Stream Flood Research Articles

Development of measured hydrodynamic information-based flood early warning system for small streams

In general, small stream basins, characterized by narrow channels and steep slopes, face heightened vulnerability to climate change-induced flooding, posing challenges for evacuation procedures. With the increasing intensity of floods and typhoons in recent years, urgent measures are necessary to mitigate damage in such areas. This research endeavors to address these challenges by developing a novel small stream flood early warning system (SSFEWS) tailored to small streams and piloting its application. The proposed system integrates real-time hydrodynamic data collection, flood probability forecasting, and proactive warning issuance through an amalgamation of IoT-based sensor networks, statistical models leveraging measurement data, a robust constrained nonlinear optimization algorithm (RCNOA), and four-parameter logistic method (4PL). Moreover, system accuracy and reliability are enhanced by an automated iterative process that continuously refines forecasting model parameters via a user-defined rainfall-discharge nomograph and rating curve using RCNOA and 4PL. The developed SSFEWS is expected to contribute to the safety of the community as well as prevent possible small stream-related casualties by enabling efficient disaster response.© 2024 Elsevier Ltd. All rights reserved.

Sources of limestone dissolution from surface water-groundwater interaction in the carbonate critical zone

Dissolution of carbonate minerals in karst aquifers has long been recognized to result from recharge of surface water undersaturated with respect to calcite from carbonic acid produced by hydration of dissolved atmospheric and respired CO2. However, dissolution also results from additional acids produced by reactions of redox sensitive solutes in the subsurface, which may represent a source of CO2 to Earth's atmosphere. Because the magnitude of dissolution by these additional acids is poorly constrained, we compare here fractions of dissolution from initial surface water undersaturation and subsurface redox reactions. Estimates are based on chemical mixing and geochemical (PHREEQC) modeling of time series measurements of water compositions at a spring vent that receives surface water during stream flooding and a stream sink-rise system in north-central Florida. During a single spring reversal, 9.2 × 105 kg of limestone dissolved. At the stream sink-rise system, where subsurface residence times are shorter than during the spring reversal, both limestone dissolution (102–104 kg) and precipitation (102–105 kg) occur as water flows through the conduits with residence times ranging from 10 to 70 h. At both sites, maximum calcite dissolution rates of ∼10 μM hr−1 occurs at subsurface residence times between 30 and 50 h. For subsurface residence time > ∼20–60 h, the models indicate that production of additional acid in the subsurface is required for ∼53 ± 7% of dissolution. Oxidation of organic carbon, ammonium, pyrite, iron, and/or manganese produce sufficient acid for additional dissolution, but dissolved oxygen is insufficient for these reactions, indicating some acidity is generated under anerobic conditions. Dissolution caused by subsurface reactions in our samples represents mobilization of 20 × 104-30 × 104 kg of CO2 via remineralization of organic carbon or carbonate dissolution by nitric and sulfuric acids. Acid produced by subsurface redox reactions during surface water-groundwater interactions, including non‑carbonic acids, are important in conduit development and carbon cycling in the carbonate critical zone.

Movement and habitat shift responses of juvenile Atlantic Salmon (Salmo salar) to annually permanent stream flooding.

Reservoir formation in a river system changes a lotic environment to more lacustrine conditions, with impacts throughout the ecosystem. In this study, a river reach containing typical salmonid riffle/run habitat was flooded to create a large, deep pool from June to September in each of 3 years. We test the hypothesis that juvenile Atlantic salmon (Salmo salar) with their preference for run/riffle habitats will respond to the transformation to a lentic environment by moving into adjacent lotic environments. Movements of juvenile Atlantic salmon were monitored using a combination of biotelemetry (radio- and passive integrated transponder-tagging) and electrofishing. Results showed that no tracked fish moved away from the created pool habitat. Mass-specific growth rates showed the created pool habitat resulted in net growth of juveniles. The results confirm that fish may not immediately (i.e., at least for an approximate 2 months) respond to rapid, large-scale habitat alterations by moving to find similar habitat conditions outside the altered habitat. This is most probably related to plasticity of behavior and habitat use, and no change in biological conditions to a point that would negatively impact fish growth and survival, for example food availability, competition, or predation. The results also support the hypothesis that the relative importance of physical habitat variables is not universal among streams and populations, therefore limiting the value of applying standard habitat suitability criteria and use.

