The work deals with the assessment of the stream Chribska Kamenice current state in the village Vsemily urban area. The aim of the project is the assessment of capacity and the current state of the stream-bed. Based on an assessment measure there has been designed the improvement suggestion of the current state and flood protection increasing in close neighbourhood.

När klimatet i Sverige blir varmare ökar både förekomsten och omfattningen av intensiva skyfall. Dessa kan leda till stora konsekvenser lokalt för drabbade samhällen. Omfattande översvämningar, skadade fastigheter, erosionsskador och hindrad framkomlighet är några av de potentiella följderna. Ett första steg för att öka beredskapen för skyfall är att göra en skyfallskartering där ett nederbördstillfälle med skyfallskaraktär läggs in i en hydraulisk modell över ett område. Modellen visar sedan områden som riskerar att drabbas av översvämningar samt vilken väg som ytavrinningen tar under förloppet. I detta arbete har en sådan modell gjorts över Sala stad. Skyfallsmodellen skapades i programmet HEC-RAS och för att simulera infiltrationen användes metoden SCS curve number. SCS curve number metoden uppskattar infiltration baserat på markanvändning och jordart. Typregnet valdes till 100 års återkomsttid och modellerades som ett CDS-regn med varaktighet sex timmar och klimatfaktor 1,3. Ett avdrag på nederbördsmängden gjordes även för dagvattennätets kapacitet. Resultatet blev att flertalet områden i Sala kan drabbas av potentiellt stora vattendjup. De största problemområdena identifierades till bebyggelsen mellan Ringgatan och Östra Tulegatan söder om centrala Sala samt området kring Pråmån uppströms Jakob Mats kvarn. Då infiltrationsmetoden SCS curve number är baserad på empiriska data gjordes en känslighetsanalys på infiltrationsparametrarna. Det som undersöktes var påverkan på total andel infiltrerad nederbörd och översvämningarnas utbredning. Tre olika scenarion baserat på osäkerheten i curve number-talet användes samt ett scenario utan infiltration i modellen. Skillnaden i total översvämmad yta med ett djup större än 0,1 m mellan scenariot med högst infiltration och scenariot med lägst infiltration var i modellen totalt 9,1 procentenheter. I det scenario där ingen infiltration modellerades drabbades flertalet nya fastigheter och infrastruktur av översvämning vilket visar på infiltrationens betydelse för riskbedömningen vid en skyfallskartering. Totalt infiltrerade 30 % av nederbörden i modellen vid scenariot med lägst infiltration, 49 % av nederbörden vid scenariot med direkta litteraturvärden för curve number- talet och 66 % av nederbörden i scenariot med högst infiltration. Eftersom infiltrationen mellan scenarierna til hög grad berodde på hur jordarterna klassades i modellen är det dock svårt att dra en generell slutsats om vilket infiltrationsscenario som är bäst lämpat att använda vid skyfall. / As the climate becomes warmer in Sweden the frequency and extent of cloudbursts are expected to rise. When these rain events occurs in populated areas the consequences can be severe for the local community with extensive flooding leading to for example damaged properties, erosion and obstructions of traffic. One step to increase the awareness of these risks is to do a cloudbust mapping were a rain with cloudburst extent is modelled hydraulically. Areas that are at risk of flooding during the rain event and flow paths for the surface runoff can be assessed from the model. In this thesis such a model was created for the town of Sala. The cloudbust model was made using the software HEC-RAS and to simulate infiltration the method SCS curve number was implemented. The rain event was modeled as a Chicago design storm with a return period of 100 years, total duration of six hours and a climate factor of 1,3. The results were that several areas in Sala were at risk of flooding. Two main areas with risk of major flooding extents were located to just south of central Sala between Ringgatan and Östra Tulegatan and adjacent to Pråmån upstream of Jakob Mats kvarn. Because of uncertainties in the SCS curve number model and due to the fact that it is based on empirical data a sensitivity analysis was also done on the infiltration parameters. For the sensitivity analysis four different scenarios were used. One scenario had no modeled infiltration and the three other scenarios were based of error estimations of the curve number parameter called antecedent runoff conditions. The difference in flooding extent with a depth greater than 0,1 m in the model between the scenario with high infiltration and the scenario with low infiltration was 9,1 percentage points. Several new properties and infrastructure were affected in the scenario when no infiltration was used. In total 30% of the precipitation infiltrated in the model in the scenario with low infiltration, 49% infiltrated in the scenario with literature values for the curve number value, and 66% of the precipitation infiltrated in the scenario with high infiltration. Since the infiltration is highly dependent on the classification of the soils in the model no overall conclusion could be drawn on which infiltration scenario that is best suited for a cloudburst model in general when the SCS curve number method is used to model infiltration.

