Hasil untuk "River protective works. Regulation. Flood control"

Carlos H. Aparicio Uribe, Beniamino Russo, Jackson Téllez‐Álvarez et al.

ABSTRACT Given the increasing flooding incidents in metro stations globally, underground space infrastructures must guarantee users' safety. This manuscript characterises the hydraulic behaviour of a flood‐prone access stairs of the Paral·lel Metro station in Barcelona. Using a real‐scale stairs model at the Technical University of Catalonia (UPC) and the Computational Fluid Dynamics (CFD) software FLOW‐3D. Hydraulic parameters; water velocity, and depth were analysed under different discharges. Human instability criteria, Momentum of Flow (MF) and Specific Force Per Unit Width ‘SFPUW’ (M0) indicated that the most hazardous zone was the lower part of the stairs. Sectorised analyses showed that specific locations like the walls and proximities to risers presented lower safety criteria values compared to the centre of the stairs and steps' borders. Also, the numerical model closely mirrored the aerated flow experimentally observed. These findings provide useful information for future research campaigns aiming to improve urban resilience to face underground evacuation of flooded stairs.

Zeng Bowei, Huang Guoru, Yang Ge

ABSTRACT Urban flood disasters demand dynamic assessment of population risk, yet most evacuation models fail to capture the multifaceted, time‐varying nature of such events. To address this gap, this study develops the modular urban flood‐evacuation (MUFE) framework, an integrated approach to dynamic urban flood risk assessment. MUFE explicitly models pedestrian and vehicle behaviors under inundation and their interactions with evolving hydrodynamic conditions. The framework is tailored for island cities facing compounded threats from storm surges and sea‐level rise, and is demonstrated on Haidian Island, Haikou, China. The research couples multi‐scenario rainfall‐tide hydrodynamic simulations (via InfoWorks ICM) with an agent‐based model implemented in the open‐source Mesa framework. Mesa enables the explicit representation of pedestrian and vehicle agents operating under perceive‐decide‐act cycles and local information constraints. This integration enables joint analysis of hydrodynamic hazard fields—shaped by dynamic tidal fluctuations—and the behavioral responses of pedestrians and vehicles. The framework is modular, allowing alternative hydrodynamic or data‐driven flood models to be coupled for transparent comparison. Simulation results show that pedestrian hazard exposure varies markedly across space and time, shaped by adaptive evacuation behavior, shelter availability, and tide dynamics. Small vehicles are more susceptible to instability—even under shallow depths—while larger vehicles are more resilient but not immune under severe conditions. These patterns underscore the need for differentiated evacuation planning and targeted infrastructure resilience measures in island cities.

Masoumeh Lari, Aliakbar Nazari Samani, Aqil Tariq et al.

Owing to the overuse of wild land, the mountainous watersheds in Iran have experienced severe land degradation and consequent downstream flooding. To design effective soil and water conservation strategies, it is crucial to understand how sediment yield and flow fluctuations respond to conservation practices. The purpose of this study was to evaluate the GeoWEPP model for runoff and sediment yield predictions via multiple endemic inputs, namely, climate, soil characteristics, topography, and LULC. Through the calculation of four parameters related to soil properties, namely, the effective hydraulic conductivity (ke), baseline critical shear stress (τc), baseline rill erodibility (kr), and baseline interrill erodibility (ki), the assessment of the initial run illustrates that calibration is inevitable. Given the geographical context and summer snowmelt dynamics, the model was unable to estimate summer runoff accurately. To address this problem, additional modeling for meltwater runoff was incorporated. The NSE and R2 values for discharge are 0.74 and 0.84, respectively, while those for sediment yield are 0.64 and 0.51, respectively. The results indicated that good predictions of runoff and sediment yield were obtained with the calibrated GeoWEPP model at the watershed scale. The key contribution of this research is the assessment of how eight biological conservation scenarios influence watershed behavior. Eight biological conservation scenarios were considered, representing incremental increases in canopy cover in poor, medium, and good pastures, both individually and in combination, as well as an additional scenario including expanded channel cover. The results showed that enhancing canopy cover could lower runoff and sediment yield by up to 44 % and 47 %, respectively, while the channel-cover scenario could lead to increases of up to 54 % and 67 %, respectively. These findings demonstrate the model's effectiveness in accurately replicating the hydrological and erosional responses resulting from soil and water conservation strategies.

Xinmiao Cao, Teng Lin, Jiahui Li et al.