Assessing the Suitability of the Flood Defense Policy of Republic of Korea for Risk Reduction in Local Rivers

This study examines whether the fluvial flood defense system of Korea is appropriate for risk reduction. Using spatial socioeconomic data and remote sensing, we estimated the potential economic damage that can be caused by the flooding of local streams and rivers along the Nakdong River (the longest river in Korea). For the analysis, a river risk map including return periods (50, 80, 100, and 200 years) and spatial inventories (residential, agricultural, industrial assets, and human lives) was employed to determine flood-prone areas and assess the damage within the inundation areas. A quantitative flood analysis was conducted using an object-based method to estimate the expected annual damage. We then compared the estimated damage for each tributary within the designed return periods and found no correlation. Numerous tributaries with low-defense targets were considered high-risk, while those with high-defense targets were assessed as low-risk. The dataset used in this study covered four damage categories. Among them, flood damage to residential assets appeared to have the highest value, whereas flood damage to industrial assets had the lowest value. The results demonstrate that the Korean government needs to tailor its flood defense policy based on quantitative risk assessments to effectively manage flood risks, especially given the increasing risk of climate change.

GIS-Based RUSLE Reservoir Sedimentation Estimates: Temporally Variable C-Factors, Sediment Delivery Ratio, and Adjustment for Stream Channel and Bank Sediment Sources

The empirical Revised Universal Soil Loss Equation (RUSLE) has been adapted to geographical information system (GIS) frameworks to study the spatial variability of soil erosion across landscapes and has also been used to estimate reservoir sedimentation. The literature presents contradictory results about the efficacy of using RUSLE in a GIS context for quantifying reservoir sedimentation, requiring further evaluation and validation of its estimates relative to measured reservoir sedimentation. Our primary objective was to determine if these contradictory results may be a function of the RUSLE’s inability to account for sediments derived from gullies, stream channels, or stream banks; the temporal variability of some of RUSLE’s empirically based factors such as the land cover/land management (C-) factor; and in some model renditions, the choice of value for the sediment delivery ratio (SDR). The usefulness of adjusting these estimates using a regional representative value of gully/stream bank sediment contributions was also assessed. High-spatial horizontal resolution (2 m) digital elevation models (DEMs) for 12 watersheds were used together with C-factor data for five representative years in a GIS-based RUSLE model that incorporates SDR within a sediment routing routine to study the impacts of choice of C-factor and SDR on reservoir sedimentation estimates. Choice of image date for developing C-factors was found to impact reservoir estimates. We also found that the value of SDR for some of the study watersheds would have to be unrealistically small to produce sedimentation estimates comparable to measured values. Estimates of reservoir sedimentation were comparable to measured data for 5 of the 12 watersheds, when the regionally based adjustment for gully/stream bank contributions was applied. However, differences remained large for the remaining seven watersheds. Statistical analysis revealed that certain combinations of geomorphic, pedologic, or topographic variables could be used to predict the degree of sediment underestimation with a significant and high level of correlation (0.72 < R2 ≤ 0.99; p-value < 0.05). Our findings indicate that the level of agreement between GIS-based RUSLE estimates of reservoir sedimentation and measured values is a function of watershed characteristics; for example, the area-weighted soil erodibility (K-) factor of the soils within the watershed and stream channels, the stream entrenchment ratio and bank full depth, the percentage of the stream corridor having slopes ≥ 21°, and the width of the stream flood way as a percentage of the watershed area. Within the context of GIS, these metrics are easily obtained from digital elevation models and publicly available soils data and may be useful in prioritizing reservoirs’ assessments for function and safety.

