• Ecology and Resilient Infrastructure
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• v.10 no.2
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• pp.40-49
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• 2023

To reduce the damage of extreme flooding caused by climate change and to create flood mitigation sections in a nature-friendly riparian area, it is necessary to restore the floodplain area by referring to the past floodplain section of the current inland waterfront area before the levee was built. This study proposed a method of selecting a location for floodplain restoration using old maps of the Geum River study section and analyzed the effect of flood level reduction through unsteady flow numerical simulations using the floodplain as a flood mitigation space. As a result of analyzing changes in the river areas using old maps, the river section was estimated to gradually reduce by 27.8% (1,059,380 m²) in 2020 compared to 1919, and it was found to have an effective storage capacity of 2,200,868 m³ when restored to offline storage. The flood level and discharge control effects analyzed based on HEC-RAS unsteady flow simulation were 16 cm and 219.01 m³/s, respectively, in the downstream cross-section. In the numerical simulation in this paper, the flood mitigation space was applied as an offline reservoir. The effect of reducing the flood level may differ if levee retreat/relocation is applied.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.962-964
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• 2003

In 2002 Thailand was faced with severe flooding in the North, Northeast and Central parts of the country caused by heavy rainfall of the monsoonal depression which brought about significant damages. According to the report by the Ministry of Interior and the Ministry of Agricultural and Co-operatives, the total damages were estimated to be about 6 billion bath. More than 850,000 farmers and 10 million livestock were effected. An area of 1,450,000 ha of farmland in 59 Provinces were put under water for a prolonged period. Satellite imageries were employed for mapping and monitoring the flood-inundated areas, flood damage assessment, flood hazard zoning and post-flood survey of river configuration and protection works. By integrating satellite data with other updated spatial and non-spatial data, likely flood zones can be predicted beforehand. Some examples of satellite data application to flood dis aster mitigation in Thailand during 2002 using mostly Radarsat-1 data and Landsat-7 data were illustrated and discussed in the paper. The results showed that satellite data can clearly identify and give information on the status, flooding period, boundary and damage of flooding. For comprehensive flood mitigation planning, other geo-informatic data, such as the elevation of topography, hydrological data need to be integrated. Ground truth data of the watershed area, including the water level, velocity, drainage pattern and direction were also useful for flood forecasting in the future.

• KCID journal
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• v.17 no.2
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• pp.105-114
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• 2010

Tidal land reclamation provided water resources and land for agriculture and contributed stable crop production. However, climate change by global warming disrupts the hydrologic circulatory system of the earth resulting in sea level rise and more frequent flood for reclaimed arable land. Recently, Suyu reclaimed paddy field in Jindo-gun experienced prolonged inundation after heavy rainfall and there is a growing risk of flood damage. Onsite survey and flood analysis using GATE_Pro model of Korea Rural Corporation were conducted to investigate causes of flooding. To perform the analysis, input data such as inflow hydrograph, the lowest elevation of paddy field, neap tide level, management level of Gunnae estuary lake at the time of the flood were collected. Flood analysis confirmed that current drainage facilities are not enough to prevent 20year return period flood. The result of analysis showed flooding more than 24hours. Therefore, flood mitigation alternatives such as sluice gate expansion, installation drainage pumping station, refill paddy land, and catch canal were studied. Replacing drainage culvert of Suyu dike to sluice gate and installing drainage pumping station at the Gunne lake were identified as an effective flood control measures. Furthermore, TM/TC (SCADA) system and expert for gate management are required for the better management of drainage for estuary dam and flood mitigation.

• Magazine of the Korean Society of Hazard Mitigation
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• v.4 no.3 s.14
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• pp.90-103
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• 2004

• Journal of Korea Water Resources Association
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• v.43 no.5
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• pp.495-505
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• 2010

The integrated basin-wide flood mitigation planning has a numerous individual proposals with different characteristics. So, it makes difficult to develop the optimal alternative that combines such elements. To develop the optimal alternative, it's necessary not only to assess the flood damage but also to define a tolerable degree of damage. Such a definition is made in a way, dubbed the 'social consensus' in a broad sense; but initially, it requires the analysis of the economic efficiency within a scope, which is technically achievable. This study aims to propose the alternatives development method so that the combination of the individual proposals could be economically efficient. To this end, this study defined the flood mitigation projects as the economic production activities carried out by inputs and outputs, and proposed the optimal project size as the principle of developing alternatives. This study may have the worth in improving the alternatives development method by considering the optimal project scale from the economic viewpoint while the existing method depending on engineering aspect. Such approach is expected to correspond to the current government's policy that avoids the passive flood mitigation focused on channel-wide planning but pursues the basin-wide flood mitigation planning focusing on damaged area, thereby provide efficient tools to come up with the solution.

