Flood modelling

Stretta è la relazione che corre tra lo svolgimento millenario della tecnica di lavoro dell'uomo, e i rapporti con l'ambiente naturale. L'uomo primitivo, come l'animale, raccoglie e consuma frutti spontanei colla semplice operazione prensile, e come l'animale fugge senza controllo davanti al dirompere del fenomeno naturale che ne minacci la vita. Come la produzione artificiale di prodotti pel consumo, e l'accumulazione di riserve di prodotti stessi e di utensili, lo costringe a fissarsi, così lo costringe a difendersi dalle minacce di meteore e sconvolgimento naturali. Una tale difesa, non diversamente da quella contro altri gruppi concorrenti alla sede migliore, o predatori della accumulata riserva, non può che essere collettiva. Da queste esigenze collettive, come tante volte vedemmo, nasce la divisione in classi e lo sfruttamento da parte dei dominatori.

In Marx, "il modo di produzione capitalistico presuppone il dominio dell'uomo sulla natura". Esso presuppone anche la guerra della natura contro l'uomo. Una troppo generosa e prodiga natura non sarebbe ambiente favorevole al sorgere del capitalismo.

In May 2014, extreme floods occurred in the lower Sava River basin, causing major damage, with catastrophic consequences. Based on the data gathered, the weather situation in Bosnia and Herzegovina's (BiH) Bosna River basin was analysed and the hydrological conditions were provided, including the results of the probability analysis of the size of the recorded precipitation and flow rates. A hydrological model of the Bosna River basin was developed using HBV-light for the purposes of reconstructing and forecasting such events more effectively. All analyses confirmed that the May 2014 event was an extreme event whose returning period greatly exceeds 100 years.

Flood related scientific and community-based data are rarely systematically collected and analysed in the Philippines. Over the last decades the Pagsangaan River Basin, Leyte, has experienced several flood events. However, documentation describing flood characteristics such as extent, duration or height of these floods are close to non-existing. To address this issue, computerized flood modelling was used to reproduce past events where there was data available for at least partial calibration and validation. The model was also used to provide scenario-based predictions based on A1B climate change assumptions for the area. The most important input for flood modelling is a Digital Elevation Model (DEM) of the river basin. No accurate topographic maps or Light Detection And Ranging (LIDAR)-generated data are available for the Pagsangaan River. Therefore, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Map (GDEM), Version 1, was chosen...

Abstract
Three key improvements to a widely used numerical model for predicting depth-averaged shallow water flows in estuarine and coastal waters are outlined herein. They include the adoption of a new grid layout for calculating friction and viscosity, a new method for simulating flooding and drying processes and a better representation of irregular wall boundaries. Although these improvements are currently implemented in the Depth Integrated Velocities And Solute Transport (DIVAST) model, they can easily be extended to other numerical models in the framework of a finite-difference or finite-volume method on a space-staggered rectangular grid system. Much effort has been made to keep the improvements simple and efficient so that they can be used in long-term and large-area simulations of estuarine and coastal flows. Numerical tests have been undertaken to verify the performance of these refinements for idealised bed forms, different beach configurations and irregular shoreline boundaries. The results show that for all conditions these refinements produce either the same or better results than the original model. Finally, the refined numerical model was used to simulate the tidal flow in a natural coastal basin. On the whole, the predicted variations in the inundation areas and the velocity fields were reproduced more accurately for different stages of the tide. At field measurement sites, the predicted water levels and velocities agreed favourably with the measured data.

Nowadays, floods events occur throughout the world and cause many negative impacts including agricultural production, loss of lives and property damage. In Rwanda agricultural activity, occupy around 90% of all economic activities and every year natural disaster like draught and flood affect agricultural production. In heavy rain, people lost their crops due to the destruction of their blocks of lands. The huge number of flood hazards of today has different driving factors. Recently, Rwabashyashya marshland has suffered the high extent-flooding problem did not happened before , probably as a result of heavy rainfall, steep slopes and land use/land cover change. The main aim of this work is to contribute to flood management in Rwabashyashya marshland through the assessment of driving factors of floods from Rwabashyashya sub catchment (26.63724 km2) in Kamonyi district southern Rwanda. Interviewing survey and field visits were used for historical flooding. ARGIS 10.4 used a Digital Elevation Model (DEM) to delineate the watershed and to produce watershed slope map. The generated land use maps were used to detect land use/land cover change and also the land cover types were adopted to estimate the runoff coefficient of the sub catchment to calculate a weighted runoff coefficient. The rainfall intensity was determined using the rainfall data obtained from Gacurabwenge meteorological station that is near (5 km) the marshland and considering the time of concentration. The catchment profile and empirical formulae were used to compute the time of concentration. A simple rational formula method with area correction was used to estimate the total discharge from the catchment. Manning formula was adopted to determine the hydraulic discharge of the natural stream channel. The results show that agricultural land use dominates in the sub catchment with about 60.38% in 2016 and the built up area show rapid increase from 0.487 ha to 538.68 ha in 2008 and 2016 respectively. The weighted runoff coefficient was found to be 0.39, the time of concentration was determined to be 0.896 hour for the whole watershed and the hydrological flow rate was estimated to be 204.29m3/s. Hydraulic discharge was found to be 4.83m3/s and which is too less for channel to handle the hydrological discharge. Based on the results obtained, we can draw conclusion that the main contributors to floods in Rwabashyashya marshland are land use/land cover change (increased impervious surfaces), heavy rainfall and the steep slope of the area which is ranging from 1506m to 1904m. Some floods management measures were proposed. To sum up, this research generated should be transferred to other Rwandan marshlands to decide measures of protection floods and as well integrated flood management in order to contribute to the achievement of sustainable development of the-country.

