scholarly journals Geospatial Approach for the Assessment and Analysis of Flood Risk in the region of Nanjangud town, Mysore District, Karnataka, India

2021 ◽  
Vol 1197 (1) ◽  
pp. 012032
Author(s):  
Arunkumar Yadav ◽  
H C Hema ◽  
Pramodkumar Kappadi ◽  
Chandrashekharappa Agasnalli
Keyword(s):  
Rural Areas ◽  
Flood Risk ◽  
Urban Areas ◽  
Water Cycle ◽  
Flood Hazard ◽  
Rainfall Variability ◽  
Meteorological Parameter ◽  
Satellite Image ◽  
Geographical Information ◽  
Topographic Map

Abstract Flooding in urban and rural areas is one of the utmost challenges to human safety. Destruction of the properties is the main issue in urban areas and damage to the agriculture practices in the rural area. Flood risk is rising significantly all over the globe. The regional water cycle and water resource availability are governed by the rainfall event, which is a fundamental meteorological parameter. The objective of the study is to examine the rainfall variability for 25 years from the period from 1995 to 2020 for monthly and annual rainfalls in the part of Nanjangud taluk, Mysore district, Karnataka. During the last three years that is 2017 to 2019 during the southwest monsoon, it is noted that the severity of flood increased in the surrounding of Nanjangud town, due to the heavy rainfall and excess amount of water released has augmented the inflow source of flooding. The assimilation of Remotely Sensing (RS) and Geographical Information System (GIS) is capable to generate a sequence of thematic maps that were helpful to create geospatial data for demarcating flood hazard areas. This study discusses the probable flood risk-prone regions of the Kabini river basin near Nanjangud town based on the multi-ring buffered layer analysis. The buffered layers created for the radius of 250m, 500m 750m, and 1000m were overlaid on the Sentinel-2 satellite image and topographic map to delineate the flood-affected region. To calculate the slope and drainage density, the SRTM DEM data was used. Structural and nonstructural practices are proposed in this study can be implemented to reduce the probability of the effect of floods.

Management of Water Cycle: An Approach to Urban Ecology

1992 ◽  
Vol 27 (2) ◽  
pp. 221-238 ◽  
Author(s):  
W. Ripl
Keyword(s):  
Rural Areas ◽  
Urban Areas ◽  
Water Cycle ◽  
Cooling System ◽  
Thermal Power ◽  
Sewage Treatment ◽  
Balance Sheet ◽  
River System ◽  
Soil Restoration ◽  
Environmental Damage

Abstract Densely populated urban areas, which have developed over the last century, depend heavily on centralized water supply, sewage treatment plants, and hydroelectric or thermal power generation with vast demand of cooling water. Considerable areas have been drained or sealed, and the short-circuited water cycle has been distorted. Large rivers have been converted to shipping canals with the permanent risk of accidental pollution. Technical means such as sewage treatment, air filters, emission control and lake and soil restoration measures have contributed to correct the environmental damage. However, a balance sheet for irreversible matter losses (mainly base cation charges) from the urbanized areas and the surrounding landscape into the sea shows ever-increasing trends. These losses are destabilizing the ecosystems. In this paper, management of the water cycle in urban areas, together with the coupled matter cycles, is discussed. Particular reference is given to Metropolitan Berlin, with a network of shipping canals, which move biologically treated waste, containing base cations and nutrients to the surrounding rural areas. This could create manageable productive wetlands and re-establish soil fertility. At the same time, the natural cooling system close to the urban areas will be improved by providing more areas with permanent vegetation. In addition, reduction of the present large oscillations of the groundwater table, resulting from groundwater pumping and its recharge with less polluted surface water, is contemplated. The widely used shoreline infiltration of the Havel River should then be eliminated and the severe damage of the littoral vegetation in large sections of the Havel River system be avoided.

scholarly journals Multi-Criteria Evaluation (MCE) Method for the Management of Woodland Plantations in Floodplain Areas