AbstractExploring optimal operational schemes for synergistic development is crucial for sustainable management in river basins. This study introduces a multi‐objective synergistic optimization framework aimed at analyzing the interplay among flood control, ecological integrity, and desilting objectives under varying water‐sediment conditions. The framework encompasses multi‐objective reservoir optimal operation, scheme decision, and trade‐off analysis among competing objectives. To address the optimization model, an elite mutation‐based multi‐objective particle swarm optimization (MOPSO) algorithm that integrates genetic algorithms (GA) is developed. The coupling coordination degree is employed for optimal scheme decision‐making, allowing for the adjustment of weight ratios to investigate the trade‐offs between objectives. This research focuses on the Sanmenxia and Xiaolangdi cascade reservoirs in the Yellow River, utilizing three representative hydrological years: 1967, 1969, and 2002. The findings reveal that: (1) the proposed model effectively generates Pareto fronts for multi‐objective operations, facilitating the recommendation of optimal schemes based on coupling coordination degrees; (2) as water‐sediment conditions shift from flooding to drought, competition intensifies between the flood control and desilting objectives. While flood control and ecological objectives compete during flood and dry years, they demonstrate synergies in normal years (r = 0.22); conversely, ecological and desilting objectives are consistently competitive across all three typical years, with the strongest competition observed in the normal year (r = −0.95); (3) the advantages conferred to ecological objectives increase as water‐sediment conditions shift from flooding to drought. However, the promotion of the desilting objective requires more complex trade‐offs. This study provides a model and methodological approach for the multi‐objective optimization of flood control, sediment management, and ecological considerations in reservoir clusters. Moreover, the methodologies presented herein can be extended to other water resource systems for multi‐objective optimization and decision‐making.

Xinghua He, Zihan Zhao, Yanqin Zhang et al.

The Yangtze River Delta, renowned for its intricate waterway system and fertile soil, is a crucial ecological zone in China. However, anthropogenic activities have led to significant changes in sediment nitrogen (N) forms and associated ecological risks in this region. This study aims to comprehensively investigate the occurrence of various N forms in the sediment of the Yangtze River Delta plain-river network through field sampling and laboratory analysis and to assess their ecological implications. The results revealed that the concentration of total N in river water (TNw) ranged from 1.24 to 5.96 mg/L, decreasing from northwest to southeast. The nitrate in river water (NO3−–Nw) was the major species of TNw, accounting for 67.97% of the total. The average values of TN, total carbon (TC), and total sulfur (TS) in the sediment were 1.97, 18.36, and 1.35 mg/g, respectively. The predominant N fractions in the sediment were residual nitrogen (RN) (72.42%) and hydrolyzable nitrogen (HN) (22.44%). The ammonia in river water (NH4+–Nw) was significantly affected by the sediment N (p < 0.05). Residential density (RD) and industrial density (ID) were significantly positively correlated with the concentration of TNw (p < 0.01), and ID was significantly positively correlated with increased RN (p < 0.05), which suggests that industrial wastewater may be a source of RN. The risk assessment revealed that 36% of the sediment samples were above the moderate TN pollution level. Furthermore, 94% of the sediment was contaminated with organic matter, with 66.7% specifically affected by organic N contamination. High riverine RN and NO3−–Nw contents indicate serious ecological pollution risks in the complex river network area in the Yangtze River Delta. This study provides valuable insight into N cycling and associated ecological risks in the Yangtze River Delta plain-river network, which is crucial for developing effective management strategies to safeguard the ecological health of this vital region.

Mahshid Khazaeiathar, Britta Schmalz

ABSTRACT Discharge modeling utilizing novel deep learning techniques is highly recommended due to their high efficacy in modeling nonlinear time series. In this study, a hybrid discharge model is developed, termed wavelet‐based long short‐term memory (WLSTM), by integrating wavelet transform and Long Short‐Term Memory (LSTM). This technique focuses on improving discharge prediction by effectively denoising the input data and amplifying the most relevant temporal patterns for the model. However, since LSTM models depend on underlying data patterns, their performance can be significantly affected by the intensity of nonlinearity in hydrological time series. To address this, we introduce a novel method using ApEn (Approximate Entropy) to quantify nonlinearity intensity. Then, we applied Fuzzy Clustering to classify nonlinearity into weak, moderate, and high nonlinearity categories. The performance of both LSTM and WLSTM is evaluated using daily discharge data from 16 hydrometric stations in Hesse, Germany, for the period 2000–2017. The results notably show a remarkable reduction of 66.43% for Root Mean Squared Error (RMSE) and of 45.49% for Mean Absolute Percentage Error (MAPE) for WLSTM performance compared to LSTM. Furthermore, WLSTM increased R‐squared (R2) by 2.06%. This research acknowledges that there is a direct correlation between the streamflow nonlinearity and WLSTM accuracy. With increasing nonlinearity intensity, WLSTM captures the complexity of streamflow patterns more effectively. RMSE is 0.1194, 0.0836, 0.0547 and R2 is 0.9976, 0.9990, 0.9994 for weak, moderate, and high nonlinearity groups, respectively. This study highlights the importance of streamflow nonlinearity analysis in improving flood forecasting and risk management.