Begreppet översvämningar har länge varit ett väl diskuterat ämne inom den akademiska världen och har även nu på senare år uppmärksammats alltmer i nyheter samt av allmänheten i sin helhet. Översvämningar är inte längre ett naturfenomen som kan anses inträffa vid sällsynta tillfällen. Den ökade globala uppvärmningen och det förändrade klimatet spås ge en ökning av extrema nederbördstillfällen. Så sent som 17–18 augusti 2021 drabbades stora delar av Gävle av översvämningar till följd av ett extremt skyfall. Kunskap om och förmågan att kunna hantera dessa extremfenomen är väsentligt för framtidens samhälle. Med detta i åtanke har denna studie undersökt hur översvämningsutbredningen och utbredningen på tillhörande osäkerhetszoner skiljer sig beroende på framställningssätt. Med hjälp av HEC-RAS har både endimensionell (1D) och tvådimensionell (2D) hydrauliska modeller använts för att simulera den översvämning som drabbade Gävle. Studien har utförts som en fallstudie över Västra Kungsbäckens vattendrag. Global Navigation Satellite Systems (GNSS) har använts för att skaffa noggrannare batymetrisk data. Genom en korrigerad höjdmodell och fotografier från översvämningen från den 18 augusti 2021 kunde modellerna kalibreras. Därefter utfördes flödesmodellering och vidare framställdes översvämningskartor och översvämningskartor med osäkerhetszoner. Resultatet visar att den utbredning översvämningen fick beroende på modell var mycket lika. Viss skillnad föreligger i geometrin men den procentuella utbredningen (2,3 %, 5 837 m2) är minimal. När det kommer till osäkerhetszonsutbredningen framgår den totala ytan väldigt lika mellan modellerna men däremot förekommer en större skillnad i geometrin för de två områdena; säkert att översvämmas och osäkert att översvämmas mellan modellerna. Utifrån studiens förutsättningar har ett tillförlitligt resultat tagits fram där fältstudien med mätningen har förbättrat tillförlitligheten på höjddata och kalibreringen av modellen har gjorts utifrån väl beprövade metoder i litteraturen. Ytterligare validering har gjorts mot en tidigare studies resultat och slutsatsen som kan dras är att modellerna är tillförlitliga. Likt all framställning av kartor förekommer det även osäkerheter i denna studie och fler studier över andra områden krävs för att fastställa hur en endimensionell modell skiljer sig mot en tvådimensionell ur ett utbredningsperspektiv. För osäkerhetsutbredningen krävs det fler studier med 2D-data för att kunna bekräfta de antaganden som gjorts. / The concept of floods has long been a well discussed topic in the academic world and has even now in recent years received increasing attention in the news and also by the general public. Floods are no longer a natural phenomenon that can be considered to occur on rare occasions. The increased global warming and the changing climate are predicted to result in an increase in extreme cloudbursts. As recently as 17–18 August 2021, large parts of Gävle were affected by floods as a result of an extreme downpour. Knowledge of and the ability to deal with these extreme phenomena is essential for cities of the future. With this in mind, this study has examined how the prevalence of flooding and the prevalence of associated zones of uncertainty differ depending on the method of production for flood maps. With the help of HEC-RAS, both one-dimensional (1D) and two-dimensional (2D) hydraulic models were used to simulate the flood that affected Gävle. The study has been carried out as a case study of the western part of the stream Kungsbäcken. Global Navigation Satellite Systems (GNSS) has been used to get more accurate bathymetric data. Through a corrected elevation model and photographs from the flood of 18 August 2021, the models could be calibrated. Subsequently, flow modeling was performed and further flood maps and flood maps with uncertainty zones were produced. The results show that the extent of the flood depending on the model was very similar. There are some differences in the geometry, but percentage wise, the extent difference (2,3 %, 5 837 m2) is minimal. When it comes to the uncertainty zones produced, the total areal extent is very similar between the models, but there is a greater difference in the geometry for the two areas; certain to be flooded areas and uncertain to be flooded areas between the models. Based on the study’s conditions, a result has been achieved where the field study with the measurements has improved the reliability of elevation data and the calibration of the model has been based on well-proven methods in the literature. Further validation has been done against the result of a previous study and it can be concluded that the models are reliable. Like all map production, there are also uncertainties in this study and more studies on other areas are required to determine how a one-dimensional model differs from a two-dimensional one from a distribution perspective. For the prevalence of uncertainty, more studies with 2D data are required to be able to confirm the assumptions made.