2020 ◽  
Vol 9 (12) ◽  
pp. 725
Author(s):  
Christos Tzioutzios ◽  
Aristeidis Kastridis
Keyword(s):  
Spatial Analysis ◽  
Rural Areas ◽  
Flood Risk ◽  
Risk Mitigation ◽  
Low Cost ◽  
River System ◽  
Open Water ◽  
Geographical Information ◽  
Multi Criteria Evaluation ◽  
Total Study Area

The potential of woodland and floodplain woodland plantations in a wide area, of high flood risk, along the Spey River (Scotland) is investigated, to mitigate the floods’ catastrophic impact. The spatial analysis required various datasets to be overlaid, to define the suitable sites for woodland and floodplain woodland establishment. These datasets that concern the topography, the physical and technical characteristics (existing woodland, road system, urban and rural areas, river system and open water areas, railway) and the protected sites of the study area were obtained and merged using Geographical Information System (GIS) techniques. The most suitable and unsuitable areas within the region were identified, using multi-criteria evaluation methods (Boolean approach). In total, 13 constraints were created by expressing true/false statements for each factor, and were combined together using spatial analysis tools. The results revealed the high potential of woodland and floodplain woodland plantations to prevent floods, with 59.2% of the total study area (177.5 km2) determined to be appropriate for such practices’ application. The River Dulnain tributary demonstrated the highest potential for floodplain woodland planting, followed by Rivers Avon and Fiddich, and the southwestern and northeastern Spey River parts. The methodology proposed is simple and provides rapid and accurate results at low cost, while the datasets can be easily accessed and are available in convenient type/format. This useful methodology for researchers and authorities could be applied successfully to similar watersheds, contributing significantly to flood risk mitigation and the enhancement of the flood-preventative measures’ planning efficiency.

scholarly journals Regional debris flow susceptibility analysis in mountainous peri-urban areas through morphometric and land cover indicators

2014 ◽  
Vol 14 (11) ◽  
pp. 3043-3064 ◽  
Author(s):  
M. C. Rogelis ◽  
M. Werner
Keyword(s):  
Land Cover ◽  
Debris Flow ◽  
Flood Risk ◽  
Urban Areas ◽  
Debris Flows ◽  
Flood Hazard ◽  
Flow Direction ◽  
Hazard Analysis ◽  
Principal Component ◽  
Debris Flow Susceptibility

Abstract. A method for assessing regional debris flow susceptibility at the watershed scale, based on an index composed of a morphometric indicator and a land cover indicator, is proposed and applied in 106 peri-urban mountainous watersheds in Bogotá, Colombia. The indicator of debris flow susceptibility is obtained from readily available information common to most peri-urban mountainous areas and can be used to prioritise watersheds that can subsequently be subjected to detailed hazard analysis. Susceptibility is considered to increase with flashiness and the possibility of debris flows occurring. Morphological variables recognised in the literature to significantly influence flashiness and occurrence of debris flows are used to construct the morphometric indicator by applying principal component analysis. Subsequently, this indicator is compared with the results of debris flow propagation to assess its capacity in identifying the morphological conditions of a watershed that make it able to transport debris flows. Propagation of debris flows was carried out using the Modified Single Flow Direction algorithm, following identification of source areas by applying thresholds identified in the slope–area curve of the watersheds. Results show that the morphometric variables can be grouped into four indicators: size, shape, hypsometry and (potential) energy, with energy being the component that best explains the capability of a watershed to transport debris flows. However, the morphometric indicator was found to not sufficiently explain the records of past floods in the study area. Combining the morphometric indicator with land cover indicators improved the agreement and provided a more reliable assessment of debris flow susceptibility in the study area. The analysis shows that, even if morphometric parameters identify a high disposition to the occurrence of debris flow, improving land cover can reduce the susceptibility. However, if favourable morphometric conditions are present but deterioration of the land cover in the watershed takes place, then the susceptibility to debris flow events increases. The indicator of debris flow susceptibility is useful in the identification of flood type, which is a crucial step in flood risk assessment especially in mountainous environments, and it can be used as input for prioritisation of flood risk management strategies at regional level and for the prioritisation and identification of detailed flood hazard analysis. The indicator is regional in scope, and therefore it is not intended to constitute a detailed assessment but to highlight watersheds that could potentially be more susceptible to damaging floods than others in the same region.

