Introduction of a stochastic approach in the development of a numerical model for tidal–fluvial interaction analysis and design

2006 ◽  
Vol 33 (8) ◽  
pp. 1027-1038
Author(s):  
F Yazdandoost ◽  
H Shamloo ◽  
A Adib
Keyword(s):  
Return Period ◽  
Interaction Analysis ◽  
Joint Probability ◽  
River System ◽  
Tidal River ◽  
Probability Method ◽  
Return Periods ◽  
Design Flood ◽  
Analysis And Design ◽  
Joint Probability Method

The interaction of tidal surges and fluvial flows in any river system results in a prevailing combined condition that requires accurate consideration in the reaches of the system not directly influenced by either phenomenon. The combined return period of the system should be deduced based on the combined effects of the two phenomena, which may usually be considered independent of one another. It is therefore imperative to consider both the return periods of the upstream flood condition and the downstream tidal surge condition to determine the combined return period for design flood analysis in tidal river systems. The task of obtaining a suitable and practical combination of the two phenomena encompasses preparation of an interactive scenario most closely and practically verified against the actual design event. In the present research, a combination coefficient has been introduced using the joint probability method. The combination coefficient is used to combine return periods of tidal surges and fluvial floods. A numerical and stochastic model has been developed for hydraulic routing in tidal rivers. The model is applied to the Karun River in Iran and the Severn River in the United Kingdom. The model can generally be utilized for river management and determination of safe bank height for tidal rivers.Key words: combination coefficient, tidal surges, river floods, joint probability method.

Applying POT methods to the Revised Joint Probability Method for determining extreme sea levels

2014 ◽  
Vol 91 ◽  
pp. 140-150 ◽  
Author(s):  
Franck Mazas ◽  
Xavier Kergadallan ◽  
Philippe Garat ◽  
Luc Hamm
Keyword(s):  
Joint Probability ◽  
Probability Method ◽  
Sea Levels ◽  
Extreme Sea Levels ◽  
Joint Probability Method

Évaluation des méthodes utilisées pour l'estimation de la crue maximale probable en régions nordiques

1999 ◽  
Vol 26 (3) ◽  
pp. 355-367 ◽  
Author(s):  
I Debs ◽  
D Sparks ◽  
J Rousselle ◽  
S Birikundavyi
Keyword(s):  
Return Period ◽  
Extreme Event ◽  
Snow Accumulation ◽  
Model Estimation ◽  
Hydrologic Response ◽  
Return Periods ◽  
Design Flood ◽  
Probable Maximum Precipitation ◽  
Maximum Precipitation ◽  
Probable Maximum Flood

Among all existing methods for estimating extreme floods, the probable maximum flood method is the safest, since it is a flood with a probability of excedance that is theoretically zero. In the early 1970s, this flood was calculated as the combination of the probable maximum precipitation (PMP) and the probable maximum snow accumulation (PMSA). In the 1990s, this combination has been considered to be highly improbable. Experts advise against combining two maximized events and, instead, recommend combining one maximized event with a relatively typical extreme event. This article presents a sensitivity analysis on the return period to be used for the typical extreme event to be combined with the maximized event to obtain a "more realistic" PMF. To achieve this, all the steps of a PMF study were reviewed and applied to the Sainte-Marguerite watershed, i.e., calibration and (or) validation of SSARR model, estimation of the PMP, the PMSA, and the temperature sequence. Different flood scenarios have been simulated including accumulated snowfall corresponding to return periods of 50, 100, and 500 years, followed by PMP and PMSA, followed by precipitation corresponding to return periods of 50, 100, and 500 years. It has been noticed that the use of a return period of 50, 100, or 500 years, to represent the unmaximized extreme event, has little effect on the hydrologic response of the basin. Based on the results of this work the use of a return period of 100 years is recommended.Key words: probable maximum flood, probable maximum precipitation, probable maximum snow accumulation, design flood, SSARR model.

Setting design inflows to hydrodynamic flood models using a dependence model

2012 ◽  
Vol 43 (5) ◽  
pp. 663-674 ◽  
Author(s):  
Duncan Faulkner ◽  
Caroline Keef ◽  
John Martin
Keyword(s):  
Return Period ◽  
Return Periods ◽  
Design Flood ◽  
Hydrodynamic Models ◽  
Site Specific ◽  
Flood Peaks ◽  
River Models ◽  
The Relationship ◽  
Flood Flow ◽  
Separate Regression

In setting design inflows to hydrodynamic models of flood flow along rivers, there can be a conflict between site-specific hydrological estimates of flow for a given return period and what the river model calculates as it routes flood hydrographs. This paper describes research carried out as part of the Flood Studies Update programme in Ireland, aimed at developing guidance on how to divide up river models and set the magnitude and timing of their inflows so that conditions in the model reach correspond to the expected design flood return period. A model for the joint distribution of flood peaks at pairs of catchments has been developed. The relationship between flood return periods is linked to physical differences between catchments. The model thus allows estimation of the statistical distribution of the flood return period expected at one site during a flood of specified return period elsewhere. A separate regression model predicts the relative timings of flood peaks on pairs of rivers. A summary of the resulting practitioner guidance is given, along with an overview of the testing of the method. The paper concludes with a discussion of the potential for application of the spatial dependence model to other problems in hydrology.

scholarly journals Risk Assessment of Coastal Flooding under Different Inundation Situations in Southwest of Taiwan (Tainan City)

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 880
Author(s):  
Moslem Imani ◽  
Chung-Yen Kuo ◽  
Pin-Chieh Chen ◽  
Kuo-Hsin Tseng ◽  
Huan-Chin Kao ◽  
...  
Keyword(s):  
Sea Level ◽  
Tide Gauge ◽  
Spring Tide ◽  
Joint Probability ◽  
High Water ◽  
Probability Method ◽  
Tide Gauge Records ◽  
Regional Sea Level ◽  
Tainan City ◽  
Joint Probability Method

The Pacific island countries are particularly vulnerable to the effects of global warming including more frequent and intense natural disasters. Seawater inundation, one of the most serious disasters, could damage human property and life. Regional sea level rise, highest astronomic tide, vertical land motions, and extreme sea level could result in episodic, recurrent, or permanent coastal inundation. Therefore, assessing potential flooding areas is a critical task for coastal management plans. In this study, a simulation of the static flooding situation in the southwest coast of Taiwan (Tainan city) at the end of this century was conducted by using a combination of the Taiwan Digital Elevation Model (DEM), regional sea level changes reconstructed by tide gauge and altimetry data, vertical land deformation derived from leveling and GPS data, and ocean tide models. In addition, the extreme sea level situation, which typically results from high water on a spring tide and a storm surge, was also evaluated by the joint probability method using tide gauge records. To analyze the possible static flood risk and avoid overestimation of inundation areas, a region-based image segmentation method was employed in the estimated future topographic data to generate the flood risk map. In addition, an extreme sea level situation, which typically results from high water on a spring tide and a storm surge, was also evaluated by the joint probability method using tide gauge records. Results showed that the range of inundation depth around the Tainan area is 0–8 m with a mean value of 4 m. In addition, most of the inundation areas are agricultural land use (60% of total inundation area of Tainan), and two important international wetlands, 88.5% of Zengwun Estuary Wetlands and 99.5% of Sihcao Wetlands (the important Black-faced Spoonbills Refuge) will disappear under the combined situation. The risk assessment of flooding areas is potentially useful for coastal ocean and land management to develop appropriate adaptation policies for preventing disasters resulting from global climate change.

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