Tide-modulated river discharge division in the Ganges-Brahmaputra-Meghna delta channel network, Bangladesh

Study RegionThe Ganges-Brahmaputra-Meghna (GBM) delta in Bangladesh Study FocusThe flow distribution in a deltaic channel network is complicated by tidal wave propagation. We use a 2DH numerical model to investigate the variability of the tide-modulated seasonal, subtidal, intratidal and residual divided discharges. New Hydrological InsightsSimulations show that the divided subtidal discharges and correlated subtidal water levels display remarkable fortnightly fluctuations in dry months, whereas they are heavily distorted by the rapid rising & falling limbs of main stream flood waves in wet months. A subtidal water circulation that net water is transported from the tributaries to the main stream maintains at lower upstream discharges but is reversed by larger upstream discharges. With a series of increasing upstream riverine discharges routing downstream, the subtidal inflows experience a phase shift in the fortnightly cycles, in which the inflow peaks gradually move from spring tide to neap tide; moreover, the residual inflows demonstrate a non-monotonic variability, i.e. enlargements to the river-only case occur at two particular upstream discharges, compared to the reduced residual inflows at the majority of upstream discharges. These characteristic processes are explained by the mean amplitudes and phase relationships of tidal species (D1,D2,D4,D1/14) and the increasing dominance of river discharge over tidal wave. Our findings deepen the understandings of the complex nonlinear river-tide interactions in a deltaic channel network.

Downstream changes in floodplain sedimentation and their effects on channel avulsion in stream-dominated alluvial fans: The Cretaceous Duwon Formation in the southern Korean Peninsula

Stream-dominated alluvial fans are formed by the periodic channel avulsion running on their surfaces and are characterized by the downstream changes in hydrodynamics of stream flows and flood frequency. The spatial variations in hydrodynamics also control the sedimentation on the floodplain, which is important for sediment dispersal patterns on the stream-dominated alluvial fans as they feed back into channel avulsion processes. To understand the influence of downstream changes in hydrodynamics on the floodplain sedimentation and associated channel avulsion processes, we studied the Cretaceous Duwon Formation in the southern part of the Korean Peninsula. The Duwon Formation unconformably overlies the Paleoproterozoic basements and consists of gravelly braided stream deposits (FA-1), sandy braided stream deposits (FA-2), and calcretes-bearing floodplain deposits (FA-3). Close to the basements, FA-1 shows the radial paleoflow patterns, and the size of sediments and the ratio of channel to floodplain deposits decrease downstream over a relatively short distance (<7 km). This indicates that the Duwon Formation was deposited in the stream-dominated alluvial fans under arid to semi-arid climatic conditions, which can be classified into the proximal, medial, and distal zones.In the medial zone, the floodplain deposits are composed of the underlying, purple-colored sandstones and the overlying, compensational stacked crevasse channel and splay deposits (ca. 19 m thick) with the unsystematic paleoflow directions, finally overlain by the sandy braided stream deposits. In contrast, in the distal zone, the floodplain fines are composed of homogeneous clay and silt with calcretes and vegetation traces. These floodplain fines are interbedded with and overlain by the progradational stacked, coarsening- and thickening-upward trending, crevasse channel and splay deposits (ca. 18 m thick) with the constant paleoflow directions to those of the overlying sandy braided stream deposits. In the medial zone, a relatively large volume of discharge of the stream floods resulted in the frequent overbank flooding via the multiple breaching points and the concomitant growth of alluvial ridges by the combined effects of in-channel bed aggradation and compensational stacked crevasse channel and splay deposits resulted in a shift in the flow pathway of the sandy braided streams. In the distal zone, the floodplain fines containing calcretes and vegetation traces suggest the longer periods of non-deposition, providing sufficient time for the vegetation development. Once the channel levees collapsed, the vegetated channel levees stabilized the breaching point, and the breaching point progressively incised by the multiple flooding events, causing susceptibility to overbank flooding. Crevasse channel flows via the breaching point and associated overbank floodwaters led to a continuous supply of the coarse-grained sediments stacking on the cohesive, vegetated floodplain fines, with an increase in the cross-floodplain topographic gradient. As a result, crevasse channels were able to advance the distal floodplains, resulting in the development of progradational stacking pattern. With the cross-floodplain topographic gradient, the deposition of these erodible overbank flooding sediments on the cohesive, vegetated floodplain fines provided an alternative route for the parent channel, resulting in channel avulsion. Thus, this study suggests that downstream changes in hydrodynamics and associated floodplain sedimentation are important for channel avulsion and hence control the sediment dispersal patterns of coarse-grained sediments on the stream-dominated alluvial fans.

