hazard zones to very high hazard zones. Accordingly, this study also determined 4 vulnerability levels to agricultural land including low, medium, high, and very high. About 94% of the total area of agricultural land in the basin are classified into moderate to the very high hazard of flood vulnerability. The paper presents a method that allows flood risk areas in the Lam River basin to receive information about flood risks on a smartphone, making them more aware.


2021 ◽  
Author(s):  
Dawit Asmare Manderso

Abstract The main goal of this research was to perform a landslide hazard zonation and evaluation around Debre Markos town, North West Ethiopia, found about 300 km from the capital city Addis Ababa. To achieve the aim, a GIS-based probabilistic statistical technique was used to rate the governing factors, followed by geoprocessing in the GIS setting to produce the landslide hazard zonation map. In this research, eight internal causative and external triggering factors were selected: slope material (lithology and soil mass), elevation, aspect, slope, land use land cover, curvature, distance to fault, and distance to drainage. Data were collected from field mapping, secondary maps, and digital elevation models. Systematic and detailed fieldwork had been done for image interpretation and inventory mapping. Accordingly, the past landslides map of the research area was prepared. All influencing factors were statistically analyzed to determine their relationship to previous landslides. The results revealed that 17.15% (40.60 km2), 25.53% (60.45 km2), 28.04% (66.39 km2), 18.93% (44.83 km2), and 10.36% (24.54 km2) of the research area falls under no hazard, low hazard, moderate hazard, high hazard, and very high hazard respectively. The validation of the landslide hazard zonation map reveals that 1%, 2%, 3%, and 94% of past landslides fall in no hazard zone, low hazard, moderate hazard zone, and high hazard or very high hazard zones respectively. The validation of the landslide hazard zonation map thus, it has been adequately demonstrated that the adopted approach has produced acceptable results. The defined hazard zones can practically be utilized for land management and infrastructure construction in the study area.


2016 ◽  
Vol 31 (3) ◽  
pp. 291-298 ◽  
Author(s):  
Aleem Tareen ◽  
Muhammad Rafique ◽  
Kimberlee Kearfot ◽  
Muhammad Basharat ◽  
Bilal Shafique

Soil-based radon investigations are of value in correlating radon production and its transportation into buildings through the processes of convection and diffusion. Such studies can help in identifying land areas that pose special concerns. We present preliminary results of soil radon gas measurements at 60 different locations in an attempt to map out the geohazard zone of the city of Muzaffarabad. The seismic geohazard microzonation for the area includes five microzones based on different hazard parameters: a very high hazard zone, a high hazard zone, a moderate hazard zone, a low hazard zone, and a safe zone. Measurements were taken with an active radon monitoring system at the depths of 30, 40, 50, and 60 cm below the ground surface. The results obtained were explained by the lithology of the area. Average soil radon gas concentrations were correlated with the depth from the ground surface and indoor radon values for the study area. No significant correlation was found between soil radon gas and meteorological parameters, however soil radon gas increases as the depth from the surface of the ground grows. The results showed a linear relation between soil radon concentrations with depth from ground surface (R2 = 0.9577). The minimum soil radon concentration (68.5 Bq/m3) was found at a depth of 30 cm in the very high hazard zone, the maximum value (53.300 Bq/m3) at a depth of 60 cm in the seismically safe zone. Measured soil gas radon concentrations at depths of 30, 40, 50, and 60 cm were mapped for high, moderate, and low radon concentrations. Elevated soil radon gas concentrations were found in the safe zone, otherwise considered to be suitable for any type of construction.


