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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Flood risk management and adaptation : Automating hec-ras input data and execution for improved hydraulic analysis: the bolivian amazonia 2...
Automating hec-ras input data and execution for improved hydraulic analysis: the bolivian amazonia 2014 flood
Author : VLADIMIR MOYA QUIROGA(1), SHUICHI KURE(1), KEIKO UDO(1) & AKIRA MANO(1)
ABSTRACT
The Bolivian Amazonia is an extent floodplain region that continuously suffers flooding from the most important Bolivian
rivers. One example is the Mamore River, the longest and most important Bolivian river and one of the main tributaries of
the Amazon river. Despite the importance of the river and the frequency of the floods, there are almost no studies about its
flood risk. Development of a hydraulic numerical model able to simulate flood scenarios is an important step in order to
perform flood risk analysis. Selection of a proper Manning roughness coefficient and boundary condition are vital steps at
implementing a hydraulic model. However, such values cannot be measured and are prone to a wide range of uncertainty.
Although there are some empirical suggestions, they are just suggestions and the proper values need to be calibrated. The
calibration process is a time consuming one as it requires several simulations considering different values. Besides, any
proposed action should be considered by modifying the model and updating the simulation. Thus, it is important to develop
tools for easing the process of updating changes to a hydraulic model. This paper presents a tool developed for automating
the boundary conditions and roughness input of HEC-RAS, one of the most popular hydraulic models, along with an
automatization of its execution. The tool eased the task of performing a sensitivity analysis of boundary condition and
roughness coefficients. Several simulations were easily performed considering several probable boundary conditions and
roughness coefficients according to different criteria and suggested values. The different roughness coefficients showed
that the water level may change up to 3.47 m depending on the coefficient to be used. Uncertainties from Manning roughness
and boundary condition may generate differences that may propagate up to 600 km upstream. This tool proved to be a
valuable tool for improving hydraulic studies considering different uncertainties. The model was then used to simulate the
2014 flood event at the Bolivian Amazonia. A Manning value of 0.035 provides good results for steady flow, and a Manning
value of 0.0314 the model successfully simulates the flood event under unsteady flow condition showing the moment when
the water begins to overflow and the duration of the flood. However, the model still can be improved by considering a variable
Manning with values little higher than 0.035 for the low flows and values little lower than 0.029 for the high flows.
File Size : 960,426 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Flood risk management and adaptation
Date Published : 20/08/2015
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