• Journal of Environmental Policy
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• v.11 no.4
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• pp.59-84
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• 2012

'Planning researchers' believe that losses from floods can be reduced if governments address this issue and adopt appropriate policies in their plan. As a starting point for examining this idea, this research assessed the ability of local government to incorporate flood mitigation policies in their local comprehensive plans using plan quality evaluation methodology. This study analyzed 53 local comprehensive plans in Florida against the protocol developed by including key flood mitigation policies. While flood mitigation through land use management tools, such as permitted land use in floodplain areas and wetland permit, gained widespread acceptance at the local level in Florida, incentive based tools/taxing tools and acquisition tools were rarely adopted. Study results show that 53 local plans in the sample received a mean score for total flood mitigation policy quality of 38.55, which represents 35.69 % of the total possible points. These findings indicate that there is still considerable room for improvement by local governments on flood issues. The scores of local plans varied widely, with coastal communities receiving significantly higher scores than non-coastal communities. Because the concept of the plan quality and its methodology offer an objective and straightforward tool for studying plan quality and guiding plan preparation, they can be applied to various environmental and hazard issues in Korea.

• Economic and Environmental Geology
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• v.56 no.1
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• pp.65-73
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• 2023

As one of the most vulnerable countries to floods, there should be an increased necessity for accurate and reliable flood forecasting in Indonesia. Therefore, a new prediction model using a machine learning algorithm is proposed to provide daily flood prediction in Indonesia. Data crawling was conducted to obtain daily rainfall, streamflow, land cover, and flood data from 2008 to 2021. The model was built using a Random Forest (RF) algorithm for classification to predict future floods by inputting three days of rainfall rate, forest ratio, and stream flow. The accuracy, specificity, precision, recall, and F1-score on the test dataset using the RF algorithm are approximately 94.93%, 68.24%, 94.34%, 99.97%, and 97.08%, respectively. Moreover, the AUC (Area Under the Curve) of the ROC (Receiver Operating Characteristics) curve results in 71%. The objective of this research is providing a model that predicts flood events accurately in Indonesian regions 3 months prior the day of flood. As a trial, we used the month of June 2022 and the model predicted the flood events accurately. The result of prediction is then published to the website as a warning system as a form of flood mitigation.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.3 s.10
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• pp.165-171
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• 2003

An abnormal storm by the typhoon of RUSA in 2002th year was broken out with tremendous flood demages and inundations on the basin of Chogangcheon located in the upper middle part of Guem river's upstream. This flood could not be engaged because it was so big that the stage engaging Songcheon station stuck to Songcheon bridge was destroyed by submerging. In this study the quantity of the flood was calculated by use of Manning's equation and suitable roughness coefficient was suggested.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.6
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• pp.721-733
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• 2023

As the frequency of extreme rainfall events increase due to climate change, climate change adaptation measures have been proposed by the central and local governments. In order to reduce flood damage in urban areas, various flood response policies, such as low impact development techniques and enhancement of the capacity of rainwater drainage networks, have been proposed. When these policies are established, regional characteristics and policy-effectiveness from the cost-benefit perspective must be considered for the flood mitigation measures. In this study, capacity enhancement of rainwater pipe networks and low impact development techniques including green roof and permeable pavement techniques are selected. And the flood reduction effect of the target watershed, Gwanak campus of Seoul National University, was analyzed using SWMM model which is an urban runoff simulation model. In addition, along with the quantified urban flooding reduction outputs, construction and operation costs for various policy scenarios were calculated so that cost-benefit analyses were conducted to analyze the effectiveness of the applied policy scenarios. As a result of cost-benefit analysis, a policy that adopts both permeable pavement and rainwater pipe expansion was selected as the best cost-effective scenario for flood mitigation. The research methodology, proposed in this study, is expected to be utilized for decision-making in the planning stage for flood mitigation measures for each region.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.1 s.12
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• pp.33-40
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• 2004

The objective of this study is to develop single dam operation models for flood control using Fuzzy control technique, which can improve flood controllability. We set control rules by water level and inflow, and developed three models Fuzzy I, II, III according to rule to decide outflow. Fuzzy I model consists of six rules considering only flood control and Fuzzy II model considers the effect of water use by increasing water level at the end of flood control period as well as flood control during the same period. Finally, Fuzzy m is an adaptive model designed to perform multipurpose dam operation for both flood control and water use simultaneously based on a control rules.