Dam-Break Modeling

 

 

The Dam-Break Modeling Research Group focuses on the numerical modeling of floods, with an emphasis on rapidly varying catastrophic floods (such as flash floods, floods due to dam-break or levee breach, etc.) and the related bed level changes. Special numerical techniques are developed for these types of floods, which often involve discontinuities (hydraulic jump, traveling positive wave) and mixed flow regimes over complex terrain topography.

Malpasset Dam-Break Flood
Click to play a video clip

 

Land-Slide generated waves in Lake Sarez
Click to play a video clip

The Great Mississippi River Flood of 1927 Frontispiece - beginning of crevasse breaching levee at Mounds Landing, MS (from: http://www.photolib.noaa.gov/)

 

Research Goals

The Dam-Break Modeling Research Group has the mission:

1. Develop and refine state-of-the-art numerical methodologies and models with shock capturing capability for predicting flood inundation due to catastrophic floods (dam-break, levee-breach, flash flood, etc.), the accompanying sediment transport process, and the impact of such floods on environment and ecological system.

2. Use these state-of-the-art numerical models to assist government agencies and private institutions in conducting flood risk assessment studies, planning and designing flood control project, and establishing early warning system and emergency action plans.

 

Research Activities

The current research interests are focused on the following areas:

1. Refinement and improvement of raster grid based CCHE2D-FLOOD model and addition of new capabilities:

• development of faster algorithms to reduce computation time

• inclusion of various boundary conditions,

• better interfacing with GIS software and tools

2. Development of unstructured grid based 2D flood model

The present model is based on a structured rectangular mesh. It can in fact directly use geo-referenced DEM files as mesh. While this has certain advantages, depending on the shape and orientation of the computational domain, it may also result in a large number of unused cells in the computational mesh, thereby increasing storage requirements and computational time. The research is underway for developing a new version of CCHE2D-FLOOD based on unstructured grid. This research also includes development of a user friendly GUI (Graphical User Interface).

3. Modeling of dam breach and levee breach processes

At the present the CCHE2D-FLOOD assumes an instantaneous total destruction of the dam of the levee. The research is being carried out to include algorithms for gradual and partial destruction scenarios based on available semi-empiric methods, and computation of the erosion process based on sediment transport calculations.

4. Modeling of dam-break flow on movable bed

Dam-break or levee-breach type fast floods are accompanied by intensive sediment transport and rapid changes in the bed elevation. Modeling of non equilibrium sediment transport and the related bed level variation accompanying such rapidly varying unsteady flows is a highly challenging research area. The time scale of bed-level changes approaches hydrodynamic time scales. The Saint-Venant-Exner equations must therefore be solved with strong coupling of liquid and solid phases.

 

Projects

Listed are past and current Dam-Break Modeling Research Group projects:

1. Numerical prediction of land-slide generated waves in Lake Sarez, Tajikistan

Lake Sarez was formed in February 1911 when a landslide triggered by a major earthquake created a 600m-high natural dam and blocked the flow of Murgab River. The stability of this natural dam, and the safety of some 5 million people living at the downstream of the dam along the Bartang, Panj, and Amu-Darya rivers have long been a serious concern. NCCHE, in collaboration with Stucky Ltd, Lausanne, Switzerland, has carried out numerical simulations to investigate the consequences of various landslide scenarios.

2. Development and Refinement of Multi-Dimensional Numerical Tools for Simulating Dam Break and Riverine Floods 

U.S. Army Research Office: Grant No. W911NF-04-1-0048

In the initial phase the research activities are focused on testing and validation of the available CCHE2D-FLOOD model using various available data. The research will be carried out for upgrading computing speed using new algorithms, and improving visualization capabilities. The second phase is devoted to supporting user applications of the CCHE dam break model. New model capabilities are added (such as estimation of unknown bed elevation of a reservoir, and the implementation of a “reservoir release” option for the simulation of the effects of a large controlled release from a dam as opposed to dam failure). The final phase of the research project will be devoted to further refinement of the model and development of additional capabilities such as simulation of a partial dam break flood event. Further developments will include better pre- and post-processing, new visualization capabilities, interfacing with third party software such as GIS programs.

 

Researchers

Research Leader
Post Doctoral Research Associate
Dr. Xinya Ying

Research Professor
Dr. Mustafa Altinakar

Research Assistant 
Mr. Onur Akay

 

Software

1D or 2D numerical simulation of flood propagation over complex topography, flood delineation, and flood mapping.

The CCHE FLOOD, developed by Dam-Break Modeling Research Group, is a finite volume model based on the solution of the full dynamic shallow water equations in conservative form. CCHE-FLOOD exists in both one-dimensional and two-dimensional versions. The model is particularly adapted for simulating real flood propagation over complex topography. It can be used to determine arrival/receding times of flood waves, to delineate the inundated area and to plot flow-depth contours as a function of time, to carry out operational flood-risk analysis and mapping, etc.

The 2D version of CCHE-FLOOD can be efficiently used for studying flood propagation due to dam-break, and embankment or levee breaching. Click here to obtain more information on CCHE-FLOOD. 

 

Publications

1. Ying X., Sam S.Y. Wang, and A.A.Khan, “Numerical Simulation of Flood Inundation Due to Dam and Levee Breach”, Proceeding of ASCE World Water & Environmental Resources Congress 2003 (CDROM), Philadelphia, June 23-26, 2003.

2. Ying X., A. A. Khan, and Sam S. Y. Wang, “An Upwind Method for One-Dimensional Dam Break Flows,” Proceeding of XXX Congress of International Hydraulic Research Association, Greece, August 2003, pp. 245-252.

3. Ying X. and Sam S.Y. Wang, “Two-dimensional numerical simulations of Malpasset dam-break wave propagation,” Proceeding of 6th International Conference on Hydroscience and Engineering (CD ROM), Brisbane, Australia, May 30 - June 3, 2004 

4. Ying X. and Sam S.Y. Wang, “Parallel computing in flood simulations,” Proceeding of 6th International Conference on Hydroscience and Engineering (CD ROM), Brisbane, Australia, May 30 - June 3, 2004

5. Ying X., Mustafa S. Altinakar and Patrice Droz, “Numerical prediction of landslide generated waves in Lake Sarez using CCHE2D-FLOOD”, Proceeding of 6th International Conference on Hydroscience and Engineering (CD ROM), Brisbane, Australia, May 30 - June 3, 2004

6. Ying X., A. A. Khan, and Sam S. Y. Wang, "Upwind conservative scheme for the Saint Venant equations", Journal of Hydraulic Engineering, (in press)

 

Links

(FEMA) Federal Emergency Management Agency