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

M. Meybeck

C. J. Gabbe, Ryan Anderson, Veronica Miranda

ABSTRACT Housing in the United States faces an escalating threat of flooding due to climate change and population growth patterns. This study focuses on the most flood‐prone neighborhoods of Santa Cruz, California, to examine development trends and explain the drivers of residential growth in these areas. We take a mixed‐methods approach that combines an analysis of development trends, a content analysis of 11 adopted plans, and four semi‐structured interviews. We find that housing growth in the special flood hazard area (SFHA) has increased since 1960 and that the majority of new development in the study area is in the SFHA. Local plans generally acknowledge flood hazards—though they lack data about disparities in risk—and are particularly focused on resisting and accommodating water. Interviewees asserted that risks from flooding have been largely mitigated via infrastructure and policy; housing needs outweigh flood risks as a primary concern for residents; and building in the downtown SFHA is the most environmentally sustainable development alternative. Policy implications for local governments include the need to plan for equity and incorporate future flood risks; the importance of plan consistency; and the opportunity to promote a balanced set of strategies.

Murel Truu, Ivar Annus, Nils Kändler

ABSTRACT Urban areas are increasingly vulnerable to pluvial floods, a threat that is exacerbated by climate change and urbanisation. Current risk assessment methods often lack scalability and practical applicability across diverse urban contexts and varying capacities. This study introduces a novel comprehensive framework for multi‐level pluvial flood risk assessment, which provides a systematic approach to evaluating hazard, exposure, and vulnerability across citywide, catchment, and sub‐catchment levels. By integrating geographic information systems with adaptive modelling techniques, the framework enables resource‐efficient prioritisation and dynamic risk management tailored to urban development and climate change scenarios. Case studies based on Estonian cities illustrate how this approach can guide effective flood risk mitigation at various spatial scales.

Yeongeun Ji, Yunji Lim, Donggyun Kim et al.

ABSTRACT With climate change, the accurate prediction of river water levels has become increasingly critical, particularly in confluence areas where multiple tributaries merge, resulting in complex hydrodynamic interactions. This study evaluates direct prediction (DP) and recursive prediction (RP) using a virtual sensor approach, with a focus on the role of forecasted rainfall. An LSTM model was trained using upstream rainfall and water level data to predict downstream levels, and its performance was assessed across various lead times (LT) using MAE, RMSE, NSE, and QER. For a short event (Event #8), DP without forecasted rainfall achieved an NSE of 0.42 at LT = 12 h, while RP dropped to −11.69. With forecasted rainfall, RP improved, maintaining an NSE of 0.75 compared to DP's 0.51. For a long multi‐peak event (Event #9), RP with forecasted rainfall achieved NSE values of 0.98 at 1 h and 0.91 at 12 h, outperforming DP (0.97 at 1 h, 0.42 at 12 h). These results demonstrate that DP is more reliable when forecasted rainfall is unavailable, whereas RP becomes superior when such data are available. Overall, the study highlights the potential of virtual sensors to enhance flood forecasting and disaster preparedness in confluence zones lacking direct monitoring stations.

Rafael Silva Araújo, Miho Ohara, Mamoru Miyamoto et al.

ABSTRACT People's vulnerability to disasters depends largely on their social and physical aspects, such as economic disadvantages and mobility constraints related to age. Those characteristics will influence how individuals experience the disaster and recover. Thus, assessing the vulnerable population's location and exposure to hazards such as floods is important for designing disaster risk reduction policies. This study conducts such an analysis considering five disadvantage dimensions: age, gender, race, socioeconomic status, and housing spatially distributed in cell grids, which were compiled into a disadvantage index (DI). The DI is further overlayed with the population density (DI*pop.dens.). From the derived DI*pop.dens. map, priority areas for flood management budget allocation can be extracted. The methodology is applied to the Itapocu River Basin (IRB), in southern Brazil, as a case study and compared with the flood inundation area estimated by a hydrological simulation. The places that could be regarded as priority areas for future public policy were classified into high, medium, and low‐priority areas, considering higher exposure of the disadvantaged population, higher flood depth, and higher flood frequency. In the IRB, there are priority areas near the main urban areas. Thus, flood control budgets are suggested to be allocated there to protect the vulnerable population.