Keywords: Rwabashyashya Marshland, flood management, driving factors, land use/land cover change, sub catchment, measures.

Durante el evento hidrometeorológico extremo de marzo 2015 más de 50 mm precipitaron en el Desierto de
Atacama (Chile). Las intensas lluvias causaron daños en varias ciudades de la Región de Atacama. La ciudad de
Copiapó se encuentra en la confluencia entre el Río Copiapó y Quebrada Paipote, un afluente seco en condiciones
climáticas normales. El proceso involucró un flujo de fango muy rápido (2,5 – 5,5 m/s) de alta densidad y viscosidad
que arrastró un gran volumen de arena y lutitas y enterró la ciudad bajo una capa de 31 cm de espesor medio. Un área
total de 12,2 km2 se inundó, el 72% de la zona urbana. Se han identificado cuatro sectores en los que se superaron los 2
m de inundación, con una medida máxima de 3,8 m cerca de la confluencia de los dos cauces y una inundación media
de 45 cm para toda la ciudad. El volumen de sedimento acumulado se estima aproximadamente en 2,2 millones m3 que
rellenaron casas, sótanos, alcantarillado, etc. Este evento pone de manifiesto la necesidad de elaborar mapas de
peligrosidad que combinados con análisis de vulnerabilidad permitan evaluar el riesgo de inundación de la ciudad.

Abstract The flooding in Bangladesh during monsoon season is very common and frequently happens. Consequently, people have been experiencing tremendous damage to properties, infrastructures, and human casualties. Usually, floods are one of the devastating disasters from nature, but for developing nations like Bangladesh, flooding becomes worse. Due to the dynamic and complex nature of the flooding, the prediction of flooding sites was usually very difficult for flood management. But the artificial intelligence and advanced remote sensing techniques together could predict and identify the possible sites, which are vulnerable to flooding. The present work aimed to predict and identify the flooding sites or flood susceptible zones in the Teesta River basin by employing state-of-the-art novel ensemble machine learning algorithms. We developed ensembles of bagging with REPtree, random forest (RF), M5P, and random tree (RT) algorithms for obtaining reliable and highly accurate results. Twelve factors, which are considered as the conditioning factors, and 413 current and former flooding points were identified for flooding susceptibility modelling. The Information Gain ratio statistical technique was utilized to determine the influence of the factors for flooding. We applied receiver operating characteristic curve (ROC) for validation of the flood susceptible models. The Freidman test, Wilcoxon signed-rank test, Kruskal–Wallis test and Kolmogorov–Smirnov test were applied together for the first time in flood susceptibility modelling to compare the models with each other. Results showed that more than 800 km 2 area was predicted as the very high flood susceptibility zones by all algorithms. The ROC curve showed that all models achieved more than 0.85 area under the curve indicating highly accurate flood models. For flood susceptibility modelling, the bagging with M5P performed superior, followed by bagging with RF, bagging with REPtree and bagging with RT. The methodology and solution-oriented results presented in this paper will assist the regional as well as local authorities and the policy-makers for mitigating the risks related to floods and also help in developing appropriate measures to avoid potential damages. Graphic abstract