2018 ◽  
Vol 44 (2) ◽  
pp. 211-224
Author(s):  
Maruf Billah ◽  
Mehedi Ahmed Ansary

Risk assessment provides the scope to understand the vulnerability situation of any area based on different hazard context. The study has been conducted in the eastern part of Jamuna floodplain area to examine its flood vulnerability. To perform the analysis, the whole study area has been surveyed and examined applying Geographic Information System. The entire hazard, vulnerability as well as the capacity factors are assessed and have been classified into different categories from very low to very high. Individual factor analysis has been considered to realize the specific condition of different factors. Finally, flood hazard map has been prepared to examine the vulnerability of the proposed area. This type of work helps the planners and disaster managers to identify the most risk zone which should receive immediate hazard mitigation measures as well as help to take a decision in an emergency situation when a flood may occur in the study area. Asiat. Soc. Bangladesh, Sci. 44(2): 211-224, December 2018


2021 ◽  
Author(s):  
Digvijay Singh ◽  
Arnab Laha

<p>Landslides problems are one of the major natural hazards in the mountainous region. Every year due to the increase in anthropogenic factors and changing climate, the problem of landslides is increasing, which leads to huge loss of property and life. Landslide is a common and regular phenomenon in most of the northeastern states of India.  However, in recent past years, Manipur has experienced several landslides including mudslides during the rainy season. Manipur is a geologically young and geodynamically active area with many streams flowing parallel to fault lines. As a first step toward hazard management, a landslide susceptibility map is the prime necessity of the region. In this study, we have prepared a landslide hazard map of the state using freely available earth observations datasets and multi-criteria decision making technique, i.e., Analytic Hierarchy Process (AHP). For this purpose, lithology, rainfall, slope, aspect, relative relief, Topographic Wetness Index, and distance from road, river and fault were used as the parameters in AHP based on the understanding of their influence towards landslide in that region. The hazard map is classified into four hazard zones: Very High, High, Moderate, and Low. About 40% of the state falls under very high and high hazard zone, and the hilly regions such as Senapati and Chandel district are more susceptible to the landslide. Among the factors, slope and rainfall have a more significant contribution towards landslide hazard. It is also observed that areas nearer to NH-39 that lies in the fault zones i.e., Mao is also susceptible to high hazard. The landslide susceptibility map gives an first-hand impression for future land use planning and hazard mitigation purpose.</p>


Author(s):  
A. Ahmed

Integrating malaria data into a decision support system (DSS) using Geographic Information System (GIS) and remote sensing tool can provide timely information and decision makers get prepared to make better and faster decisions which can reduce the damage and minimize the loss caused. This paper attempted to asses and produce maps of malaria prone areas including the most important natural factors. The input data were based on the geospatial factors including climatic, social and Topographic aspects from secondary data. The objective of study is to prepare malaria hazard, Vulnerability, and element at risk map which give the final output, malaria risk map. The malaria hazard analyses were computed using multi criteria evaluation (MCE) using environmental factors such as topographic factors (elevation, slope and flow distance to stream), land use/ land cover and Breeding site were developed and weighted, then weighted overlay technique were computed in ArcGIS software to generate malaria hazard map. The resulting malaria hazard map depicts that 19.2 %, 30.8 %, 25.1 %, 16.6 % and 8.3 % of the District were subjected to very high, high, moderate, low and very low malaria hazard areas respectively. For vulnerability analysis, health station location and speed constant in Spatial Analyst module were used to generate factor maps. For element at risk, land use land cover map were used to generate element at risk map. Finally malaria risk map of the District was generated. Land use land cover map which is the element at risk in the District, the vulnerability map and the hazard map were overlaid. The final output based on this approach is a malaria risk map, which is classified into 5 classes which is Very High-risk area, High-risk area, Moderate risk area, Low risk area and Very low risk area. The risk map produced from the overlay analysis showed that 20.5 %, 11.6 %, 23.8 %, 34.1 % and 26.4 % of the District were subjected to very high, high, moderate, low and very low malaria risk respectively. This help to plan valuable measures to be taken in early warning, monitor, control and prevent malaria epidemics.


Elkawnie ◽  
2017 ◽  
Vol 3 (2) ◽  
Author(s):  
Fathul Mahdariza

In order to minimize the losses caused by lightning, a lightning disaster management system is compulsory. It should provide lightning disaster information in an area to get the risk values of lightning strikes. One way is to establish a lightning disaster risk map. The disaster risk map consists of hazard map, vulnerability map and capacity map. However, lightning yet has not been included in the regulation guiding the establishment of risk map for several disasters in Indonesia. This study is conducted to develop a process to determine general hazard index for lightning disaster.