Flood risk assessment in urban areas necessitates the utilization of advanced modeling strategies to accurately depict inundation patterns and potential impacts on communities and infrastructure. This study investigates the impacts of varying 2D modeling strategies on flood risk assessment in the context of the Garonne River flood risk prevention plan. The research focuses on building 2D hydraulic models for the Garonne and Ariège rivers using Telemac 2D, supplemented by models for their tributaries on HEC-RAS. Following calibration, the 1875 reference flood event is simulated, sensitivity analyses were conducted on downstream boundary conditions, Strickler coefficient for the floodplain, and discharge parameters. The results reveal significant impacts of these parameters on the final hazard maps, underscoring the importance of thoughtful consideration in model calibration and parameter selection. It also questions the strategy to base the assessment on an extreme historical flood event with little data to back up the accuracy of the results, or favoring a less extreme event that will lead more accurate results, but with maybe less security.  The study highlights the critical role of high precision topography, particularly in flat and urban areas, where traditional discharge data may be lacking, and precipitation-based methods may prove less effective. The choice of modeling software also emerges as a key factor influencing the accuracy of flood hazard assessments, with variations in parameters and computation methods yielding differing outcomes.  Overall, this research underscores the complex interplay between modeling strategies, parameter selection, and topographic characteristics in urban flood risk assessment. It emphasizes the need for a nuanced approach in choosing flood events for modeling, balancing the availability of data with the accuracy and reliability of results. / Riskbedömning av översvämningar i stadsområden kräver användning av avancerade modelleringsstrategier för att korrekt beskriva översvämningsmönster och potentiella effekter på samhällen och infrastruktur. I denna studie undersöks effekterna av olika 2D- modelleringsstrategier på bedömningen av översvämningsrisker i samband med planen för förebyggande av översvämningsrisker i Garonnefloden. Forskningen fokuserar på att bygga hydrauliska 2D-modeller för floderna Garonne och Ariège med Telemac 2D, kompletterat med modeller för deras bifloder i HEC-RAS.  Efter kalibrering simuleras 1875 års referensflöde, känslighetsanalyser utförs på nedströms gränsvillkor, Strickler-koefficienten för översvämningsslätten och flödesparametrar. Resultaten visar att dessa parametrar har en betydande inverkan på de slutliga riskkartorna, vilket understryker vikten av noggranna överväganden vid modellkalibrering och val av parametrar.  Studien belyser den kritiska roll som högupplöst topografi spelar, särskilt i platta och urbana områden, där traditionella flödesdata kan saknas och nederbördsbaserade metoder kan vara mindre effektiva. Valet av modelleringsprogramvara framstår också som en nyckelfaktor som påverkar noggrannheten i bedömningen av översvämningsrisker, med variationer i parametrar och beräkningsmetoder som ger olika resultat.  Sammantaget understryker denna forskning det komplexa samspelet mellan modelleringsstrategier, val av parametrar och topografiska egenskaper vid riskbedömning av översvämningar i städer.  Den betonar behovet av ett nyanserat tillvägagångssätt när man väljer översvämningshändelser för modellering, och balanserar tillgången på data med resultatens noggrannhet och tillförlitlighet.