Selemon Thomas Fakana, Fekadu Fanjana Falta, Debebe Dana Feleha

ABSTRACT Flooding is among the most devastating natural catastrophes affecting human life and property. Climate change and environmental degradation have exacerbated flooding disasters. Developing countries experience greater damage from flooding due to their low resilience, limited financial resources, weak early warning systems, and technological limitations. Accurate data, prediction, delineation of vulnerable areas, and formulation of local action plans can help minimize the extent of economic losses and fatalities due to flooding. In the current study area, limited data are available to lessen flood potential risks. Remote sensing and GIS approaches were adopted for mapping potential flood‐susceptible areas. Topographical, hydrological, and spectral indices conditioning factors were integrated, and a weighted overlay analysis was performed in ArcGIS. The results revealed that about 8.73%, 77.16%, and 14.08% of the study region are categorized as susceptible, moderately susceptible, and less susceptible to flooding, respectively. The findings would help government authorities and relevant bodies in developing early warning systems, advancing technology, creating local action plans, and formulating flood hazard mitigation and adaptation strategies.

Tabea Klör, Philip Bubeck, Rainer Bell et al.

ABSTRACT The number of individuals exposed to flooding is increasing and is projected to increase in the future. Catastrophic events like the July 2021 flood in Germany's Ahr Valley (Rhineland‐Palatinate) illustrate the severe and often long‐lasting mental health impacts such disasters can cause. However, research on the psychological consequences of extreme flooding remains less developed than studies on physical damage. Gaining a clearer understanding of individual mental burden following such events is essential for tailoring recovery efforts to address mental health needs effectively. This study investigates how various factors—including flood characteristics, circumstances of the recovery process, personal characteristics, perceptions, and sociodemographic characteristics—affect self‐reported mental burden. Using binary logistic regression, we analyzed responses from 277 individuals affected by the July 2021 flood in the Ahrweiler district. Results show that even 18 months after the event, 42.6% of respondents continued to experience high to very high levels of mental burden. Interestingly, the analysis found that sociodemographic variables—particularly, health status—and personal characteristics and perceptions (e.g., persistent mental preoccupation) had a greater impact on mental burden than the characteristics of the flood or the reconstruction process. Considering the strong impact of health status, health monitoring of affected populations may help identify individuals at greater risk, ensuring timely and targeted mental health interventions. These findings underscore the importance of incorporating long‐term psychosocial support into disaster recovery strategies.

Yanjie Sun, Xiaolong Song, Zhi Li et al.

This study introduces an innovative approach to modeling meandering river morphology, integrating and investigating the effects of geometric characteristics and vegetation-induced channel coarsening. The developed comprehensive framework combines several advanced techniques: Genetic Programming for refining the scour factor of transverse bed slope, a Leaf Area Index (LAI)-enhanced analytical model for quantifying vegetative flow resistance, and an upstream-weighted moving average method for efficient approximation of the convolution integral in meander migration calculations. The model is validated against both an idealized Kinoshita meander and a natural bend of the Tumen River (China) in equilibrium, demonstrating its robustness across diverse scales and conditions. The model's ability to simulate the long-term evolution, including cutoff events, provides valuable insight for river management strategies. The current findings demonstrate that channel geometry, particularly width-to-depth ratio, plays a dominant role in meander evolution, with wider channels prone to more complex and rapid morphological changes. Vegetation effects are most pronounced in channels with moderate width-to-depth ratios, where they can significantly influence migration rates and bed topography. A combination of channel widening and deepening, coupled with strategic vegetation management, can effectively enhance navigability while maintaining channel stability in the studied Tumen River reach. Sensitivity analyses highlight the complex interplay between hydraulic conditions, sediment characteristics, and vegetation in shaping river morphology. This research advances understanding of the multifaceted nature of meandering river systems and offers practical tools for informed decision-making in river engineering and environmental management, particularly in the context of climate change and increasing anthropogenic pressures on fluvial ecosystems.

Stefan Greiving, Stefanie Wolf, Daniela Michalski et al.