Akarsular, evsel tüketim, tarımsal sulama ve endüstri için gerekli olan suyun karşılanmasında, ayrıca uygun taşıma yolları, sürdürülebilir enerji ihtiyacı ve tüm canlıların doğal yaşamları için vazgeçilmez en önemli su kaynaklarından birisidir. Akarsulardan sadece yararlanmak için değil aynı zamanda olası zararlarından korunmak içinde gerekli mühendislik çalışmalarının yapılması oldukça önemlidir. Bu amaçla inşa edilen baraj, sedde, regülatör, köprü, menfez, savak ve taşkın koruma yapılarının su yüzü profillerine etkisinin değerlendirilmesi, planlama, uygulama, işletme mühendisleri için ve ayrıca taşkın sigortalama çalışmaları içinde gereklidir. Su yapılarının projelendirilme ve ekonomik analiz çalışmaları yoğun hesaplama ve tekrarlı yöntemler içermektedir. Günümüzde gelişen, daha büyük ve karmaşık hale gelen bu projelerdeki hesaplamaların hızlı ve doğru bir şekilde yapılabilmeleri için bilgisayar kullanımı kaçınılmaz olmaktadır. Su yapıları mühendislik uygulamaları için geliştirilmiş, hesap ve analiz kolaylığı sağlayan birçok paket program bulunmaktadır.
Bu programlardan birisi de Amerika Birleşik Devletleri Askeri Mühendislik birimi tarafından geliştirilen HEC-RAS (Hydrologic Engineering Centers River Analysis System), paket programıdır. HEC-RAS paket programı doğal akarsular ve sonradan inşa edilmiş açık kanallardaki akımların bir boyutlu hidrolik hesabını gerçekleştirmek üzere geliştirilmiş grafik tabanlı, kapsamlı bir yazılımdır. Program düzenli ve değişken akımlarda su yüzü profili hesaplamaları, sediment taşınım/hareketli taban hesaplamaları, su kalitesi analizleri ve birçok hidrolik yapı hesaplamaları yapabilmektedir. HEC-RAS paket programı http://www.hec.usace.army.mil/software/hec-ras/ sitesinden ücretsiz olarak indirilebilmekte ve kullanılabilmektedir. Sitede ayrıca program hakkında detaylı bilgi veren yardımcı dokümanlara ulaşılabilmektedir. Bunlardan en önemlileri kullanım kılavuzu “User’s Manual”, hidrolik hesap yöntemlerini açıklayan “Hydraulic Reference Manual” ve uygulama örnekleri ve açıklamalarını içeren “Applications Guide” dır.
Bu kitapta HEC-RAS programında kullanılan açık kanal akımlarına ait hidrolik hesaplama yöntemleri ve bazı örnek uygulamalar ele alınmıştır. Ayrıca bir laboratuvar kanal modeli üzerindeki farklı su yapılarına ait geliştirilen uygulamalar ve gerçek bir taşkın düzenleme yapısına ait örnek paylaşılmıştır.
Bu kitap altı bölümden oluşmaktadır. Birinci bölümde HEC-RAS paket programı hakkında genel bilgiler verilerek, hesaplamalarda kullanılan denklemler açıklanmıştır (Hydraulic Reference Manual, Chapter 2). Ayrıca program ara yüzü ve kullanımı detaylı olarak ele alınmıştır (Hydraulic Reference Manual, Chapter 3). Birinci bölümde program uygulama dosyasındaki (Application Guide, Chapter 1) eğimli dere (Örnek 1) ve ayrıca laboratuvar kanalının modellenmesine ait bir çalışma (Örnek 2)açıklanmıştır. Bu bölümde ayrıca Application Guide, Chapter 8 de verilen kapalı göz oluşturan nehir örneği (Örnek 3) ve yine aynı kaynakta Chapter 10 da verilen kesişen akarsu kollarına ait örnek (Örnek 4) ele alınmıştır.
İkinci bölümde köprü yapılarının HEC-RAS ile nasıl modelleneceği, kullanılan denklemler ve yaklaşımlar (Hydraulic Reference Manual, Chapter 5) açıklanmış, Application Guide, Chapter 2 de verilen tek açıklıklı köprü örneği (Örnek 5) ele alınmıştır. Bu bölümde ayrıca laboratuvar kanalı üzerinde bulunan tek ve iki açıklıklı köprü yapısının nasıl modelleneceği açıklanmıştır (Örnek 6).
Üçüncü bölümde menfez yapılarının HEC-RAS da modellenmesi, kullanılan denklemler ve yaklaşımlar (Hydraulic Reference Manual, Chapter 6) açıklanmış, Application Guide, Chapter 3 de verilen, benzer varilli tek menfez örneği (Örnek 7) ve aynı kaynakta bulunan (Chapter 4) çoklu menfezler Örnek 8 de ele alınmıştır. Bu bölümde ayrıca laboratuvar kanalı üzerinde bulunan tek menfez çoklu varillerin nasıl modelleneceği Örnek 9 da açıklanmıştır.
Dördüncü bölümde HEC-RAS ile bir kesitte çoklu köprü ve/veya menfez açıklıklarının modellenmesi (Hydraulic Reference Manual, Chapter 7) ele alınmıştır. Application Guide, Chapter 5 de verilen çoklu açıklıklar örneği (Örnek 10), Chapter 7 de verilen çoklu plan örneği (Örnek 11) ve yine aynı kaynak Chapter 9 da verilen karışık akım analiz örneği (Örnek 12) açıklanmıştır.
Beşinci bölümde kapaklı savak, sedde ve düşü yapılarının modellenmesi (Hydraulic Reference Manual, Chapter 8) ele alınmıştır. Application Guide, Chapter 12 de verilen enkesit yapıları örneği (Örnek 13) ayrıca laboratuvar kanalı üzerinde bulunan geniş başlıklı savak ve yan savak yapılarının nasıl modelleneceği açıklanmıştır (Örnek 14).
Altıncı bölümde ise taşkın koruma yapılarının su yüzü profillerine etkisi (Hydraulic Reference Manual, Chapter 9) ele alınmıştır. Application Guide, Chapter 6 da verilen taşkın kanalı hesaplamalarına ait örnek (Örnek 15) ve yine aynı kaynak Chapter 16 da verilen kanal düzenlenmesi örneği (Örnek 16) açıklanmıştır. Son olarak Örnek 17 de Kayseri, Talas ilçesinde bulunan Deliçay taşkın deresinin hidrolik modellemesi yapılmıştır.
Bu kitabın su yapıları konularında çalışan akademisyenler, planlama ve uygulama mühendisleri ve özellikle su kaynaklarına ilgi duyan inşaat mühendisliği lisans ve lisansüstü öğrencilerine yararlı olmasını dilerim. Akademik hayatımda bana her zaman destek ve rehber olan saygı değer hocam Prof. Dr. M. Salih KIRKGÖZ’e sonsuz teşekkürlerimi sunarım. Kitap üzerindeki olası öneri, eleştiri ve hataların iletilmesi durumunda daha faydalı bir kaynak olacağı düşüncesiyle, hayırlı olmasını diliyorum.

