UAV-LiDAR observations increase the precision of urban flood modelling in Accra by detecting critical micro-topographic features

2021 ◽  
Author(s):  
Katerina Trepekli ◽  
Thomas Friborg ◽  
Thomas Balstrøm ◽  
Bjarne Fog ◽  
Albert Allotey ◽  
...  
Keyword(s):  
High Resolution ◽  
Urban Areas ◽  
Flood Control ◽  
Substantial Effect ◽  
Control Measures ◽  
Damage Potential ◽  
Urban Flood ◽  
Proactive Management ◽  
Precise Identification ◽  
Flood Prone Areas

<p>Rapidly expanding cities are exposed to higher damage potential from floods, necessitating effective proactive management using technological developments in remote sensing observations and hydrological modelling.  In this study we tested whether high resolution topographic data derived by Light and Detection Ranging (LiDAR) and Unmanned Aerial Vehicle (UAV) systems can facilitate rapid and precise identification of high-risk urban areas, at the local scale. Three flood prone areas located within the Greater Accra Metropolitan Area in Ghana were surveyed by a UAV-LiDAR system. In order to simulate a realistic flow of precipitation runoff on terrains, Digital Terrain Models (DTM) including buildings and urban features that may have a substantial effect on water flow pathways (DTMb) were generated from the UAV-LiDAR datasets. The resulting DTMbs, which had a spatial resolution of 0.3 m supplemented a satellite-based DTM of 10 m resolution covering the full catchment area of Accra, and applied to a hydrologic screening model (Arc-Malstrøm) to compare the flood simulations. The precision of the location, extent and capacity of landscape sinks were substantially improved when the DTMbs were utilized for mapping the flood propagation. The semi-low resolution DTM projected unrealistically shallower sinks, with larger extents but smaller capacities that consequently led to an overestimation of the runoff volume by 15% for a sloping site, and up to 65 % for 1st order sinks in flat terrains. The observed differences were attributed to the potential of high resolution DTMbs to detect urban manmade features like archways, boundary walls and bridges which were found to be critical in predictions of runoff’s courses, but could not be captured by the coarser DTM. Discrepancies in the derived water volumes using the satellite-based DTM vs. the UAV-LiDAR DTMbs were also traced to dynamic alterations in the geometry of streams and rivers, due to construction activities occurring in the interval between the aerial campaign and the date of acquisition of the commercially available DTM. Precise identification of urban flood prone areas can be enhanced using UAV-LiDAR systems, facilitating the design of comprehensive early flood-control measures, especially in urban settlements exposed to the adverse effects of perennial flooding. This research is funded by a grant awarded by the Danish Ministry of Foreign Affairs (Danida).</p>

scholarly journals Collaborative Development of Green Infrastructure: Urban Flood Control Measures on Small-Scale Private Lands

2021 ◽  
Vol 16 (3) ◽  
pp. 457-468
Author(s):  
Fumiko Taura ◽  
Masaki Ohme ◽  
Yukihiro Shimatani ◽  
◽  
Keyword(s):  
Green Infrastructure ◽  
Urban Areas ◽  
Flood Control ◽  
Control Measures ◽  
Japanese Culture ◽  
Small Scale ◽  
Soil Infiltration ◽  
Private Lands ◽  
Urban Flood ◽  
Runoff Reduction

Focusing on green infrastructure (GI), which utilizes nature’s diverse resources, we developed urban flood control measures on three small-scale private tracts in Tokyo and Fukuoka in Japan, experiencing high rainfall. In addition, we implemented these measures and verified the possibility of introduction. Using a target rainfall of 100 mm/h and previous rainfall data, we set our goal of reducing runoff from each site below the capacity of a public sewage pipe. Implementation was conducted by assessing the soil infiltration rate and developing and installing rain gardens and storage layers using crushed stones. These measures satisfied the initially set goals, drastically reducing runoff at all three sites. The target installation cost was set at 100,000 yen per cubic meter of runoff reduction. The target costs were met in the two Fukuoka sites but not at the Tokyo site. The key reasons were the high costs of removing non-permeable surfaces or improving the soil of compacted surfaces, which called for a process to balance the runoff reduction and cost to determine the most effective plan for implementing GI in urban areas. The development and implementation processes were conducted in collaboration with the house owners and concerned parties; the workshops produced constructive ideas being unconstrained by conventional thinking. Visitors highly appreciated ideas related to using water because the techniques were derived from the Japanese culture of lifestyle. Thus, introducing attractive and effective GI may be possible through collaboration. Additionally, sharing experiences led to the formation of new community ties, supporting post-implementation site maintenance.