ABSTRACT The paper investigates which information on flood risk is needed for local land‐use planning and how a risk‐based planning approach can be implemented. The article is based on the results of a municipal consultation meeting at which German municipalities presented their planning cases in flood‐prone areas. These cases included the conversion of existing settlements and buildings and new developments on previously undeveloped land. The team of researchers conducted pluvial and fluvial flood risk assessments based on water depth and flow velocities and analyzed the planning documents. On this basis, we advised the municipalities regarding risk‐based planning. The flood event that hit the German states of Rhineland‐Palatinate and North Rhine‐Westphalia in mid‐July 2021 increased municipal awareness for flood‐sensitive planning. The consultation has confirmed that the biggest challenge is managing flood risk in existing built‐up areas. The extreme event changed the flood statistics and thus the assessment basis, but municipalities seek legal certainty for decision‐making. Currently, the lack of a clear planning basis creates uncertainty but also poses opportunities for change. In this context, we recommend, with reference to good examples from other European countries, an orientation towards the precautionary principle and the consideration of extreme flood scenarios.

Le Wang, Dayu Wang, Alan James Stewart Cuthbertson et al.

Flocculation of cohesive sediments is widely observed in natural aquatic-sedimentary environments, such as river estuaries and nearshore coastal waters, where salinity, suspended sediment concentration and flow turbulence cause fine sediment particles to aggregate into larger flocs, resulting in intensified sedimentation. In contrast, there is currently very little evidence linking enhanced sedimentation, leading to significant storage loss within large freshwater reservoirs, specifically to fine sediment flocculation processes. Massive fine sediment volumes have been deposited in the Three Gorges Reservoir (TGR), China, which has been impounded over the past two decades. It has not yet been established what role, if any, fine sediment flocculation processes play a role in the amplified sedimentation rates that have been observed. The current study aims to test the hypothesis that fine sediment flocculation processes, which occur under prevalent hydrodynamic (i.e., turbulent shear rate G ≈ 4.67–227.39 s−1) and sedimentary (i.e., sediment concentration C ≈ 0.02–2.00 kg/m3) conditions in the TGR, play important roles in sedimentation rates during reservoir impoundment. A laboratory-based, experimental study was conducted within a new, bespoke Couette flow system designed specifically to mimic the environmental shear flow conditions experienced during impoundment. Sediment samples obtained directly from the TGR bed deposits were tested within this facility to ascertain their flocculation and settling behavior under controlled shear flows and sediment concentrations. A comprehensive analysis combining the sediment composition, measured aggregate/floc size distributions and their corresponding settling behavior collectively pointed to the occurrence of fine sediment flocculation within the TGR. By disentangling the individual influences of flow velocity and sediment concentration on floc size, the combined influence of the flocculation parameters C/G1/2 on floc size is fully revealed through experimental evidence, with a new empirical combined parameter, C0.44/G0.47, identified as being more appropriate for characterizing the variability in floc size under varying flow‒sediment conditions. The majority of flocs measured in the tests have a mean settling velocity nearly five times greater than that of the majority of primary fine sediment particles (i.e., with diameter D ≤ 29 μm) that comprise the sediment grain size distribution found in the TGR impoundment. This finding provides new evidence for the potential for flocculation-enhanced sedimentation rates occurring within the TGR and other similar large freshwater reservoirs, as dam construction disrupts the natural sediment continuity within the river system and inhibits the downstream transport of fine sediments.

Kahsu Hubot, Haddush Goitom, Gebremeskel Aregay et al.

ABSTRACT Land use land cover (LULC) classification has been widely studied in remote sensing and GIS for agricultural, ecological, and hydrological processes. This study mainly focused on the prediction of the future impact of LULC change on peak stream flow through quantum GIS (QGIS) with the MOLUSCE plugin for LULC prediction, Geographical Information System (GIS) integrated with the HEC‐GeoHMS to prepare input data, and HEC‐HMS for hydrologic modeling. ERDAS IMAGINE was used to classify the watershed into six major LULC classes. Based on the Landsat image analyses for 1996–2016, the cropland area, built‐up area and vegetation had increased within two decades, and the annual rate of change was 0.11%, 0.83%, and 0.36%, respectively. However, forestland, shrubland, and bareland decreased at an annual rate of change of 0.26%, 0.21%, and 1.56%, respectively. The statistical downscaling model (SDSM) was used for the prediction of future rainfall of the Babur watershed, which helps to predict its future peak stream flow. The performance of the HEC‐HMS model was evaluated through sensitivity analysis, calibration, and validation. Both the calibration (1992–1998) and validation (1999–2001) results showed a good match between measured and simulated flow data with the coefficient of determination (R2) of 0.72, percent of bias (PBIAS) of 1.60%, root mean square error (RMSE) of 0.5, and Nash–Sutcliffe efficiency (NSE) of 0.774 for the calibration, and R2 of 0.86, PBIAS of −9.54%, RMSE of 0.4, and NSE of 0.842 for the validation period. Because of the change in LULC, the peak flow has increased by 19.33% and 45.91% during 1996–2016 and 2016–2036, respectively.