Evaluating Urban Stream Flooding with Machine Learning, LiDAR, and 3D Modeling

Flooding in urban streams can occur suddenly and cause major environmental and infrastructure destruction. Due to the high amounts of impervious surfaces in urban watersheds, runoff from precipitation events can cause a rapid increase in stream water levels, leading to flooding. With increasing urbanization, it is critical to understand how urban stream channels will respond to precipitation events to prevent catastrophic flooding. This study uses the Prophet time series machine learning algorithm to forecast hourly changes in water level in an urban stream, Hunnicutt Creek, Clemson, South Carolina (SC), USA. Machine learning was highly accurate in predicting changes in water level for five locations along the stream with R2 values greater than 0.9. Yet, it can be challenging to understand how these water level prediction values will translate to water volume in the stream channel. Therefore, this study collected terrestrial Light Detection and Ranging (LiDAR) data for Hunnicutt Creek to model these areas in 3D to illustrate how the predicted changes in water levels correspond to changes in water levels in the stream channel. The predicted water levels were also used to calculate upstream flood volumes to provide further context for how small changes in the water level correspond to changes in the stream channel. Overall, the methodology determined that the areas of Hunnicutt Creek with more urban impacts experience larger rises in stream levels and greater volumes of upstream water during storm events. Together, this innovative methodology combining machine learning, terrestrial LiDAR, 3D modeling, and volume calculations provides new techniques to understand flood-prone areas in urban stream environments.

River Flood Characteristics Along the Canal Area Effected By Hanzhuang Canal Jacking

In this paper, flood characteristics along the canal area effected by Hanzhuang Canal jacking are studied. By coupling the rainfall runoff (NAM) model with the hydrodynamic (HD) model, a 1-D hydrologic-hydrodynamic coupling model was built. On the basis of parameter calibration and model validation, different flood simulation schemes are drawn up, and the influence range of Hanzhuang Canal jacking and the flood characteristics of tributaries affected by Hanzhuang Canal jacking are analyzed respectively. The results show that with the increasing discharge of Hanzhuang Canal, the water level of Hanzhuang canal rises gradually, the main stream flood flows upstream along the tributaries, the water level of the tributaries rises gradually, and the risk of flood disasters increases. Among the tributaries, Taogou River is most affected by Hanzhuang Canal jacking and has the highest risk of flood disaster, followed by Dasha River, Dasha River Floodway and Sizhi Ditch. The results also show that the backwater of Hanzhuang Canal on the tributaries is mainly reflected in the influence on the upstream flood water level process, but has little or no influence on the flood discharge process, which can provide a reference for regional flood control and scheduling department.

HEC-RAS 2B Modeli Kullanılarak Yazılıkaya Deresi (Nallıhan Ankara) Sel Tehlike Haritalarının Hazırlanması ve Sel Kontrol Yapısının Etkinliği