Study of Urban Flood Control Planning in Taiyuan

2013 ◽  
Vol 838-841 ◽  
pp. 1709-1714
Author(s):  
Xiu Yong Yi ◽  
Yang Zhang
Keyword(s):  
Soil Conservation ◽  
Flood Control ◽  
River System ◽  
Control Measures ◽  
River Channels ◽  
Mountainous Areas ◽  
Urban Flood ◽  
Existing Problems ◽  
Downstream Area ◽  
Soil Conservation Measures

Considering topography, climate, river system, and existing problems in Taiyuan, the urban flood control planning in Taiyuan boils down to the following points: determine the flood control standard according to the size of city; study the flood alleviating measures in the upstream area; provide adequate water and soil conservation measures in the mountainous areas reduce flash floods; divert flood from mountainous areas to the downstream area instead of to the urban; improve the river channels in the urban area; provide flood detention and retarding area in the downstream area; study non-engineering flood control measures.

Flood Disaster in Japan

2007 ◽  
Vol 2 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Kazuya Inoue ◽  
Keyword(s):  
Social Factors ◽  
Urban Areas ◽  
Flood Control ◽  
Control Policy ◽  
Material Damage ◽  
Urban Flood ◽  
Flood Disasters ◽  
Development Accounting ◽  
New Type ◽  
Area Development

Progress against flood disasters since the end of Word War II has shown that although human casualties have sharply decreased, material damage has not, despite improvements in flood control facilities. This is partly due to the increased concentration of buildings, infrastructures, and other assets in urban areas. Both natural and social factors are listed, and the implementation of suitable flood control policies is indispensable to saving lives and mitigating disasters in the future. Urban flood disasters are focused as a new type disaster explained in detail, stressing a combination of structural and non-structural measures and wide-area development accounting for both rivers and their entire basins to distribute the load in terms of flood control policy.

scholarly journals Pengendalian Pemanfaatan Ruang Kawasan Terdampak Banjir Di Perkotaan Sinjai

2021 ◽  
Vol 1 (2) ◽  
pp. 147-164
Author(s):  
Muhammad Muhammad Afandi Naser ◽  
Murshal Manaf ◽  
Tri Budiharto
Keyword(s):  
Spatial Pattern ◽  
Urban Areas ◽  
Flood Control ◽  
Flood Hazard ◽  
Descriptive Analysis ◽  
Disaster Mitigation ◽  
Qualitative Descriptive ◽  
Spatial Use ◽  
High Flood ◽  
Flood Prone Areas