Salma Sadkou, Guillaume Artigue, Noémie Fréalle et al.

Abstract In a context of climate change, flash‐floods are expected to increase in frequency. Considering their devastating impacts, it is primordial to safeguard the exposed population and infrastructure. This is the responsibility of crisis managers but they face difficulties due to the rapidity of these events. The focus of this study was to characterize the extent of the link between hydrologists and crisis managers. It also aimed to determine the limiting and the fostering factors to an effective integration of forecasting in crisis management during flash‐floods. This was achieved through an extensive and methodological study of available literature in selected platforms. The models encountered were characterized on multiple levels including the physical, geographical and crisis management level. The results revealed a limited link between the two involved parties with limiting factors such as the complexity of the modeling approach, the insufficient projection in the implications of operationality of the models proposed and the financial aspect. On the other hand, acknowledging the threat of flash‐floods and conducting cost–benefit‐analysis were pinpointed as fostering factors. This study showed to reconsider the forecasting methods employed, particularly, the integration of machine learning, and the needs of end‐user in these applications in a crisis management context.

اشکان بنی خدمت, حسین صالحی, سعید گلیان et al.

مقدمه یکی از راه‌های برآورد مقدار رواناب حاصل از بارش، استفاده از مدل‌های هیدرولوژیکی است. مدل SWAT، یکی از ابزارهای پرکاربرد در سطح حوزه آبخیز در شبیه‌‌سازی کمیت و کیفیت آب است. این مدل، یک مدل مفهومی است که قادر است حوضه‌‌های بزرگ با سناریوهای مدیریتی مختلف را شبیه‌‌سازی کند. از جمله چالش‌های مهم مدل مذکور و بسیاری از مدل‌‌های هیدرولوژیکی، واسنجی پارامترهای موثر و حساس در برآورد مقدار رواناب است. به‌طور کلی، روش‌های واسنجی را می‌‌توان به دو گروه دستی و خودکار تقسیم کرد. واسنجی یک مدل به‌صورت دستی، نیازمند این است که مدل‌ساز، شناخت خوبی نسبت به فیزیک مد‌ل داشته باشد. از سویی، به‌دلیل وقت‌گیر بودن و پیچیدگی‌های موجود و همچنین، توسعه الگوریتم‌‌های جدید بهینه‌‌سازی، امروزه واسنجی خودکار بیشتر مورد توجه قرار گرفته ‌‌است. واسنجی خودکار بر پایه سه مولفه تابع هدف، الگوریتم بهینه‌‌سازی و اطلاعات ایستگاه‌ها بنا شده ‌‌است. استفاده از یک تابع