Sel, aşırı yağışlar ve karların hızla erimesi gibi meteorolojik koşulların değişim göstermesi sonucu oluşan doğa kaynaklı afetlerden birisidir. Bölgenin topoğrafyası, jeolojik yapısı, iklim koşulları, akarsu veya derelerin doğal yapılarında meydana gelen bozulmalar ve kontrolsüz kentleşme gibi faktörler sellerin oluşumunda büyük rol oynamaktadır. Bu çalışma kapsamında, Ankara İli Nallıhan İlçesi sınırları içerisinde bulunan ve Yazılıkaya deresinin su toplama havzası sınırları içerinde sel tehlikesine karşı dere içi ıslah çalışmaları yapılmış, 78.8 hektar (Ha) alan içerisinde bir adet harçlı ıslah sekisi projelendirilmesi ve uygulaması gerçekleştirilmiştir. Ankara İli Nallıhan İlçesi Yazılıkaya deresi dere içi ıslah çalışmasında elde edilen veriler (dere haritaları, debileri ve sanat yapısı en kesitleri) ve DSİ Sentetik Yöntemi ile Q10 ve Q100 debi değerleri kullanılarak HEC-RAS (Hydrologic Engineering Centers River Analysis System) programı yardımıyla Yazılıkaya deresinde iki boyutlu sel modellemesi yapılmıştır. Yapılan analizler sonucunda Yazılıkaya deresi üzerinde yapılan harçlı ıslah sekisinin, olası şiddetli ve anlık yağışlarda Q10 ve Q100 debi değerlerinin kullanıldığı analizlerde suyun hızı sırası ile yapısız durumda sırası ile 2 m/s – 3.2 m/s iken yapı yapıldıktan sonra 0.5 m/s – 0.75 m/s değerlerine düştüğü gözlemlenmiştir. Sırasıyla Q10 ve Q100 debi değerlerine göre yapılan yerleşim yerlerindeki su derinliği analizlerinde, harçlı ıslah sekisi yapımı tamamlandıktan sonra 2 cm (Q10) ve 8 cm (Q100) kadar su azalmalarının olduğu hesaplanmıştır. Genel olarak bu çalışmada, yukarı havza sel kontrol yapılarının (harçlı ıslah sekisi) yağış sularının akış rejimlerinin düzenlenmesinde (su enerjisi, hızı, derinliği, vb.), nüfusun yoğunlaştığı yerleşim yerlerinde ve karayolunda sel tehlikesine karşı etkileri araştırılmıştır.

The ‘Deluge’ of 25 October 1822 in Genoa, Italy

The ‘Deluge’ of 25 October 1822 in Genoa, Italy

Empirical roughness coefficients for moderate floods in an open conduit cave: Fullers stream canyon, Culverson Creek Cave System, West Virginia

Open conduit modeling of cave stream floods can yield useful information about water velocities and shear stresses, which can in turn be used to estimate sediment transport capabilities. All such calculations require roughness coefficients for estimating energy losses and a priori knowledge of either discharge or flow depths to set model boundary conditions. However, the difficulties associated with observing in-cave floods generally preclude measuring discharge; roughness coefficients must be assumed based on channel properties. To overcome these challenges, we monitored stream flow depths in Fullers Cave, Greenbrier County, West Virginia using pressure transducers, and simultaneously measured stage and discharge in a karst window immediately upstream of the cave. Five pressure transducers were deployed opportunistically along a 93-meter-long reach in a 10+ meter high canyon averaging 1.5 to 3 meters wide. Stage-discharge relationships were determined for the karst window using an electromagnetic flow meter for floods with peak discharges of 1.66 m3 s-1 or less. The collected data was used to obtain the empirical Manning’s n roughness values, head losses, and energy gradients. Calculated floodwater velocities are comparable to values obtained from scallops on passage walls. Major energy losses were observed where breakdown partially occludes the passage. At peak flow, Manning n values average 0.053 for reaches typified as cobble-floored canyons, but n was 0.069 in the breakdown reach. Roughness values declined exponentially with increasing discharge, but friction slopes calculated using head losses show more complex relationships with discharge. Notably, n values back calculated using bed gradients differ from those calculated using measured head losses by as little as 12%, so the use of bed gradients in roughness estimations will generally yield reasonable approximations of flow conditions. Fullers Cave experiences significantly larger open conduit floods than we observed, so additional work is needed to estimate roughness coefficients for higher discharges. Our empirical roughness coefficients can be applied to similar cave passages in other caves and contexts, including modeling slot canyon-like channels, and our methods demonstrate a technique for measuring hard to obtain data. The addition of data for open conduit conduits significantly expands the range of environments that can be modeled using empirical data beyond pipe-full caves. Applications include studying flooding, sediment transport, and bedrock erosion process. All of these topics will be addressed in Fullers in the future.