Quantification of flood hazard for the megacity of Lagos, Nigeria, by hydrodynamic simulation

2020 ◽  
Author(s):  
Tobias Pilz
Keyword(s):  
Flood Risk ◽  
Water Cycle ◽  
Flood Hazard ◽  
Storm Surges ◽  
Heavy Precipitation ◽  
Early Warning Systems ◽  
Data Availability ◽  
Hydrodynamic Simulation ◽  
Local Decision ◽  
The City

<p>Climate change leads to rising temperatures and therefore stimulates the water cycle. As a consequence, extreme events in rainfall and associated flooding are projected to increase in frequency and severity in many regions of the world. Especially in developing countries with high population growth and often unregulated settlement, flood risk may increase due to both increased flood hazard and enhanced exposure. One such example is the megacity of Lagos, Nigeria, belonging to the largest cities in Africa. Floods within the city are recurrent and caused by storm surges from the Atlantic, heavy precipitation, and river floods. Flood risk is an issue and even expected to increase due to enhanced extreme precipitation, sea level rise, enhances storm surges, as well as illegal settlement, poor management, insufficient or blocking of drainage channels, missing early warning systems, and insufficient data.</p><p>The aim of this study is to deliver a first quantification of flood hazard for the city of Lagos based on hydrodynamic simulation with the model TELEMAC-2D. A focus is put on the use of freely available data sources and the design of reproducible workflows in order to enable local decision-makers to individually apply and refine the established workflows. The biggest challenge is the generation of the model mesh as the basis for subsequent hydrodynamic modelling due to limited data availability and the size of the model domain (about 1000 km²).</p>

scholarly journals Mapping green infrastructure and socioeconomic indicators as a public management tool: the case of the municipalities of Andalusia (Spain)

2020 ◽  
Vol 32 (1) ◽  
Author(s):  
José Luis Caparrós Martínez ◽  
Juan Milán García ◽  
Nuria Rueda López ◽  
Jaime de Pablo Valenciano
Keyword(s):  
Green Infrastructure ◽  
Rural Areas ◽  
Urban Areas ◽  
Public Management ◽  
Local Development ◽  
Geographical Information ◽  
Management Tool ◽  
Socioeconomic Indicators ◽  
Rural And Urban Areas ◽  
Rural Municipalities

Abstract Background Green Infrastructure (GI) is defined as a strategically planned network of natural and semi-natural spaces that provide society, in both rural and urban areas, with a large number of goods and services of great value and economic importance such as clean air and water, carbon storage, pollination or protection against the effects of climate change. Traditionally, municipalities, like other territorial units, are characterized by a series of social and economic indicators that determine their degree of local development. The objective of this article is to identify and assess, through a system of indicators, what role urban and rural municipalities in Andalusia (Spain) play in the provision and reception of ecosystem services. To this end, Geographical Information System (GIS) techniques are used and a cluster analysis is carried out to contrast the results. Results Rural municipalities show the largest portion of GI area in the whole region. However, they show a low socioeconomic level, with high unemployment rates. Conclusions It can be said that the municipalities in rural areas are "ecologically" financing the entire Andalusian population. Faced with this situation, the decisions, and actions of policymakers in this region should aim at promoting measures that can restore and conserve GIs, addressing the demographic and/or socioeconomic imbalances of the region.

scholarly journals Application of GIS-Interval Rough AHP Methodology for Flood Hazard Mapping in Urban Areas

Water ◽  
2017 ◽  
Vol 9 (6) ◽  
pp. 360 ◽  
Author(s):  
Ljubomir Gigović ◽  
Dragan Pamučar ◽  
Zoran Bajić ◽  
Siniša Drobnjak
Keyword(s):  
Land Use ◽  
Urban Areas ◽  
Flood Hazard ◽  
Danube River ◽  
Geographical Information ◽  
Hazard Mapping ◽  
City Development ◽  
Ahp Method ◽  
River Bank ◽  
Extreme Flood