هدف در واسنجی یک مدل ممکن است موجب افزایش خطا در برخی دیگر از جنبه‌های شبیه‌سازی شود و همچنین، تجربه‌های علمی در زمینه واسنجی تک‌‌هدفه نشان داده است که هیچ تابع هدفی هرچند با کارایی بالا، به تنهایی نمی‌‌تواند ویژگی‌ها و خصوصیات حوضه را به درستی نشان دهد. لذا، به‌‌کارگیری راه‌‌حل بهینه‌‌سازی مناسب به‌‌منظور بهبود نتایج واسنجی شامل استفاده از یک الگوریتم بهینه‌‌سازی مناسب با چندین تابع هدف، برای شناسایی مجموعه جواب‌‌های کارآمد است. مواد و روش‌‌ها حوزه آبخیز مورد مطالعه در غرب ایران و در استان کرمانشاه، با مساحت 5467 کیلومتر مربع، واقع شده است. کمینه و بیشینه ارتفاع آن، 1275 و 3360 متر است. متوسط بارندگی حوضه، حدود 505 میلی‌متر بوده است که بیشترین بارش در ماه‌های آبان و آذر و کمترین بارش در ماه‌های تیر و مرداد رخ می‌دهد و سه رودخانه اصلی مرک، قره‌سو و رازآور در این حوضه جریان دارند. در این پژوهش، مدل بارش-رواناب SWAT، با استفاده از الگوریتم‌ NSGA-II تحت سه سناریو واسنجی شد. برای واسنجی این مدل، در سناریوی اول، از تابع هدف NSE که به جریان‌‌های بیشینه توجه دارد، استفاده شد. در سناریوی دوم، برای تمرکز بر جریان‌‌های کمینه، پس از تبدیل لگاریتمی دو سری جریان رواناب شبیه‌‌سازی ‌‌شده و مشاهداتی، ضریب کارایی NSE به‌عنوان تابع هدف اتخاذ شد که به‌صورت LogNSE نمایش داده می‌‌شود. سناریوی آخر، تلفیقی از دو سناریوی اول و دوم بود. به‌‌طوری ‌‌که توابع هدف غیرهمسوی NSE و LogNSE به‌صورت همزمان مورد استفاده قرار گرفتند. نتایج و بحث نتایج این پژوهش، نشان داد که با توجه به مقادیر شاخص ارزیابی NSE برابر با 0.83، 0.74 و 0.83 برای سناریوهای اول تا سوم و بیش برآوردی مدل و بررسی نمودار جریان در سناریوی اول و تمایل بیشتر برای حرکت به سمت دبی‌‌های بالا، این سناریو برای برآورد جریان‌‌های بیشینه، کارآمدتر خواهد بود. همچنین، با توجه به شاخص ارزیابی LogNSE، مقادیر 0.69، 0.74 و 0.72 برای سناریوهای اول تا سوم، سناریوی دوم با تک هدف LogNSE در دبی‌‌های کمینه، عملکرد بهتری دارد. اما مدل ساخته شده با استفاده از دو تابع هدف غیرهمسو، سعی بر ایجاد توازن داشته است و عملکرد مطلوبی در تخمین همزمان رواناب‌های بیشینه و کمینه دارد. نتیجه‌گیری به‌طور کلی می‌توان گفت، در صورتی‌که هدف مطالعه بررسی دبی‌‌های بیشینه و کمینه، یعنی مطالعات سیلاب یا خشکسالی باشد، الگوریتم‌‌های تک ‌هدفه عملکرد مطلوب‌‌تری خواهند داشت. در صورتی‌که با هدف کنترل بیلان آبی و عملکرد مطلوب یک مدل در دو سوی دبی‌‌های بیشینه و کمینه، مدلسازی انجام شود، سناریوی دو هدفه با رویکرد غیرهمسو می‌‌تواند نتیجه بهتری نسبت به الگوریتم‌‌های تک هدفه داشته باشد.

مهسا تشکری, مهدی حیات زاده, علی فتح زاده et al.