Houda Lamane, Latifa Mouhir, Rachid Moussadek et al.

Machine learning (ML) has become a powerful tool for predicting suspended sediment concentration (SSC). Nonetheless, the ability to interpret the physical process is considered the main issue in applying most of ML approaches. In this regard, the current study presents a novel framework involving four standalone ML models (extra trees (ET), random forest (RF), categorical boosting (CatBoost), and extreme gradient boosting (XGBoost)) and their combination with genetic programming (GP). Three metrics (coefficient of correlation (r), root mean square error (RMSE), and Nash–Sutcliffe model-fit efficiency (NSE)) and a more advanced interpretation system SHapley Additive exPlanations (SHAP) are used to assess the performance of these models applied to hydro-climatic datasets for prediction of SSC. The calibration process was based on data from 2016 to 2020, and the validation was done for 2021 data. Further description and application of the framework are provided based on a case study of the Bouregreg watershed. The results revealed that all implemented models are efficient in SSC prediction with NSE, RMSE, and r varying from 0.53 to 0.86, 1.20–2.55 g/L, and 0.83–0.91 g/L respectively. Box plot diagrams confirm the enhanced performance of these combined models, and the best-performing ones for the four hydrological stations being the combined RF + GP model at the Aguibat Ziar station, the combined XGBoost + GP model at the Ain Loudah station, the CatBoost model at the Ras Fathia station, and the RF model at the Sidi Med Cherif station. The interpretability results showed that flow (Q) and seasonality (S) are the features most impacting SSC. These outcomes indicate that the applied models can extract accurate and detailed information from the interactions between the hydroclimatic factors and the generation of sediment by erosion (output). ML approaches illustrated the good reliability and transparency of the models developed for predicting SSC in a semi-arid setting, offered new perspectives for reducing ML models' “black box” character, and provided a useful source of information for assessing the consequences of SSC on water quality. The SHAP system and exploring other interpretable techniques are recommended to provide further information in future research. In addition, incorporating additional input data could enhance SSC predictions and deepen understanding of sediment transport dynamics.

Alessio Cislaghi, Emanuele Morlotti, Sara Cucchiaro et al.

Abstract Torrent control structures are essential countermeasures against potential losses from flood to debris flow events. The durability of these structures hinges upon several factors, including the structure's design, construction materials and ongoing maintenance as well as the physical pressures they are under. Over the past half‐century, a decline in investments allocated to routine maintenance activities, coupled with the natural degradation of these structures, has contributed to a reduction in their protective capacity. In this context, monitoring and maintaining existing structures are essential actions. This study presents a comprehensive proposal for a routine inspection process adopted for torrent control structures along four rivers in North Italy. The results of the first‐level inspections consist of a dataset encompassing missing details (e.g., width, length, height, construction age, materials used), present condition of structures and functionality. The further step is to predict the vulnerability of the inspected torrent control structures; so, the Markov chain model is implemented for forecasting their service life, also in function of different maintenance strategies. Furthermore, this study serves as a valuable resource for reinforcing the role of the first‐level inspections and ongoing monitoring, which is essential for planning future investments in watershed management, especially in the routine maintenance of torrent control structures.

Frank denHeijer, Pieter H. A. J. M. vanGelder, Matthijs Kok

ABSTRACT Objective of this paper is to study how reliability standards, expressed as probabilities of dike segment failure, can be practically updated to improve opportunities for risk‐based dike design and planning. The approach to assess the economic optimal flood probability, used by the Dutch Delta Committee (1958, in this paper referred to as Van Dantzig), is adapted to reflect time‐dependent effects of a.o. climate change and subsidence. Furthermore, the approach is adapted to reflect overtopping instead of overflow and it is extended to include reinforcements over time. A comparison of the results of the Adapted Van Dantzig approach with the economic optimal probabilities used as input for the recently formalised Dutch standards (2017) is performed for 73 dike segments in the Netherlands, showing good agreement. Following the Adapted Van Dantzig approach, an analytical relation is developed for economic optimal design horizons, dependent on the dike design, and characteristics of load, investment, climate effect, and economic growth. Finally, a dynamic and simple‐to‐use approach is developed to enable updating of the economic optimal reliability based on a proposed design and investment planning. This can serve to consider whether an existing reliability standard still fits adequately or needs updating.