Abstract. This study aims to explain the characteristics of flood-affected areas, in order to analyze land suitability and spatial use in flood-affected areas and to formulate the concept of controlling the spatial use of flood-affected areas. This research is qualitative-quantitative with the analysis techniques used are scoring analysis, superimpose analysis, qualitative descriptive analysis and space envelope analysis. The results show that there are three classifications of flood hazard, namely low, medium and high, where in the high flood-prone areas in Sinjai city there are five villages, namely Balangnipa Village, Biringere Village, Bongki Village, Lappa Village and Samataring Village. The results of the second research objective were obtained from the overlay prone to flooding and the spatial pattern of the Sinjai urban RDTR, where the dominant spatial pattern of high flood prone areas is in the housing zone which covers an area of ​​564,185 hectares. The direction of the strategic concept based on three classifications of flood hazard in Sinjai urban areas is proposed in the form of disaster mitigation in the form of recommendations for flood control in accordance with the characteristics of flood-prone areas, and in controlling spatial use in the form of zoning regulations and permit proposals at the research location granting land use permits for each area prone to high, medium and low flood disasters.   Abstrak. Penelitian ini bertujuan untuk menerangkan karakteristik kawasan terdampak banjir, guna menganalisis kesesuaian lahan dan pemanfaatan ruang pada kawasan terdampak banjir dan merumuskan konsep pengendalian pemanfaatan ruang kawasan terdampak banjir. Penelitian ini bersifat kualitatif-kuantitatif dengan teknik analisis yang digunakan adalah analisis skoring, analisis superimpose, analisis deskriptif kualitatif dan analisis amplop ruang. Hasil penelitian diketahui bahwa terdapat tiga klasifikasi kerawanan banjir yaitu rendah, sedang dan tinggi yang dimana pada kawasan rawan banjir tinggi di perkotaan Sinjai terdapat di lima kelurahan yaitu Kelurahan Balangnipa, Kelurahan Biringere, Kelurahan Bongki, Kelurahan Lappa dan Kelurahan Samataring. Adapun hasil tujuan penelitian kedua yang didapat dari overlaynya rawan banjir dan pola ruang RDTR perkotaan Sinjai, dimana yang berdominan pada pola ruang kawasan rawan banjir tinggi terdapat di zona perumahan yang luasnya sebesar 564.185 Ha. Arahan konsep strategi berasarkan tiga klasifikasi kerawanan banjir di kawasan perkotaan Sinjai diusulkan dalam bentuk mitigasi bencana berupa rekomendasi pengendalian banjir yang sesuai dengan karakteristik pada kawasan rawan banjir, dan pada pengendalian pemafaatan ruang berupa peraturan zonasi dan usulan perizinan di lokasi penelitian dapat disimpulkan bahwa  terdapat perbedaan perilaku pemberian perizinan penggunaan lahan pada setiap kawasan rawan bencana banjir tinggi, sedang maupun rendah.

Planning and Design of Urban Flood Control Measures: Assessing Effects Combination

2009 ◽  
Vol 135 (3) ◽  
pp. 100-109 ◽  
Author(s):  
Marcelo Gomes Miguez ◽  
Flavio Cesar Borba Mascarenhas ◽  
Luiz Paulo Canedo de Magalhães ◽  
Carlos Fabiano Vellozo D’Alterio
Keyword(s):  
Flood Control ◽  
Control Measures ◽  
Urban Flood ◽  
Planning And Design

scholarly journals Modelling floods in urban areas and representation of buildings with a method based on adjusted conveyance and storage characteristics

2012 ◽  
Vol 15 (4) ◽  
pp. 1150-1168 ◽  
Author(s):  
Zoran Vojinovic ◽  
Solomon Seyoum ◽  
Mwanaisha H. Salum ◽  
Roland K. Price ◽  
Ahmad K. Fikri ◽  
...  
Keyword(s):  
High Resolution ◽  
Urban Areas ◽  
Real Life ◽  
Building Blocks ◽  
Urban Flood ◽  
Coarse Resolution ◽  
Resolution Model ◽  
Inertia Model ◽  
Depth Relationship

The present paper reviews several approaches that can be used in capturing urban features in coarse resolution two-dimensional (2D) models and it demonstrates the effectiveness of a new approach against the straightforward 2D modelling approach on a hypothetical and a real-life case study work. The case study work addresses the use of coarse grid resolutions in 2D non-inertia models. The 2D non-inertia model used solves continuity and momentum equations over the cells of the coarse model while taking the minimum elevation as a surface level. The volume stored in every cell is calculated as a volume-depth relationship. In order to replicate restriction in conveyances in x–y directions of fine resolution models due to building blocks, the friction values of the coarse-resolution model are adjusted to match the results of the high-resolution model. The work presented in this paper shows the possibility of applying a 2D non-inertia model more effectively in urban flood modelling applications whilst still making use of the high resolution of topographic data that can nowadays be easily acquired.