Abstract
Dam-break flows usually propagate along rivers and floodplains, where the processes of fluid flow, sediment transport and bed evolution are closely linked. However, the majority of existing two-dimensional (2D) models used to simulate dam-break flows are only applicable to fixed beds. Details are given in this paper of the development of a 2D morphodynamic model for predicting dam-break flows over mobile beds. In this model, the common 2D shallow water equations are modified, so that the effects of sediment concentrations and bed evolution on the flood wave propagation can be considered. These equations are used together with the non-equilibrium transport equations for graded sediments and the equation of bed evolution. The governing equations are solved using a matrix method, thus the hydrodynamic, sediment transport and morphological processes can be jointly solved. The model employs an unstructured finite volume algorithm, with an approximate Riemann solver, based on the Roe-MUSCL scheme. A predictor–corrector scheme is used in time stepping, leading to a second-order accurate solution in both time and space. In addition, the model considers the adjustment process of bed material composition during the morphological evolution process. The model was first verified against results from existing numerical models and laboratory experiments. It was then used to simulate dam-break flows over a fixed bed and a mobile bed to examine the differences in the predicted flood wave speed and depth. The effects of bed material size distributions on the flood flow and bed evolution were also investigated. The results indicate that there is a great difference between the dam-break flow predictions made over a fixed bed and a mobile bed. At the initial stage of a dam-break flow, the rate of bed evolution could be comparable to that of water depth change. Therefore, it is often necessary to employ the turbid water governing equations using a coupled approach for simulating dam-break flows.

Ce rapport contient le Plan de réduction du risques d'inondation de Tallé, un village administratif de la commune rurale de Gothèye, région de Tillabéri, Niger. Tallé (2 603 habitants en 2012, 0,5 km2 de surface bâtie en 2019) est situé le long de la rivière Sirba, près de la confluence avec le fleuve Niger. Le village est menacé par les inondations fluviales. Le plan est structuré selon l’ISO 31010. L’analyse intègre les connaissances locales et scientifiques. Le processus de planification est entièrement participatif. Les risque d’inondation est identifié et analysé. Les zones inondables suite au débordement de la Sirba et de reflux du fleuve Niger sont identifiées en fonction de trois scénarios de probabilité d’occurrence grâce à une modélisation hydraulique 1D. Les enjeux sont identifiés après une reconnaissance systématique de terrain. Huit mesures de réduction du risque sont sélectionnées et classées par ordre de priorité. L’analyse bénéfice/coût est utilisée pour évaluer l’intérêt de traiter ou d’accepter le risque. Le dispositif de suivi-évaluation est décrit. Le plan comprend règlement des zones inondables, le zonage règlementaire, les cartes des aléas et des enjeux, ainsi que des fiches décrivant chaque action prioritaire. --- (ENGLISH) This report contains the Flood Risk Reduction Plan for Tallé, an administrative village of the rural municipality of Gothèye, Tillabéri region, Niger. Garbey Kourou (2603 inhabitants in 2012, 0.5 km2 of built up area in 2019) is located along the Sirba River, close to the confluence with the Niger River. The village is threatened by fluvial floods. The plan is structured according to the ISO 31010. The analysis integrates local and scientific knowledge. The planning process is fully participatory. Flood risk is identified and analyzed. Areas inundated by the flood of the Sirba river and the backwaters of the Niger river are identified according to three river flood probability of occurrence scenarios through a 1D hydraulic modeling. Floodable assets are identified through a systematic field survey. Eight risk reduction actions are selected and prioritized. Benefit/cost analysis is used to assess the convenience of treating or accepting the risk. The monitoring and evaluation system is described. The plan consists of the flood zone regulation, hazard, assets, and zoning maps, and sheets describing each priority action.

Abstract
A simple TVD (Total Variation Diminishing) step is appended to the standard MacCormack scheme for simulating shallow water dynamics.  The governing equations are solved on a uniform Cartesian grid system.  Two forms of the conservative SWEs (Shallow Water Equations) were compared for inclusion in the computations.  The comparisons showed that the numerical solutions gave more accurate predictions when the water level was chosen as one unknown parameter, rather than the water depth.  The TVD-MacCormack model was then compared with a widely used numerical model which employs the traditional ADI (Alternating Direction Implicit) method to predict shallow water flows.  This traditional model was unable to predict trans-critical flows under normal conditions and artificial viscosity had to be introduced to remove the spurious oscillations occurring near sharp gradients, while the TVD-MacCormack model was able to recognize and reproduce all flow regimes accurately with no adjustable parameters.  Finally, a dyke-break experiment was used to verify the TVD-MacCormack model.  The computed results compared favourably with the experimental results.