Chiara Arrighi, Fabio Castelli

ABSTRACT Art cities are characterized by peculiar exposure and vulnerability aspects which are rarely addressed in flood risk studies. This works investigates art cities in terms of exposure and resilience by considering the effects of cultural heritage. Flood hazard considers a “what‐if” scenario comparison based on an historical event as it occurred in the past and as it would occur today and in future with countermeasures in place. The analysis is carried out in the city of Florence (Italy), a UNESCO World heritage site, affected by the last flood in 1966. The results show that countermeasures have slightly reduced inundation extent (−7%) and depths. Exposure of buildings has increased (+17%), but the exposed residential population has decreased (−38%) due to gentrification. On the other side, the fluctuating population exposure has dramatically increased (+1511%). Finally, despite the limited flood hazard reduction, resilience has increased, with a reduction of post‐event recovery time (−21%). In future, completed mitigations works will reduce substantially flood hazard and exposure of residents and tourists. It appears that cultural heritage plays a twofold and contrasting role. On the one hand, it attracts a fluctuating population, which increases exposure, and, on the other, it fosters the recovery.

Daniel Kwabena Twerefou, Jacob Opantu Abeney, Reuben Tete Larbi et al.

Abstract The intent of households to relocate amidst floods in Ghana's Greater Accra Metropolitan Area, using combined socio‐demographic and physical factors is analyzed within 1206 households. The National Master Sampling Frame of Ghana's Population and Housing Census is utilized for the sampling. The Probit estimation technique is employed to understand the intersectionality of social, economic, demographic, and physical considerations influencing households' decision‐making regarding relocation amidst flood risks. The findings show households' reluctance to relocate contrary to relocation considered mostly as preferred adaptation. The likelihood of relocating exhibited a non‐linear pattern, decreasing only when a population was younger until age 55 before reversing. Indigenous households preferred not to relocate. In communities where place attachment and revenue sources significantly impacted relocation decisions, households with secondary education, past flood experiences, and non‐indigenous status influenced higher perception of flood risk. Therefore, relocation as an effective global adaptation strategy to floods is not widespread. Thus, empowering households to accept a certain level of flood risk potentially avoids maladaptation and involves a combination of hard infrastructure measures and regulatory approaches in places of residence that do not compromise livelihoods. However, if relocation becomes necessary, a right‐based approach must be favored over an absolute risk‐based approach.

Alexander A. Voronin, Anna A. Vasilchenko

Setiadi Setiadi, Asep Sumaryana, Herijanto Bekti et al.

Abstract Floods have turned into an annual disaster in Indonesia, many metropolitan areas are affected by flood and require policies to deal with this phenomenon. This study was aimed to analyze the policy on flood control in Bandung City, West Java, Indonesia. Bandung City was chosen as a case study because it has the “Local Government Work Plan” (RKPD) document for flood control since 2020. Using a qualitative approach, this study involved informants from the governments, community, and academics to determine the implementation of the regulation. Data validation focused on triangulation of sources from interviews, literature reviews, and field observations. This research showed that the flood control policy is related to the planning documents, but there are several challenges that have hindered the accomplishment such as land conversion, poor waste, and drainage management, as well as critical watershed and illegal building. Potential strategies for strengthening flood control policy include the development of retention ponds, normalization and naturalization of rivers, watershed landscape management, strengthening disaster mitigation, as well as reinforcing bureaucracy and policy. Flood control in Bandung City requires a mutual awareness that disasters can be controlled by policies and the active participation of all parties.