The primary objective of this thesis is to develop hydrologic and hydraulic models for the Soap Creek Watershed, IA for the evaluation of alternative flood mitigation strategies and the analysis of the differences between hydrologic and hydraulic routing methods. In 2008, the state of Iowa suffered a disastrous flood that caused extensive damage to homes, agricultural lands, commercial property, and public infrastructures. To reduce the flood damage across Iowa, the U.S. Department of Housing and Urban Development (HUD) awarded funds to the Iowa Flood Center and IIHR-Hydroscience &Engineering at the University of Iowa to conduct the Iowa Watersheds Project. The Soap Creek Watershed was selected as one of the study areas because this region has suffered frequent severe floods over the past century and because local landowners have organized to construct over 130 flood detention ponds within it since 1985. As part of the Iowa Watersheds Project, we developed a hydrologic model using the U.S. Army Corps of Engineers’ (USACE) Hydrologic Center’s hydrologic Modeling System (HEC-HMS). We used the hydrologic model to evaluate the effectiveness of the existing flood mitigation structures with respect to discharge and to identify the high runoff potential areas. We also investigated the potential impact of two additional flood mitigation practices within the Soap Creek Watershed by utilizing the hydrologic model, which includes changing the land use and improving the soil quality. The HEC-HMS model simulated 24-hour design storms with different return periods, including 10, 25, 50, and 100 year. The results from modeling four design storms revealed that all three practices can reduce the peak discharge at different levels. The existing detention ponds were shown to reduce the peak discharge by 28% to 40% depending on the choice of observed locations and design storms. However, changing the land use can reduce the peak discharge by an average of only 1.0 %, whereas improving the soil quality can result in an average of 15 % reduction. Additionally, we designed a hydraulic model using the United States Army Corps of Engineers’ (USACE) Hydrologic Engineering Center’s River Analysis System (HEC- RAS) to perform a comparative evaluation of hydrologic and hydraulic routing methods. The hydrologic routing method employed in this study is the Muskingum Routing method. We compare the historical and design storms between HEC-HMS, HEC-RAS, and observed stage hydrographs and take the hydrograph timing, shape, and magnitude into account. Our results indicate that the hydraulic routing method simulates the hydrograph shape more effectively in this case.

Many river bridges fail or are seriously damaged due to excessive local scouring around piers and abutments. To protect a bridge from scour-induced failure, it should be designed properly against excessive scouring and its scour criticality should be checked regularly throughout the service life to take prompt action. The Federal Highway Administration of United States (FHWA) developed a program, HYRISK, as a basis for evaluation of existing scour failure risk of a bridge. It provides implementation of a risk-based model, which is used to calculate the annual risk of scour failure of a bridge or series of bridges in monetary values. A case study is carried out for a bridge crossing Fol Creek in Black Sea Region (close to Vakfikebir), for the illustration of this software. Besides, hydraulic analysis and scour depth computations of the bridge are carried out via HEC-RAS program. Also, a study is carried out to recommend scour countermeasures that can be applied to the aforementioned bridge.

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references (p.100-101).

Esse trabalho identificou, testou e aprimorou modelos de propagação de vazão simplificados a fim de verificar as vantagens e desvantagens dos modelos. As soluções apresentadas por esses modelos foram testadas com um modelo hidrodinâmico completo, considerado nesse trabalho como resultados ideias. Os modelos hidrodinâmicos simplificados testados foram: Um modelo não linear de Onda Cinemática, o modelo Muskingum-Cunge linear, duas versões do modelo Muskingum-Cunge não linar, o modelo Muskingum-Cunge modificado por Todini e o modelo IPHS1. O modelo hidrodinâmico completo utilizado nesse trabalho foi o modelo HEC-RAS. Desenvolveu-se ainda uma metodologia para representar o efeito da planície de inundação. Essa metodologia foi implementada nos modelos hidrodinâmicos simplificados. Para avaliar o comportamento dos diferentes modelos de propagação disponíveis foram criados testes numéricos em que foram aplicados os diferentes modelos, com variação de características dos hidrogramas sintético de entrada, das características do leito do rio e da planície de inundação, e dos critérios de discretização temporal e espacial. A avaliação dos resultados foi feita através dos erros de conservação de volume, de vazão de pico e de tempo de ocorrência da vazão de pico. Além disso, também foram considerados, em alguns testes, os critérios de aplicabilidade de Ponce para onda cinemática e difusão além da formulação do Δx ideal proposto por Fread. Os resultados mostram que o modelo Muskingum-Cunge Todini, modificado para representar o efeito da planície de inundação, é muito promissor. Esse modelo apresentou resultados que se aproximaram muito dos resultados obtidos pelo HEC-RAS, enquanto os outros modelos hidrodinâmicos simplificados apresentaram resultados piores. Com relação aos critérios de aplicabilidade, recomenda-se o uso de um Δx três vezes menor do que o valor sugerido por Fread. Além disso, pode-se concluir que os modelos simplificados podem ser utilizados fora dos