مقدمهمهمترین مشکل در توسعه و ایجاد سدهای زیرزمینی، پیچیدگی تعیین مناطق مناسب احداث سد است. این مشکل از آنجا ناشی می‌‌شود که معیارها و عوامل زیادی شامل معیارهای اجتماعی، اقتصادی، زمین‌شناسی و هیدرولوژیکی در مکان‌یابی مناسب آن‌ دخیل هستند. لذا، استفاده از روش‌‌هایی که بتوانند مکان‌‌های مناسب برای احداث سدهای زیرزمینی را با دقت بالا و با صرف کمترین میزان وقت و هزینه تعیین نمایند، حائز اهمیت است. احداث سد زیرزمینی، به‌عنوان یکی از راه‌‌‌حل‌‌های تامین آب در مناطق خشک که امکان دسترسی به منابع معمول، نظیر چاه و رودخانه دایمی وجود ندارد یا دارای منابع آبی اندکی هستند، توصیه شده است. به همین منظور، در پژوهش حاضر مکان‌یابی مناطق مستعد برای احداث این‌گونه سدها مورد بررسی قرار گرفته است. محدوده مورد مطالعه، حوزه آبخیز رودان در استان هرمزگان است که به‌دلیل دارا بودن شرایط اقلیمی خشک و شرایط خاص زمین‌‌شناسی، می‌‌تواند از پتانسیل مناسبی برای ساخت سد زیرزمینی برخوردار ‌‌باشد.مواد و روش‌‌هادر پژوهش حاضر، از طریق تلفیق مدل رقومی ارتفاع، خصوصیات توپوگرافی، زمین‌‌شناسی و هیدرولوژیکی در محیط GIS، تعداد هشت مکان اولیه به‌‌عنوان نقاط مستعد احداث سد زیرزمینی مشخص شد. در ادامه، پس از تشکیل ماتریس تصمیم با استفاده از مدل ویکور، رتبه‌بندی، تعیین شاخص و انتخاب کوچک‌ترین شاخص به‌‌عنوان بهترین گزینه صورت پذیرفت. در نهایت، اقدام به مرتب‌سازی گزینه‌ها بر اساس مقادیر شاخص مطلوبیت، شاخص نارضایتی و شاخص ویکور شد. سپس، بهترین گزینه که کوچک‌‌ترین شاخص ویکور را داشته باشد، انتخاب شد.نتایج و بحثطبق نتایج به‌‌‌دست‌ آمده، مقدار شاخص ویکور (Q) برای سایت 5، عدد 0.0158 و برای سایت 2، عدد 0.097 به‌دست آمد که بدین ترتیب بر مبنای شاخص ویکور، رتبه اول متعلق به سایت 5 و رتبه دوم به سایت 2 تعلق گرفت. لذا، از بین هشت مکان اولیه تنها دو نقطه مناسب و سایر سایت‌‌های مستعد به‌علت فاصله از مراکز تمرکز جمعیتی و کشاورزی رد شدند. رتبه یک، واقع در شرق شهر زیارتعلی با توجه به شرایط هیدرولوژیکی و توپوگرافی از جمله این‌که شیب در این سایت کمتر از پنج درصد است، به‌‌عنوان یکی از بهترین مکان‌‌ها برای احداث سد زیرزمینی است. اولویت دوم، واقع در شمال بخش برنطین، به‌‌دلیل قرارگیری در مجاورت روستای کم جمعیتی که آب آشامیدنی از طریق چاه تامین می‌‌شود، به‌عنوان گزینه مناسب برای احداث سد زیرزمینی در نظر گرفته شد. در سایت‌‌هایی که اولویت اول و دوم را به خود اختصاص داده‌‌اند، از بین معیارهای مورد استفاده در پژوهش حاضر، معیارهای نیاز آبی، فاصله از روستا، پارامترهای pH و EC و کمیت آب، بیشترین اهمیت را داشته‌‌اند.نتیجه‌‌گیریبررسی نتایج عامل سطح مخزن در این پژوهش نشان داد که هر چه سطح مخزن بزرگ‌‌تر باشد، در مکان‌‌یابی این سازه دارای اولویت بیشتری خواهد بود. در سدهای زیرزمینی، بر خلاف سدهای سطحی که بزرگ بودن سطح مخزن به‌‌‌دلیل تلفات ناشی از تبخیر یک عیب محسوب می‌‌شود، بدون در نظر گرفتن سایر عوامل، بهترین مکان برای احداث سد زیرزمینی در یک رودخانه، تنگه‌‌هایی هستند که دارای بیشترین سطح مخزن در مناطق بالا‌‌دست جریان باشند. با نگاهی به محورهای انتخاب شده در پژوهش حاضر، مشاهده می‌‌شود که بالاترین اولویت‌‌ها و با ارزش‌‌ترین محورهای انتخابی در سازندهای کواترنر قرار گرفته‌اند که این نکته می‌‌تواند بیان کننده صحت مکان‌‌نمایی سازه باشد. از آنجا که اوج مصرف آب منطقه در فصول بهار و تابستان است، لذا، با احداث سد زیرزمینی در سایت‌های پیشنهادی می‌‌توان بخشی از کمبود و بحران آب در فصول گرم را جبران کرد.

Hèou Maléki Badjana, Hannah L. Cloke, Anne Verhoef et al.