Floods are among the most destructive natural disasters, which are highly complex to model. The research on the advancement of flood prediction models contributed to risk reduction, policy suggestion, minimization of the loss of human life, and reduction the property damage associated with floods. To mimic the complex mathematical expressions of physical processes of floods, during the past two decades, machine learning (ML) methods contributed highly in the advancement of prediction systems providing better performance and cost-effective solutions. Due to the vast benefits and potential of ML, its popularity dramatically increased among hydrologists. Researchers through introducing novel ML methods and hybridizing of the existing ones aim at discovering more accurate and efficient prediction models. The main contribution of this paper is to demonstrate the state of the art of ML models in flood prediction and to give insight into the most suitable models. In this paper, the literat...

Doğal afetlerin önüne geçebilmek mümkün olmasa da, yıkıcı etkilerini azaltarak can ve mal kaybını en aza indirmek günümüz bilgi ve teknolojileri ile sağlanabilmektedir. Artan nüfus ve sanayinin gelişimine bağlı yüksek sera gazı salınımları, iklim değişikliği tehlikesini de beraberinde getirmiş, bu değişime bağlı su kaynaklarının yönetimi daha da önemli hale gelmiştir. Akarsu yatağının su iletim kapasitesinin çeşitli sebeplerle azalması veya kapasiteden daha fazla suyun gelmesi halinde yatak dışına taşarak can ve mal kaybına sebep olan taşkınlar, tedbir alınması gereken önemli afetlerdendir. Taşkınlar yerleşim alanlarına, altyapı tesislerine, tarım arazilerine, insanların sosyal ve ekonomik hayatlarına, önemli zararlar verebilmektedir.
Amerika Birleşik Devletleri Askeri Mühendislik birimi tarafından geliştirilen HEC-RAS (Hydrologic Engineering Centers River Analysis System), paket programı, 2017 yılında yayınlanan AÇIK KANAL AKIMLARI ve HEC-RAS UYGULAMALARI kitabımda örnek uygulamalar ile ele açıklanmıştır. Programın güncel 5.X sürümlerinde bir boyutlu (1D) modelleme özelliğinin yanı sıra iki boyutlu (2D) akım modelleme özelliği eklenmiştir. Programda ihtiyaç duyulan arazi topoğrafik ve morfolojik bilgilerine, uydu verileri ve hava fotoğrafları kullanılarak ulaşılabilmektedir. Topoğrafyanın sayısal gösterimi olan Sayısal Yükseklik Modeli–SYM, (Digital Elevation Model-DEM), günümüzde, SRTM, ASTER, LANDSAT gibi uydu verileri ile üretilebilmektedir.
Yeni sürümlere eklenen HEC-RAS Mapper özelliği ile program, açık kanal akımlarında çok amaçlı hesaplamaları birlikte gerçekleştirebilecek kapasitede tasarlanmış bütünleşik bir yazılım sistemidir. Program grafik tabanlı ara yüz ile düzenli akım su yüzü profil hesaplamaları, bir (1D) ve iki boyutlu (2D) değişken akım modellemeleri, yarı ve tam değişken akım katı madde taşınım modellemeleri ve su kalite analizlerini gerçekleştirebilmektedir. Sonuçların tablo ve grafiksel olarak görüntülenmesi, taşkın yayılma haritalarının oluşturulması ve animasyonu, raporlanması ve depolanması yapılabilmektedir.
Bu çalışmamda, programın güncel sürümlerine eklenen HEC-RAS Mapper modülü açıklanarak 1D modellemenin yanı sıra 2D taşkın modelleme ve 1D/2D birleşik taşkın modelleme uygulamaları ele alınmıştır. Kitabın ilk bölümünde iki boyutlu akım modelleme özellikleri, avantajları ve kısıtları açıklanmıştır. İkinci bölümde 2D modelleme için gerekli arazi modellerinin geliştirilmesi, üçüncü bölümde 1D/2D birleşik model geliştirilmesi, dördüncü bölümde birleşik modelin çalıştırılması, beşinci bölümde sonuçların RAS Mapper ile görüntülenmesi açıklanmıştır. Altıncı bölümde düzenli akım modellemesine ve değişken akım modellemesine ne zaman ihtiyaç duyulacağı, 1D nehir kolu ve 2D akım alanı veya depolama alanlarının nerede kullanılacağı konuları ele alınmıştır. Yedinci bölümde örnek uygulamalarda ele alan Çamaşırcı deresi ve taşkın debileri hakkında bilgiler verilmiştir.
Çamaşırcı deresinde iki farklı periyottaki (Q25 ve Q100) taşkın debileri için düzenli ve değişken akım analizleri gerçekleştirilmiştir. Uygulama 1 de Çamaşırcı deresi ve yan kolu olan Baruthane deresi doğal kesiti, 1D olarak modellenmiştir. Uygulama 2 de Çamaşırcı deresi düzenlenmiş mevcut kanal durumunda sanat yapıları (köprü ve menfezler) dikkate alınmadan 1D olarak modellenmiştir. Uygulama 3 de Çamaşırcı deresi düzenlenmiş mevcut kanal durumu, köprü ve menfezler dikkate alınarak 1D olarak modellenmiştir. Uygulama 4 de mevcut duruma taşkın koruma amaçlı bir kapak yerleştirilerek düzenli ve değişken akım analizleri gerçekleştirilmiştir. Uygulama 5 de Çamaşırcı deresinde iki boyutlu (2D) değişken akım analiz yapılarak taşkın sınırları belirlenmiştir. Son olarak Uygulama 6 da Çamaşırcı deresinde 1D/2D birleşik akım analizi yapılarak taşkın sınırları belirlenmiştir.
Uygulamalarda ele alınan Çamaşırcı deresine ait bilgiler, 2019 yılında Gezer Endüstri İnşaat ve Tic. A.Ş. için hazırlanan, “İstanbul Çamaşırcı Deresinin HEC-RAS ile Taşkın Analizi ve Çözüm Önerileri Raporu” kapsamında yapılan ölçüm ve incelemelerden alınmıştır. Bu vesile ile arazi ölçümlerinde yardımcı olan firma yetkililerine ve özellikle Makine Mühendisi Suat BALAMİR beye teşekkürlerimi arz ederim.
Bu yeni kitabımın su yapıları konularında çalışan akademisyenler, planlama ve uygulama mühendisleri ve özellikle su kaynaklarına ilgi duyan inşaat mühendisliği lisans ve lisansüstü öğrencilerine yararlı olmasını dilerim. Kitap üzerindeki olası öneri, eleştiri ve hataların iletilmesi durumunda daha faydalı bir kaynak olacağı düşüncesiyle, hayırlı olmasını diliyorum.