Floods are natural disasters with significant socio-economic consequences. Urban areas with uncontrolled urban development, rapid population growth, an unregulated municipal system and an unplanned change of land use belong to the highly sensitive areas where floods cause devastating economic and social losses. The aim of this paper is to present a reliable GIS multi-criteria methodology for hazard zones’ mapping of flood-prone areas in urban areas. The proposed methodology is based on the combined application of geographical information systems (GIS) and multi-criteria decision analysis (MCDA). The methodology considers six factors that are relevant to the hazard of flooding in urban areas: the height, slope, distance to the sewage network, the distance from the water surface, the water table and land use. The expert evaluation takes into account the nature and severity of observed criteria, and it is tested using three scenarios: the modalities of the analytic hierarchy process (AHP). The first of them uses a new approach to the exploitation of uncertainty in the application of the AHP technique, the interval rough numbers (IR’AHP). The second one uses the fuzzy technique for the exploitation of uncertainty with the AHP method (F’AHP), and the third scenario contemplates the use of the traditional (crisp) AHP method. The proposed methodology is demonstrated in Palilula Municipality, Belgrade, Serbia. In the last few decades, Palilula Municipality has been repeatedly devastated by extreme flood events. These floods severely affected the transportation networks and other infrastructure. Historical flood inundation data have been used in the validation process. The final urban flood hazard map proves a satisfactory agreement between the flood hazard zones and the spatial distribution of historical floods that happened in the last 58 years. The results indicate that the scenario in which the IR’AHP methodology is used provides the highest level of compatibility with historical data on floods. The produced map showed that the areas of very high flood hazard are located on the left Danube River bank. These areas are characterized by lowland morphology, gentle slope, sewage network, expansion of impermeable locations and intense urbanization. The proposed GIS-IR’AHP methodology and the results of this study provide a good basis for developing a system of flood hazard management in urban areas and can be successfully used for spatial city development policy.

Estimation of flood risk exposure with cross fertilization between multi-platform remote sensing and census information.

2020 ◽  
Author(s):  
Giorgio Boni ◽  
Angela Celeste Taramasso ◽  
Giorgio Roth
Keyword(s):  
Remote Sensing ◽  
Environmental Protection Agency ◽  
Flood Risk ◽  
Urban Areas ◽  
Census Data ◽  
Flood Hazard ◽  
Risk Exposure ◽  
Population Exposure ◽  
Night Time ◽  
Refresh Rate

<p>Risk exposure adjournment in flood prone areas is usually limited by the unavailability of frequently updated information about urbanization and census. This limitation is produced mainly by the complexity of the long process that lead to thematic maps compliant with common product requirements.</p><p>Therefore, the mapping of exposed elements and population does not fully exploit the potential high refresh rate typical of remote sensing. This aspect may be particularly important in developing countries, where exposure may change at sub-yearly scale.</p><p>This work explores the potential of the combination of the high refresh rate of satellite night-time light products with the high precision of urban maps and census information. Target is the evaluation of the population exposure to the flood risk in urban areas.</p><p>The idea is to calibrate nightlight vs. urban density/population relations where contemporary estimations of both variables are available. These, combined with flood hazard maps, allows the estimation of the flood risk. Results will be validated using independent estimates of the population exposed to the flood risk in the same area.</p><p>Moreover, time series of nightlight products will be used to estimate the same variables at different times, demonstrating the possibility of rapid updates.</p><p>The work is based upon DMSP night-time light series, global urban footprint (GUF) maps by the German AeroSpace Center (DLR) and census data from the Italian institute of statistics (ISTAT). The independent data for the population exposed to risk are provided by the Italian Environmental Protection Agency (ISPRA).</p>

Urban water recycling

2005 ◽  
Vol 51 (8) ◽  
pp. 83-89 ◽  
Author(s):  
T. Asano
Keyword(s):  
Water Resources ◽  
Pollution Control ◽  
Rural Areas ◽  
Urban Areas ◽  
Water Reuse ◽  
Water Cycle ◽  
Integrated Water Resources Management ◽  
Resources Management ◽  
Vital Component ◽  
Urban And Rural Areas