2017 ◽  
Vol 53 ◽  
pp. 93-98
Author(s):  
Subash Acharya ◽  
Dinesh Pathak

In the hilly and mountainous terrain of Nepal, landslide is the most common natural hazard especially during prolong rainfall. Every year landslide cost lives and causes injuries. In order to address this problem, the best that can be done is to prepare the landslide hazard map of the area, apply mitigation measures and evacuate the high hazardous area, if necessary. Landslide hazard assessment is the primary tool so as to understand the nature and characteristics of the slope that are prone to failure. Logistic Regression Model is used for the preparation of landslide hazard map of the Besi Shahar-Tal area in Marsyangdi River basin in west Nepal. The causative factors such as elevation, slope, slope aspect, land use, geology, rainfall, lineament density, stream density are used. All the thematic layers of these parameters are prepared in GIS and logistic regression analysis is done by using Statistical Package for Social Science (SPSS). Five different hazard zones are separated namely very low hazard zone, low hazard zone, medium hazard zone, high hazard zone and very high hazard zone. The high hazard zone is lying along the Marsyangdi River and its tributaries.


2020 ◽  
Vol 4 (1) ◽  
pp. 19-27
Author(s):  
Heru Sri Naryanto ◽  
Wisyanto Wisyanto

ABSTRACTThe Nganjuk District is mostly planted by forests, both protection forests and production forests with a total area of 20 333.00 ha. Forest and land fires often occur in Nganjuk District, which causes economic and environmental losses. Forest and land fires often cause haze disasters that can disrupt the activities and health of surrounding communities. The forest and land fire hazard map is needed. Making a forest and land fire hazard map of Nganjuk District is carried out with consideration of various parameters, namely: rainfall, land use, altitude, and type of forest. The analysis was carried out using spatial analysis with a scoring system of influential parameters, and from the results of the analysis 3 (three) classifications of fire hazard-prone areas were determined, namely: high hazard, moderate hazard, and low hazard. The five (5) biggest sub-districts included in the forest and high land fire hazard zones in Nganjuk District are the sub-districts: Rejoso, Lengkong, Ngluyu, Gondang, and Jatikalen. Zoning maps of forest and land fire hazards in Nganjuk District are urgently needed in the framework of mitigation, adaptation and disaster management of forest and land fires, as well as sustainable development planning in Nganjuk District. Keywords: Nganjuk, forest and land fires, hazard zone map, mitigation. ABSTRAKKawasan Kabupaten Nganjuk hutan banyak ditumbuhi oleh hutan, baik hutan lindung maupun hutan produksi dengan luas total 20 333.00  ha. Kebakaran hutan dan lahan sering terjadi di Kabupaten Nganjuk, yang menyebabkan kerugian ekonomi dan lingkungan. Kebakaran hutan dan lahan seringkali menyebabkan bencana asap yang dapat mengganggu aktivitas dan kesehatan masyarakat sekitar. Peta zonasi bahaya kebakaran hutan dan lahan sangat diperlukan. Pembuatan peta bahaya kebakaran hutan dan lahan Kabupaten Nganjuk dilakukan dengan pertimbangan berbagai parameter, yaitu: curah hujan, tataguna lahan, ketinggian tempat, dan jenis hutan. Analisis dilakukan dengan menggunakan analisis spasial dengan sistem skoring dari parameter yang berpengaruh, dan dari hasil analisis akan ditetapkan 3 (tiga) klasifikasi daerah rawan bahaya kebakaran yaitu: bahaya tinggi, bahaya sedang, dan bahaya rendah. Lima (5) kecamatan terbesar yang termasuk zona bahaya kebakaran hutan dan lahan tinggi di Kabupaten Nganjuk adalah kecamatan-kecamatan: Rejoso, Lengkong, Ngluyu, Gondang, dan Jatikalen. Peta zonasi bahaya kebakaran hutan dan lahan di Kabupaten Nganjuk sangat diperlukan dalam rangka mitigasi, adaptasi dan penanggulangan bencana kebakaran hutan dan lahan, serta perencanaan pembangunan berkelanjutan di Kabupaten Nganjuk. Kata kunci: Nganjuk, kebakaran hutan dan lahan, peta zonasi bahaya, mitigasi.


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