محمود حبیب نژاد روشن, کاکا شاهدی, سیدحسین روشان

مقدمه سیل، به‌عنوان یکی از مخرب‌ترین بلایای طبیعی است که باعث تلفات جانی، خسارت‌های زیرساختی و اقتصادی قابل توجه و نابسامانی‌های اجتماعی، در سراسر جهان می‌شود. با توجه به این‌که سیل پدیده‌ای پویا و چند بعدی است، داده‌های سامانه اطلاعات جغرافیایی (GIS) و سنجش از دور (RS) تا حدود زیادی برای کشف وسعت مناطق سیل‌زده کاربرد دارد و در تهیه نقشه حساسیت‌پذیری و خطر سیل نقش ویژه‌ای دارند. نقشه حساسیت به سیل، برای توصیف مناطق در خطر سیل و برنامه‌ریزی برای ایجاد طرح‌های کنترل سیل، ضروری است.   مواد و روش‌ها در این پژوهش، شناسایی مناطق سیل‌گیر در حوضه کارون بر اساس فرایند تحلیل سلسله مراتبی (AHP) در محیط سامانه اطلاعات جغرافیایی و صحت‌سنجی آن با شاخص آبی NDWI، استخراج شده از تصاویر ماهواره لندست 8، مد نظر بوده است. به این منظور، ابتدا 15 پارامتر موثر در وقوع سیلاب از جمله مقدار و جهت شیب، طبقات ارتفاعی، انحنای زمین، بارندگی، فاصله از آبراهه، تراکم آبراهه، فاصله از گسل، تراکم گسل، فاصله از جاده، تراکم جاده، لیتولوژی، شماره منحنی (CN)، کاربری اراضی، شاخص رطوبت توپوگرافی (TWI) و شاخص قدرت جریان (SPI)، انتخاب شدند. وزن‌دهی این پارامترها، بر اساس روش فرایند AHP در محیط نرم‌افزار Expert Choice انجام شد. در نهایت، با استفاده از دستور تلفیق لایه‌ها، بر اساس وزن‌دهی روش AHP در GIS، نقشه نهایی پهنه‌بندی خطر سیلاب به‌دست آمد. برای صحت‌سنجی نقشه خطر سیلاب به‌دست آمده، از شاخص آبی NDWI بهره گرفته شد.   نتایج و بحث نتایج مدل AHP نشان داد که موثر‌ترین عوامل در بروز خطر سیلاب در حوضه کارون به‌ترتیب بارندگی، مقدار شیب و طبقات ارتفاعی هستند که برای کاهش خسارات سیلاب و ارائه راهکارهای مدیریتی، این عوامل بایستی مورد توجه قرار گیرند. همچنین، نتایج بیانگر آن است که مناطق پایین‌دست حوضه دارای بیشترین خطر سیل‌گیری را دارند و بیش از نیمی از سطح حوضه (52.24 درصد)، دارای پتانسیل سیل‌خیزی متوسط است.   نتیجه‌گیری تهیه نقشه مناطق مستعد سیل، یکی از سازنده‌ترین روش‌هایی است که امکان کاهش خسارت‌های خطر سیل را فراهم می‌کند و به برنامه‌ریزان، ذی‌نفعان و تصمیم‌گیران کمک می‌کند تا نظارت مناسبی بر مناطق سیل‌خیز داشته باشند و توسعه اقتصادی-اجتماعی مناسب و پایدار را تضمین کنند.

برومند صلاحی, مهناز صابر, عباس مفیدی

در این پژوهش، دورنمای تبخیر-تعرق مرجع (ETo) بخش جنوبی حوزه آبخیز رودخانه ارس تحت شرایط تغییر اقلیم با استفاده از ریزگردان SDSM ترسیم شد. برای این منظور، از داده‌­های هواشناسی ایستگاه­‌های سینوپتیک منتخب واقع در این حوضه استفاده شد. پس از دریافت خروجی ریزگردانی­ شده برای پارامترهای مورد نیاز برای برآورد ETo به روش پنمن-مانتیث فائو شماره 56 برای آینده نزدیک (2021 تا 2050 میلادی) اقدام به محاسبه آن شد. در این راستا، از داده­‌های روزانه بازتحلیل NCEP و داده­‌های ایستگاهی کمینه و بیشینه دما، سرعت باد، رطوبت نسبی و ساعات آفتابی در مقیاس روزانه و نیز داده‌­های خروجی مدل CanESM2 تحت سناریوهای RCPs برای تولید داده‌­های ایستگاهی آینده برای تخمین ETo حوضه ارس استفاده شد. ایستگاه­‌های مورد مطالعه شامل اهر، اردبیل، پارس­آباد، جلفا، خوی و ماکو بود و دوره پایه برای داده­‌های مورد نظر 2005-1985 در نظر گرفته شد. ابتدا، کارایی SDSM در شبیه­‌سازی پارامترهای مورد نیاز برای تخمین ETo از طریق مقایسه داده‌­های شبیه‌سازی شده NCEP با داده­‌های ایستگاهی ارزیابی شد. مقایسه آن‌ها نشان‌دهنده کارایی مناسب مدل در شبیه­‌سازی داده‌­ها بود. لذا، پارامترهای اقلیمی با استفاده از مدل CanESM2 تحت سناریوهای RCP برای آینده شبیه­‌سازی شده، پس از محاسبه مقادیر ماهانه آن‌ها، برای تخمین ETo حوضه به CROPWAT وارد شده و مقدار و روند متغیر برای سه دهه آتی محاسبه شد. نتایج نشان داد، ETo حوضه در دوره آتی نسبت به دوره پایه به‌طور متوسط حدود هفت میلی‌متر در سال افزایش خواهد یافت. برحسب ایستگاهی نیز ETo در پارس‌­آباد (102 میلی‌متر) و جلفا (66 میلی‌متر) افزایشی خواهد بود که این افزایش به معنی افزایش نیاز آبی گیاهان در آینده نیز است. همچنین، روند آتی ETo در خوی، ماکو، اهر و اردبیل کاهشی خواهد بود.