Understanding Social and Environmental Hazards in Urban Areas: An Analysis from Barranquilla, Colombia

The present research aims to understand the challenges faced by a Colombian city in the context of multidimensional risk scenarios, given the existing demographic and socio-economic conditions and local perspectives and perceptions regarding socio-environmental risks. The research was undertaken in the city of Barranquilla, northern Colombia. A survey was designed to analyze (1) the general socio-economic and vulnerability conditions of a communities’ sample, (2) information related to hazards and disaster risk in their neighbourhoods, and (3) information on actions to mitigate risk. Three hundred and ninety-one people were surveyed. Likert scale and Pearson's Chi-square test and descriptive, inferential statistical methods, regression models, and the Mann–Whitney U test were used to process the results. Respondents lived, in general, under precarious socio-economic conditions (such as low income or lack of infrastructure and others). Given socio-environmental constraints, the research revealed that hazards such as urban stream flooding and robbery were the most negatively associated with the respondent’s quality of life. Regarding the actions to avoid losses, 84% of respondents had not implemented any preventive action. Respondents also have low awareness of the need to implement risk prevention actions. Social risks and the configuration of anthropic hazards stand out as principal centres for concern.

Method for Operating Drainage Pump Stations Considering Downstream Water Level and Reduction in Urban River Flooding

Korea experiences increasing annual torrential rains owing to climate change and river flooding. The government is expanding a new drainage pump station to minimize flood damage, but the river level has not been adjusted because of torrential rains. Therefore, the river level must be adjusted to operate the drainage pump station, and it can be adjusted through the reservoir of the drainage pump station. In this study, we developed a method for operating drainage pump stations to control the river level and verify the effectiveness of the proposed method. A stormwater management model (SWMM) was used to simulate the Suyeong River and Oncheon River in Busan, Korea. The rainfall data from 2011 to 2021 were investigated. The data were sorted into ten big floods that occurred in Busan. The model was calibrated with actual rainfall data. The water level of the Suyeong River and the Oncheon River was the highest in most simulations. The simulation results showed an average decrease of 3018.2 m3 in Suyeong River flooding, and the Oncheon River needed to be supplemented due to structural problems. As a result of the recombination by simply supplementing the structural problems of the Oncheon River, the average flooding of 194.5 m3 was reduced. The proposed method is economical and efficient for reducing urban stream flooding in areas susceptible to severe damage caused by climate change.

Recent advances in environmental DNA‐based biodiversity assessment and conservation

Recent advances in environmental DNA‐based biodiversity assessment and conservation

Water quality integrated system: A strategic approach to improve bathing water management

In the Adriatic Sea, massive rainfall events are causing flooding of rivers and streams, with severe consequences on the environment. The consequent bacterial contamination of bathing water poses public health risks besides damaging tourism and the economy. This study was conducted in the framework of WATERCARE, an EU Interreg Italy-Croatia Project, which aims at reducing the impact of microbial contamination on Adriatic bathing water due to heavy rainfall events drained in the local sewage network and; enhancing the quality of local waters; and providing support for the decision-making processes regarding the management of bathing water in line with EU regulations. The study involved the development of an innovative water quality integrated system that helps meet these objectives. It consists of four components: a real time hydro-meteorological monitoring system; an autosampler to collect freshwater samples during and after significant rainfall events; a forecast system to simulate the dispersion of pollutants in seawater; and a real-time alert system that can predict the potential ecological risk from the microbial contamination of seawater. The system was developed and tested at a pilot site (Fano, Italy). These preliminary results will be used to develop guidelines for urban wastewater and coastal system quality assessments to contribute to develop policy actions and final governance decisions.