limites de aplicabilidade sugeridos por Ponce. / This work has identified, tested and improved simplified flood routing models to verify the advantages and disadvantages presented. The solutions provided by these models were tested by using a full hydrodynamic model considered in this work as an ideal result. The simplified hydrodynamic models used were: A variable parameter kinematics wave model, the Muskingum-Cunge flood routing model, the variable parameter Muskingum-Cunge flood routing model (three and four points scheme) the Muskingum-Cunge modified by Todini (MCT) and the model IPHS1. The full hydrodynamic model used was HEC-RAS. It was also proposed a procedure to represent the effect of the floodplain rivers. To evaluate the behavior of different flood routing models numerical tests were created and were applied to then. The characteristics of synthetic inflow hydrographs, the characteristics of riverbed and floodplain, and the criteria for temporal and spatial discretization were perturbed. The evaluation of the results was made through the errors of conservation of volume, peak flow and time of occurrence of peak flow. Moreover, it was also considered, in some tests, applicability criteria recommended by some authors for different models, such as models of kinematic flood wave and diffusive flood wave. The results show that the Muskingum Cunge Todini, modified to represent the effect of the floodplain flow is very promising. Finally, it is also shown that this model closely approaches the full Saint Venant equation solution (HEC-RAS). The others models were worse than HEC-RAS and MCT. About applicability criteria, it recommends the use of the Δx three times smaller than the value suggested by Fread. Moreover, the simplified hydrodynamic models can be used outside limits of applicability suggested by Ponce about kinematic and diffusive wave.

Esse trabalho identificou, testou e aprimorou modelos de propagação de vazão simplificados a fim de verificar as vantagens e desvantagens dos modelos. As soluções apresentadas por esses modelos foram testadas com um modelo hidrodinâmico completo, considerado nesse trabalho como resultados ideias. Os modelos hidrodinâmicos simplificados testados foram: Um modelo não linear de Onda Cinemática, o modelo Muskingum-Cunge linear, duas versões do modelo Muskingum-Cunge não linar, o modelo Muskingum-Cunge modificado por Todini e o modelo IPHS1. O modelo hidrodinâmico completo utilizado nesse trabalho foi o modelo HEC-RAS. Desenvolveu-se ainda uma metodologia para representar o efeito da planície de inundação. Essa metodologia foi implementada nos modelos hidrodinâmicos simplificados. Para avaliar o comportamento dos diferentes modelos de propagação disponíveis foram criados testes numéricos em que foram aplicados os diferentes modelos, com variação de características dos hidrogramas sintético de entrada, das características do leito do rio e da planície de inundação, e dos critérios de discretização temporal e espacial. A avaliação dos resultados foi feita através dos erros de conservação de volume, de vazão de pico e de tempo de ocorrência da vazão de pico. Além disso, também foram considerados, em alguns testes, os critérios de aplicabilidade de Ponce para onda cinemática e difusão além da formulação do Δx ideal proposto por Fread. Os resultados mostram que o modelo Muskingum-Cunge Todini, modificado para representar o efeito da planície de inundação, é muito promissor. Esse modelo apresentou resultados que se aproximaram muito dos resultados obtidos pelo HEC-RAS, enquanto os outros modelos hidrodinâmicos simplificados apresentaram resultados piores. Com relação aos critérios de aplicabilidade, recomenda-se o uso de um Δx três vezes menor do que o valor sugerido por Fread. Além disso, pode-se concluir que os modelos simplificados podem ser utilizados fora dos limites de aplicabilidade sugeridos por Ponce. / This work has identified, tested and improved simplified flood routing models to verify the advantages and disadvantages presented. The solutions provided by these models were tested by using a full hydrodynamic model considered in this work as an ideal result. The simplified hydrodynamic models used were: A variable parameter kinematics wave model, the Muskingum-Cunge flood routing model, the variable parameter Muskingum-Cunge flood routing model (three and four points scheme) the Muskingum-Cunge modified by Todini (MCT) and the model IPHS1. The full hydrodynamic model used was HEC-RAS. It was also proposed a procedure to represent the effect of the floodplain rivers. To evaluate the behavior of different flood routing models numerical tests were created and were applied to then. The characteristics of synthetic inflow hydrographs, the characteristics of riverbed and floodplain, and the criteria for temporal and spatial discretization were perturbed. The evaluation of the results was made through the errors of conservation of volume, peak flow and time of occurrence of peak flow. Moreover, it was also considered, in some tests, applicability criteria recommended by some authors for different models, such as models of kinematic flood wave and diffusive flood wave. The results show that the Muskingum Cunge Todini, modified to represent the effect of the floodplain flow is very promising. Finally, it is also shown that this model closely approaches the full Saint Venant equation solution (HEC-RAS). The others models were worse than HEC-RAS and MCT. About applicability criteria, it recommends the use of the Δx three times smaller than the value suggested by Fread. Moreover, the simplified hydrodynamic models can be used outside limits of applicability suggested by Ponce about kinematic and diffusive wave.