Increasing urbanization has resulted in an uneven distribution of population, industries, and water in urban areas; thus, imposing unprecedented pressures on water supplies and water pollution control. These pressures are exacerbated during the periods of drought and climatic uncertainties. The purpose of this paper is to summarize emergence of water reclamation, recycling and reuse as a vital component of sustainable water resources in the context of integrated water resources management in urban and rural areas. Water quality requirements and health and public acceptance issues related to water reuse are also discussed. Reclaimed water is a locally controllable water resource that exists right at the doorstep of the urban environment, where water is needed the most and priced the highest. Closing the water cycle loop not only is technically feasible in agriculture, industries, and municipalities but also makes economic sense. Society no longer has the luxury of using water only once.

scholarly journals Improving Urban Flood Mapping by Merging Synthetic Aperture Radar-Derived Flood Footprints with Flood Hazard Maps

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1577
Author(s):  
David C. Mason ◽  
John Bevington ◽  
Sarah L. Dance ◽  
Beatriz Revilla-Romero ◽  
Richard Smith ◽  
...  
Keyword(s):  
Synthetic Aperture Radar ◽  
Real Time ◽  
Rural Areas ◽  
Urban Areas ◽  
Flood Hazard ◽  
Synthetic Aperture ◽  
Hazard Maps ◽  
Urban Flood ◽  
Flood Hazard Maps ◽  
Aperture Radar

Remotely sensed flood extents obtained in near real-time can be used for emergency flood incident management and as observations for assimilation into flood forecasting models. High-resolution synthetic aperture radar (SAR) sensors have the potential to detect flood extents in urban areas through clouds during both day- and night-time. This paper considers a method for detecting flooding in urban areas by merging near real-time SAR flood extents with model-derived flood hazard maps. This allows a two-way symbiosis, whereby currently available SAR urban flood extent improves future model flood predictions, while flood hazard maps obtained after the SAR overpasses improve the SAR estimate of urban flood extents. The method estimates urban flooding using SAR backscatter only in rural areas adjacent to urban ones. It was compared to an existing method using SAR returns in both rural and urban areas. The method using SAR solely in rural areas gave an average flood detection accuracy of 94% and a false positive rate of 9% in the urban areas and was more accurate than the existing method.

Does rainfall variability explain low uptake of agricultural credit? Evidence from Ethiopia

2021 ◽  
Author(s):  
Kibrom A Abay ◽  
Bethelhem Koru ◽  
Jordan Chamberlin ◽  
Guush Berhane
Keyword(s):  
Rural Areas ◽  
Urban Areas ◽  
Credit Markets ◽  
Smallholder Farmers ◽  
Rainfall Variability ◽  
Credit Rationing ◽  
Sub Saharan Africa ◽  
Agricultural Credit ◽  
Production Risk ◽  
The Impact

Abstract Credit markets are key instruments by which liquidity-constrained smallholder farmers may finance productive investments. However, the documented low demand and uptake of agricultural credit by smallholder farmers in sub-Saharan Africa pose challenges for energizing rural transformation in the region. In this paper, we investigate the impact of rainfall uncertainty—a major source of production risk—on the uptake of credit by rural farm households in Ethiopia. We further examine whether rainfall uncertainty explains credit rationing among those households not participating in rural credit markets. We find that rainfall variability discourages the uptake of agricultural credit. We also find that rainfall variability is associated with credit risk rationing, expressed as low demand for agricultural credit. We show that our findings are robust to alternative ways of constructing rainfall variability (inter-annual or inter-seasonal) and a battery of robustness checks. For instance, we show that rainfall variability is a strong predictor of credit uptake in rural areas while less relevant in urban areas. We also document heterogeneous responses to rainfall variability; those households living in the arid and semi-arid lands of Ethiopia, which are believed to be more vulnerable to recurrent weather shocks, are more responsive to rainfall variability in terms of reduced uptake of agricultural credit. Our results highlight the impacts of uninsured production risk on the demand for agricultural credit and hence smallholder agricultural investments. Our findings suggest the importance of interventions aimed at relaxing smallholders’ credit rationing while also reducing their production risk.

Sign in / Sign up

Export Citation Format

Share Document