scholarly journals Urban Flood Prevention and Early Warning System in Jinan City

2018 ◽  
Vol 38 ◽  
pp. 03047
Author(s):  
Shiyuan Feng ◽  
Qingguo Li
Keyword(s):  
Early Warning ◽  
Urban Areas ◽  
Flood Control ◽  
Comprehensive Evaluation ◽  
Warning System ◽  
Fuzzy Comprehensive Evaluation ◽  
Urban Flood ◽  
Evaluation Indexes ◽  
Jinan City ◽  
High Standards

The system construction of urban flood control and disaster reduction in China is facing pressure and challenge from new urban water disaster. Under the circumstances that it is difficult to build high standards of flood protection engineering measures in urban areas, it is particularly important to carry out urban flood early warning. In Jinan City, a representative inland area, based on the index system of early warning of flood in Jinan urban area, the method of fuzzy comprehensive evaluation was adopted to evaluate the level of early warning. Based on the cumulative rainfall of 3 hours, the CAflood simulation results based on cellular automaton model of urban flooding were used as evaluation indexes to realize the accuracy and integration of urban flood control early warning.

scholarly journals Effectivity of kiwi and sukamahi dam on jakarta flood control

2018 ◽  
Vol 7 (3.29) ◽  
pp. 134
Author(s):  
Airlangga Mardjono ◽  
Pitojo Tri Juwon ◽  
Lily Montarcih Limantara ◽  
Ery Suhartan
Keyword(s):  
Urban Areas ◽  
Flood Control ◽  
Residential Areas ◽  
Final Test ◽  
Flood Simulation ◽  
Flood Volume ◽  
Huge Impact ◽  
Level Method ◽  
The 19Th Century ◽  
Flood Prone Areas

Various infrastructures such as flood levees, dams and reservoirs of flood control began to be developed in the 19th century to the 20th century. These buildings are very effective in controlling the flow of rivers and preventing flood waters from entering residential areas located in flood-prone areas. Flooding in urban areas has a huge impact, covering all aspects of life as well as on the landscape. Ciliwung is one of the rivers that allegedly contributed to the problem of flood in Jakarta, various engineering done on Ciliwung to help control flooding in Jakarta. One of the engineering done is the construction plan of Ciawi Reservoir and Sukamahi Reservoir. In this research, the writer performed the flood calculation using Nakayasu while method of flooding is calculated using the pool routine level method. The effectiveness of these two reservoirs can be determined by simulating floods in the existing condition and comparing them with the flood simulation after the construction of the dam. The final test of this research is to determine the effectiveness level of Ciawi and Sukamahi dam infrastructure in reducing flood volume in Jakarta.  

Comprehensive flood control involving citizens in a Japanese watershed

2013 ◽  
Vol 68 (4) ◽  
pp. 791-798 ◽  
Author(s):  
Sampei Yamashita ◽  
Yukihiro Shimatani ◽  
Ryoichi Watanabe ◽  
Toshiyuki Moriyama ◽  
Tomoko Minagawa ◽  
...  
Keyword(s):  
Urban Areas ◽  
Heavy Rainfall ◽  
Flood Control ◽  
Drainage System ◽  
Flood Disaster ◽  
Control Measures ◽  
The City

In July 2009, the city of Fukuoka, Japan experienced a flood disaster along the Hii River, which runs through densely populated, concrete-covered areas of the city. The drainage system was overwhelmed and the river overflowed due to heavy rainfall and rapid runoff. The event led citizens in its watershed to plan and implement comprehensive flood control. The plan aims not only to mitigate floods but also to revitalize the river environment and populated communities in urban areas. This study reports the activities led by the citizens. They organized and carried out civic forums, workshops, and fieldwork to share views as to how the flood disaster was caused, how floods in the watershed should be controlled, and how the river environment should be rehabilitated. This study illuminates how people, including the flood victims and municipal engineers, can change drastically and communicate effectively in the course of discussing and implementing the comprehensive flood control measures.

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