This study used SWMM model to simulate the urban flood in Vijayawada. IDF curves for return period of 1 year and 2 years is
prepared along with LULC map using Sentinel data. Then model setup for historical extreme event for 2018 is done and then used for future
climate data of GCM for RCP 4.5 scenario. The result shows that few nodes are flooded in the region and there are some overflow sections.
The overflow in the section and nodes were due to heavy rainfall and imperviousness of the sub catchment. This type of study is helpful to
assess the future floods, mitigate the risk of urban flooding and helpful for policy makers for the designing of adequate urban drainage system
in developing cities.

The developed model 'Drip Chartist' by Ismail et al. (2006a) was verified and validated in field and by comparison to other related model "Hydrus 2D". Field validation resulted showed that the surface system without hydraulic barrier represents the real-condition by 94.99% (correlation coefficient of 0.9746) with under estimation of 0.157. While in the subsurface system with hydraulic barrier represents the realcondition by 81.96% (correlation coefficient of 0.9053) with under estimation of 0.021. Validation to Hydrus2D lead to almost coincidence in predicted values of wetting pattern. Several studies were performed using the model, like studying soil properties such as θsat, θres, Ks, and the retention and conductivity parameters of soil such as α, m, n, λps, and ϒ effect on soil moisture pattern. The effect of soil texture indicated that the heavy textured soils could be simulated faster than light texture soils, while silt texture soil was simulated in longer time compared to other texture classes, solution methods, and other properties were studied as well. In addition, some construction alternatives of the system were studied like the effect of bilateral gap, dripper line burying depth, physical barrier and the emitter discharge on the wetting pattern. The model "Drip Chartist" was proved to act like intended in predicting surface and subsurface drip wetting pattern.

Floods are amongst the most destructive natural hazards cause lots of economic damages and casualties. Advancements in Remote Sensing and computer sciences provide a great opportunity for researchers to implement flood prediction systems to mitigate devastating impacts of flood events. In the following research, total outflow, peak flow and time to peak for runoff within the Siahroud watershed in Mazandaran, a northern province of Iran, has been simulated using remote sensing, GIS and The Hydrologic Modeling System (HEC-HMS). For this reason, Basin model has been extracted from DEM in GIS as an import data for HEC-HMS model. In order to estimation of Curve Number (CN), Land Use and Land Cover data extracted from Landsat 8 OLI using object-based classification method were combined with Soil Hydrological groups. In next step, time series data include hydrologic and rainfall data from six floods events were added to the modeling software. These six events were divided in two groups. Three events used for calibration of the model and three other events for validation. Validation results showed a good correlation for peak flow and time to peak in observed and simulated hydrographs while the difference between observed and computed outflow in two events revealed a limitation in simulation of total discharge.

In this study, water rising due to the flood which is at Akkışla Bridge located at Ova Creek was analyzed using a river analysis software program, HEC-RAS. Unsteady flow simulations were performed using different flood hydrographs and it is observed that the free surface flow level rises above the bridge deck for 500-year flood discharge. Three different flood control types which are taking the peak discharge to flood retarding pool via the side weir, changing the slope of the river and changing the river cross section were applied and their results were compared. It is obvious that the maximum level of water surface at bridge cross section can be reduced 1.5 m by changing river morphology. According to the results of analyses, applicability of these three flood control types were discussed. The most appropriate flood control method was suggested, these three flood control methods were compared in terms of economy.
Keywords: Flood, Side Weir, River Morphology, HEC-RAS