Abstract Natural flood management (NFM) is widely promoted for managing flood risks but the effectiveness of different types of NFM schemes at medium (100–1000 km2) and large scales (>1000 km2) remains widely unknown. This study demonstrates the importance of fully understanding the impact of model structure, calibration and uncertainty techniques on the results before the NFM assessment is undertaken. Land‐based NFM assessment is undertaken in two medium‐scale lowland catchments within the Thames River basin (UK) with a modelling approach that uses the Soil and Water Assessment Tool (SWAT) model within an uncertainty framework. The model performed poorly in groundwater‐dominated areas (P‐factor <0.5 and R‐factor >0.6). The model performed better in areas dominated by surface and interflow processes (P‐factor >0.5 and R‐factor <0.6) and here hypothetical experiments converting land to broadleaf woodland and cropland showed that the model offers good potential for the assessment of NFM effectiveness. However, the reduction of large flood flows greater than 4% in medium‐sized catchments would require afforestation of more than 75% of the area. Whilst hydrological models, and specifically SWAT, can be useful tools in assessing the effectiveness of NFM, these results demonstrate that they cannot be applied in all settings.

Alexandre Ângelo Carmo Luiz daSilva, Julian Cardoso Eleutério

Abstract The main goal of this study is to identify the probability distribution of earthfill dam breach parameters using a dam failures database (3861 observations). This work looks to fill the lack of studies observed, using an extensive database instead of empirical models, plausible values, or small databases. It is, expected that this will contribute to the development of probabilistic dam breach inundation maps instead of deterministic mapping. Four parameters were selected: (i) side slope, (ii) height, (iii) width, and (iv) formation time. To identify the best‐fit distributions, a correlation analysis was performed and a comparative analysis was undertaken by groups related to dam and failure properties such as dam type, material erodibility, magnitude, failure mode, and others. These steps defined samples with 33–311 observations. The results demonstrate that dam breach parameters might be considered independent of each other and are affected by factors such as side slope by failure mode and bottom width by dam shape. The probabilistic case study indicated that deterministic dam breach models predominantly produce conservative results of breach peak outflow.

Yihong Shi, Jianwei Zhang

AbstractThis research comprehensively examined multiple sources of historical records and the built heritages of flood control construction along the Yongding River surrounding the Marco Polo Bridge section from 1890 to 1899, including stone levees, brick levees, cement dams, distributary channels, steel bridges, and temples dedicated to flood control. We mapped all these construction heritage features by time and geographical location according to historical documents to reveal the cause and intention behind each site. The following new insights were gained. First, the human–river relationship transitioned from utilization to resistance throughout the history of the Yongding River. Second, the philosophy of flood control represented a balance between symptom suppression and condition treatment at the peak of water management in imperial China. Third, the cultural and religious attitudes of humans in regard to flood control gradually shifted from a belief in the supernatural to faith in the ability of humans. Finally, modern technology, materials, and technicians were gradually imported, and water construction was implemented during the late Qing Dynasty, indicating modernization of the human–river relationship.

Suzhen Dang, Xiaoyan Liu, H. Yin et al.

The Yellow River is one of the rivers with the largest amount of sediment in the world. The amount of incoming sediment has an important impact on water resources management, sediment regulation schemes, and the construction of water conservancy projects. The Loess Plateau is the main source of sediment in the Yellow River Basin. Floods caused by extreme precipitation are the primary driving forces of soil erosion in the Loess Plateau. In this study, we constructed the extreme precipitation scenarios based on historical extreme precipitation records in the main sediment-yielding area in the middle reaches of the Yellow River. The amount of sediment yield under current land surface conditions was estimated according to the relationship between extreme precipitation and sediment yield observations in the historical period. The results showed that the extreme rainfall scenario of the study area reaches to 159.9 mm, corresponding to a recurrence period of 460 years. The corresponding annual sediment yield under the current land surface condition was range from 0.821 billion tons to 1.899 billion tons, and the median annual sediment yield is 1.355 billion tons, of which more than 91.9% of sediment yields come from the Hekouzhen to Longmen sectionand the Jinghe River basin. Therefore, even though the vegetation of the Loess Plateau has been greatly improved, and a large number of terraces and check dams have been built, the flood control and key project operation of the Yellow River still need to be prepared to deal with the large amount of sediment transport.