Esse trabalho identificou, testou e aprimorou modelos de propagação de vazão simplificados a fim de verificar as vantagens e desvantagens dos modelos. As soluções apresentadas por esses modelos foram testadas com um modelo hidrodinâmico completo, considerado nesse trabalho como resultados ideias. Os modelos hidrodinâmicos simplificados testados foram: Um modelo não linear de Onda Cinemática, o modelo Muskingum-Cunge linear, duas versões do modelo Muskingum-Cunge não linar, o modelo Muskingum-Cunge modificado por Todini e o modelo IPHS1. O modelo hidrodinâmico completo utilizado nesse trabalho foi o modelo HEC-RAS. Desenvolveu-se ainda uma metodologia para representar o efeito da planície de inundação. Essa metodologia foi implementada nos modelos hidrodinâmicos simplificados. Para avaliar o comportamento dos diferentes modelos de propagação disponíveis foram criados testes numéricos em que foram aplicados os diferentes modelos, com variação de características dos hidrogramas sintético de entrada, das características do leito do rio e da planície de inundação, e dos critérios de discretização temporal e espacial. A avaliação dos resultados foi feita através dos erros de conservação de volume, de vazão de pico e de tempo de ocorrência da vazão de pico. Além disso, também foram considerados, em alguns testes, os critérios de aplicabilidade de Ponce para onda cinemática e difusão além da formulação do Δx ideal proposto por Fread. Os resultados mostram que o modelo Muskingum-Cunge Todini, modificado para representar o efeito da planície de inundação, é muito promissor. Esse modelo apresentou resultados que se aproximaram muito dos resultados obtidos pelo HEC-RAS, enquanto os outros modelos hidrodinâmicos simplificados apresentaram resultados piores. Com relação aos critérios de aplicabilidade, recomenda-se o uso de um Δx três vezes menor do que o valor sugerido por Fread. Além disso, pode-se concluir que os modelos simplificados podem ser utilizados fora dos limites de aplicabilidade sugeridos por Ponce. / This work has identified, tested and improved simplified flood routing models to verify the advantages and disadvantages presented. The solutions provided by these models were tested by using a full hydrodynamic model considered in this work as an ideal result. The simplified hydrodynamic models used were: A variable parameter kinematics wave model, the Muskingum-Cunge flood routing model, the variable parameter Muskingum-Cunge flood routing model (three and four points scheme) the Muskingum-Cunge modified by Todini (MCT) and the model IPHS1. The full hydrodynamic model used was HEC-RAS. It was also proposed a procedure to represent the effect of the floodplain rivers. To evaluate the behavior of different flood routing models numerical tests were created and were applied to then. The characteristics of synthetic inflow hydrographs, the characteristics of riverbed and floodplain, and the criteria for temporal and spatial discretization were perturbed. The evaluation of the results was made through the errors of conservation of volume, peak flow and time of occurrence of peak flow. Moreover, it was also considered, in some tests, applicability criteria recommended by some authors for different models, such as models of kinematic flood wave and diffusive flood wave. The results show that the Muskingum Cunge Todini, modified to represent the effect of the floodplain flow is very promising. Finally, it is also shown that this model closely approaches the full Saint Venant equation solution (HEC-RAS). The others models were worse than HEC-RAS and MCT. About applicability criteria, it recommends the use of the Δx three times smaller than the value suggested by Fread. Moreover, the simplified hydrodynamic models can be used outside limits of applicability suggested by Ponce about kinematic and diffusive wave.