Flood risk assessments and damage estimations form integral parts of the disaster risk management in Jamaica, owing its vulnerability to hydrometeorological hazards. Although island wide damage and risk assessments have been carried out for major flood events in Jamaica, few studies have been conducted for the creation of damage and risk maps for vulnerable areas. In this study, a risk-based tool was developed by transferring a proven methodology for flood risk assessment in Flanders, called LATIS, to areas with limited data resources. The town of Annotto Bay was chosen as case study due to its vulnerability to coastal and riverine flooding. The model uses input parameters such as flood data, land use, and socioeconomic data and rainfall values to estimate the damage. The flooding of 2001, caused by tropical storm Michelle, as well as a storm surge with a 100-year return period, was input for the model in order to estimate damage from fresh and saltwater for Annotto Bay. The produced maps show the spatial variation of the damage costs, which correlates with the flood depths. The total calculated damage cost from the freshwater flood of 2001 in the study area was estimated just over USD 7 million. Saltwater damages were calculated at USD 30 million. Although validation of the exact damage costs was not possible, the damage spread and number of affected elements were accurate. The model output also shows the potential number of people who would be killed as a result of the event, which was calculated at only 2 casualties for freshwater. Since in reality no one died, this low estimate can be considered accurate. The casualties caused by the saltwater flooding with a return period of 100 years were estimated at 150 people killed. The results of this approach can be extended to other vulnerable areas of the island having topographical and geographical similarities and being affected by similar hydrometeorological events. Hence, the method allows damage assessment for data-sparse regions, aiding in planning and mitigation measures for flood-prone communities.

Floods are probably the most recurring, widespread, disastrous and frequent natural hazards of the world. India is one of the worst flood-affected countries. In India the Himalayan Rivers account for maximum flood damage in the country. The problem of flood in the state of Odisha is well known and every year it becomes a recurring problem to the entire region. The plains of Orissa are some of the most susceptible areas in India, prone to flooding. Recent studies strongly suggest the possibility of more frequent extreme events as a result of the changing climate. These weather extremes, such as excessive rainfall, result in debris flow, river overflow and urban flooding, which can pose a substantial threat to the community. An effective flood model is therefore a crucial tool in flood disaster control and mitigation. A number of flood models have been established in recent years. However, the major challenge in developing effective and accurate flood models is the disadvantage of running multiple models for separate, individual conditions. Among the solutions in recent research is the development of hydrologic and hydraulic modelling. Coupled of both modelling approach allows the channel flows to be represented in 2D. In order to test the efficiency of the approach, this research aims to assess the capability of the U.S. Army Corps of Engineers Hydrologic Engineering Center River Analysis System (HEC-RAS) model’s implementation of the 2D hydraulic computation in simulating river overflow inundation. Time series analysis of hydrological data has been done to look for the rainfall and runoff behaviour in Tel Basin and their cross-correlation. SRTM-DEM of 30m resolution is used to generate the various maps (DEM) of Tel Basin. Hydrological and hydraulic models Arc GIS, Arc Swat and HEC-RAS, models are used for runoff and floodplain inundation modelling.
The flood inundation simulation for the Tel River floodplain is carried out using HEC-RAS 2-D hydrodynamic model indicates promising results. Further, linear/non-linear regression models were developed to estimate the flood inundation area provides best results.

The flood frequency analysis is a way of finding the number of occurrences and identification of largest flood for a certain period. On the other hand, the flood frequency analysis is a means of shorting out the flood events of a particular river or rivers of a geographical area of importance. There have been various methods of analysis which provided good results in flood forecasting with little variation depending on range of the data set. The article has been prepared based on two sets of hydrological data such as annual peak discharge and water level; which have been collected from Brahmaputra Board and Water Resources Department, Govt. of Assam. Here we have presented a comparative analysis of flood frequency of the Puthimari River in Assam. The analysis has been done based on the water discharge, water level or stage (maximum, minimum and danger level). The hydrograph, Log-Normal and Log-Pearson Type III methods have been deployed in MS Excel sheet to make a comparison of flood events from 1955 to 2008 and 1953 to 1993 respectively. The results show that there have been two mega floods during this period of time while the estimated flood discharges of Log-Normal and Log Pearson Type III methods show hardly any difference for the Puthimari River Basin.

The fact that, in the Ozana drainage basin, most of the people have built their homes in the river valley, determines that a study focused on identifying the areas exposed to
hydrological risk is vital, mostly in the development decisions for villages and in the creation of management plans for emergency situations. This study analyses the mapping methodology of the flood prone areas in the middle and lower sector of the Pluton river, which is a tributary of Ozana river, in its upper sector. In order to correctly draw the flood risk maps, the HEC-RAS method has been used, together with the HEC-GeoRAS extension, in ArcGIS. The results that have been obtained, correlate with the field situation in a very high proportion: for a 1% occurance flood, almost 123 households have been damaged, and according to the
simulation, a number of 147 buildings have been damaged, therefore other probabilities (that overcome the 1% situation) can be used for similar simulations.