Jun Xia, Jin Chen

Roger E. Auster, Stewart W. Barr, Richard E. Brazier

Abstract Natural flood management (NFM) methods work with natural processes to reduce flood risk, while often providing additional benefits such as water quality improvement or habitat provision. Increasingly, the activity of an animal—beavers—is recognised to potentially provide flow attenuation, along with multiple benefits for the environment and society, but there can also be associated challenges. We use Q‐Methodology to elicit and understand human perspectives of beavers and their potential role in flood management among communities living downstream of beavers at three sites in England (Cornwall, Yorkshire and the Forest of Dean). This is the first time a study has focused on downstream communities as the primary stakeholders. We identify diverse perspectives that exhibit a range of value judgements. We suggest a catchment‐based approach to beaver management and public engagement may facilitate deeper recognition of contextual perspectives in decision‐making and enable knowledge dissemination with communities. Further, we examine the relationship between beavers and other NFM methods through these perspectives. In doing so we identify features that relate to the unique element of relying on the natural behaviour of beavers for flood management, rather than human flood managers being the primary decision‐makers.

Kazuki Yamanoi, Satoru Oishi, Kenji Kawaike et al.

Abstract Predictive simulation of concurrent debris flows using only pre‐disaster information has been difficult, partly because of problems faced in predicting debris‐flow initiation locations (i.e., slope failure). However, because catchment topography has convergent characteristics with all channels in it joining each other as they flow downstream, damage to downstream areas could be predicted using relatively inaccurate initiation points. Based on this hypothesis, this study uses debris‐flow initiation points generated randomly with statistical slope failure prediction and performs a many‐case simulation across numerous initiation points to quantify the effect of slope‐failure locations in terms of deviations in the predicted water level and topographic change. This paper presents the results of 2D simulations based on a conventional debris‐flow model that was run on a supercomputer to realise simulations of many cases. The obtained relative standard deviation was found to decrease as the debris flow and sediment‐laden flood approached the downstream area, indicating that the predictability of the inundation and topographic change can be decided from the terrain characteristics.

Jaewon Kwak

An assessment of dam operation is essential in dam management; however, there is a lack of a simple method that could be used in actual practice. This study aims for an actual dam operation evaluation method for flood and low-flow control of the three multi-purpose dams of Soyanggang, Chungju, and Hoengseong in the Han River basin, South Korea. Frequency matching method was applied to make a pair of cumulative distribution function (CDF) using daily dam inflow and outflow records. Runoff increasing and flood reduction rates are derived using CDFs of total and annual records. As a result, the average flood mitigation rates of the Chungju dam is approximately 35% annually and is relatively disadvantaged than the Soyanggang dam, which is 67.7% annually, due to small flood control capacity. The Hoengseong dam appeared to have a small flood reduction rate, but its runoff increasing rate is 94.7% annually because of the 209 km2 upper basin area. The suggested method in this study could be used as a simple and intuitive field method to evaluate dam operations. Also, according to the annual evaluation, the Soyanggang and Chunju dam need more aggressive and anticipative operations for flood control such as pre-discharge before flooding or modify the Restricted Water Level (RWL) for flood seasons. On the other hand, Hoengseong dam need further data and studies.