Sedimentology and Miocene-Pliocene depositional evolution of the stream-dominated alluvial fan deposits at circum-Sultandağları region

Yalvaç and Ilgın basins surrounding the Sultandağları opened due to orogenic collapse in the early Miocene. The NW-SE trending Çakırçal and Akşehir Faults, forming boundaries with these basins, caused both opening of the basins and uplifting of the Sultandağları. During the Miocene-Pliocene period, alluvial fans fed from the Sultandağları developed on the basin margins, while lacustrine carbonate and clastic depositions occurred in the basin's interior. Alluvial fan sediments are laterally and vertically transitional with lacustrine sediments and alternate several times in the sequence. Alluvial fans, widespread in the region, consisting of "debris flow", "high density stream flood", "braided river" and "meandering river" deposits. Fan deposits that pass from the high-energy fluvial facies at the basin margin to the low-energy fluvial facies towards the basin interior have been interpreted as "stream-dominated alluvial fan deposits". Age data obtained from the fan deposits of the Yalvaç and the Ilgın basins show that the Sultandağları concurrently feeds the alluvial fans on both flanks. Alluvial fan deposition around the Sultandağları occurred under the control of tectonic and climatic processes. Tectonism led to the formation of basins and the creation of source areas. Simultaneously, the climate maintained the streams to be perennial by precipitation, thus proving a continuous sediment supply to the basins. Tectonism and climate-controlled base-level changes determined the quantity of sediments carried to the basin from the source area, causing regressive or transgressive developments.

Impact Assessment of Flood Damage in Urban Areas Using RCP 8.5 Climate Change Scenarios and Building Inventory

Korea has frequent flood damage due to localized torrential rain and typhoons as a result of climate change, which causes many casualties and property damage. In particular, much damage occurs due to urban inundation caused by stream flooding as a result of climate change. Thus, this study aims to analyze the effect of climate change on flood damage targeting the Wonjucheon basin, which is an urban stream flowing the city. For future rainfall data, RCP (Representative Concentration Pathways) 8.5 climate change scenario data was used, statistical detailed using SDQDM (Spatial Disaggregation with Quantile Delta Mapping) techniques, and daily data was downscaled using Copula model. In general, the flood damage rate is calculated by using the area ratio according to the land use in the administrative district, but in this study, the flood damage rate is calculated using the flood damage rate proposed in the multi-dimensional flood damage analysis using Building Inventory. Using the created future rainfall data and current data, the runoff in the Wonjucheon basin, Wonju-si, South Korea, by rainfall frequency was calculated through the Spatial Runoff Assessment Tool (S-RAT) model, which was a distributed rainfall-runoff model. The runoff was calculated using 100-year and 200-year frequency rainfalls for a four-hour duration and the flood damage area was calculated by applying the calculated runoff to the Flo-2D model, was developed by Federal Emergency Management Agency (FEMA) in United State of America, which was a flood inundation model. As a result of calculating the amount of discharge, it was analyzed that the average amount of discharge increased by 16% over the 100-year, 200-year frequency. The calculated result of the flood damage area was analyzed and the analysis results showed that the future flood damage area increased by around 30% at the 100-year frequency and around 15% at the 200-year frequency. The estimated flood damage by rainfall frequency was calculated using the flood damage area by frequency and multi-dimensional analysis, and the analysis result exhibited that the damage increased by around 23% at the 100-year frequency and around 45% at the 200-year frequency.

Estimation of Flood Resilience Index Using Hydrological and Hydraulic Models in Rural Area

Since countermeasures of floods in Korea are focused only on facility restoration, recovery from flood damage cannot be repaired quickly. Then, it is necessary to reduce vulnerability to flooding and restore the state before the flood. Since there is no application of flood resilience to rural areas, it is necessary to introduce the FRI (Flood Resilience Index) and to apply flood resilience assessment to systematically and efficiently recover and manage flood damage in rural areas as well as in cities. In this study, the discharge was calculated by HEC-HMS (Hydrologic Engineering Center-Hydrologic Modeling System) and the hydraulic analysis was conducted by HEC-RAS (Hydrologic Engineering Center-River Analysis System) and MIKE 21 for Dal Stream flood damage upstream of Goesan Dam in 2017. A flood map was made using three models and GIS (Graphic Information System), and then the FRI of Dal Stream was calculated. The calculated FRI values suggest methods that can be applied to the resilience to flood damage in rural areas as well as cities.

Floods of glacial streams in Qaanaaq, northwestern Greenland

Floods of glacial streams in Qaanaaq, northwestern Greenland