ABSTRAK Kota Samarinda terletak pada SubDAS Karang Mumus dan memiliki sungai utama yaitu Sungai Karang Mumus. Sungai Karang Mumus sendiri merupakan muara dari anak-anak sungai pada SubDAS Karang Mumus dan menjadi muara dari saluran-saluran drainase Kota Samarinda. Permasalahan banjir di Samarinda karena adanya indikasi ketidakmampuan sungai Karang Mumus dalam mengalirkan debit yang berasal dari subsub DAS pada SubDAS Karang Mumus. Untuk menanggulangi hal tersebut Pemeritah Kota Samarinda telah berupaya dengan membangun Waduk Benanga sebagai pengendali banjir, namun berdasarkan data pengukuran tahun 2001 dan 2010 terdapat penurunan kapasitas tampungan dari waduk Benanga, sehingga hal ini juga memiliki indikasi menjadi penyebab banjir pada Sungai Karang Mumus (SKM). Oleh karena itu, pada penelitian ini akan dilakukan pendekatan penanggulangan banjir dengan beberapa alternatif pengendalian banjir. Analisa debit banjir pada penelitian ini menggunakan metode SCS Curve Number pada HEC-HMS dan analisa profil muka air sunga menggunaka Unsteady Flow Analysis pada HEC-RAS. Hasil analisa penanggulangan banjir diketahui bahwa penurunan kapasitas tampung waduk tidak berpengaruh signifikan, terbukti saat dilakukan normalisasi waduk, nilai reduksi debit banjir yang dihasilkan hanya 13%. Setelah upaya normalisasi waduk tidak menunjukkan hasil yang baik, maka dilakukan upaya dengan menggunakan bangunan pengendali banjir (Bendali). Hasil analisa menggunakan 6 Bendali rencana dan tambahan 4 potensi Bendali baru menunjukkan peningkatan nilai reduksi yang mencapai angka 50%. Dari nilai reduksi yang cukup baik, tinjauan dilakukan pada profil muka air bagian hilir. Hasil analisa menunjukkan pasang-surut Sungai Mahakam berpengaruh signifikan dalam perubahan muka air bagian hilir, sehingga perlu perbaikan pada penampang sungai. Perbaikan penampang dilakukan dengan penambahan tanggul sampai elevasi +4m pada ruas yang terpengaruh backwater.

River flooding causes several human and financial casualties. It is necessary to perform research studies and implement subsequent actions consistent with the nature of the river. In order to reduce flood damage, floodplain zoning maps and river cross-sectional boundaries are important to nonstructural measures in planning and optimizing utilization of the areas around the river. Due to the complex behavior of the rivers during floods, computer modeling is the most efficient tool with the least possible cost to study and simulate the behavior of the rivers. In this study, one-dimensional model Hydrologic Engineering Centers—River Analysis System and two-dimensional model CCHE2D were used to simulate the flood zoning in the Sungai Maka district in Kelantan state, Malaysia. The results of these two models in most sections approximately match. Most differences in the results were in the shape of the river.

There are different natural hazard, among these different natural hazards flood are most devastating and frequently occurring calamities taking human lives and causing economic damages. This report has been prepared to present hazard analysis mapping of flood of Punyamata River as a project work of 4th year student. The main focus of this project work was to determine the Elements at risk of the Punyamata River and to create flood hazard zone mapping of following years return period (5, 10, 20, 50, and 100). This project work explores the element at risk of the study area. The user’s requirement is extracted by experts view in qualitative way and system requirements are extracted by practice. Data requirement for flood hazard mapping are extracted from expert’s view and literatures. The hazard class map was performed by flood simulation process. Contours can be extracted from the system for Digital Elevation Model (DEM). The hazard map of various years return period and effected buffer zones are the main outputs from the system.

Nigeria has witnessed diverse flood events in the past years
and due to the high level of vulnerability and lack of coping capacity of
the people, with the fast occurrence of extreme events resulting from
climate change, many lives and properties are at risk of its impacts. This
paper reviews the recent past and present efforts in assessing the flood
impacts in Nigeria. We concentrate this study on the recent works
(methods and results) in assessing flood impacts in the country under
basic components of flood risk analysis: The hazards mapping and
modeling, exposure and vulnerability assessment, with the aim of
suggesting possible urgent needs and further development. Based on our
review, we conclude that, there is need to explore more effectively the
use of state of the art flood models, which integrates all hydrological
processes for more accurate prediction and mapping of flood and its
associated risks. Also, as one of the steps to plan for adaptation and
mitigation of future flood risk and climate change, there is a serious need
of detailed research in the development of regional or national flood
damage functions for pre-disaster flood damage estimation. The study
also suggests further study on the environmental and health impact of
flood in the country.
Keywords: Flood, Hazards Mapping, Vulnerability, Exposure, C

Flood is one of the striking water induced disaster that hits most of the part of the world. In Nepal
also it is one of the serious disasters which affect the human lives and huge amount of property. The increase of
population and squatter settlements of landless people living at the bank of the river has tremendous pressure in
encroachment of flood plain making them vulnerable to the flood damage. The study describes the technical
approach of probable flood vulnerability and flood hazard analysis. Bishnumati catchment was taken as area of
study. One dimension model of HEC-RAS with HEC-GeoRAS interface in co-ordination with ArcGIS was applied
for the analysis. Analysis shows that the flood area increases with flood intensity. Higher flood depth increases
and lower flood depth decreases with increase in intensity of flood. Inundation of huge area of urban land
indicates that in future human lives are more prone to flood disaster. Thus, the study may help in future
planning and management for future probable disaster.