Proceedings of ICHE2010, IIT Madras, Aug 2-5,2010 An Enhanced Two Dimensional Numerical Model for Simulating Floods due to Dam and Levee Break/Breaching 1 AN ENHANCED TWO DIMENSIONAL NUMERICAL MODEL FOR SIMULATING FLOODS DUE TO DAM AND LEVEE BREAK/BREACHING Altinakar M.S. 1 , M.Z. McGrath 2 , V.P. Ramalingam 3, H. Omari 4 , and E. Miglio 5 Abstract: Failure of dams and levees may lead to catastrophic floods that would cause loss-of- life and damage to urban and rural areas and may have serious consequences for the regional and/or national economy and security. Unfortunately, a large number of high-hazard and significant hazard dams in the USA do not yet have an emergency action plan (EAP), partly due to high-costs of studies using one-dimensional models. Two-dimensional models offer a cost- effective alternative but are not widely adopted by the engineering community. This paper describes a two-dimensional dam/levee breach flood model based on a first order shock capturing explicit scheme, which was enhanced with various advanced features to suit the needs of practicing engineers. Called CCHE2D-FLOOD, this numerical model allows definition of multiple water bodies and dams, each having its own breaching sequence. This feature can be used to simulate cascading dam failures. The user can define source and sink areas that can be used as inlets and outlets through which a discharge is introduced into or extracted from the regions of computational domain (without momentum input). Coupled source and sink areas can be defined to simulate controlled releases from appurtenances, such as bottom outlets (modeled as orifices) or spillways (modeled as weirs). CCHE2D-FLOOD offers a cut-cell boundary capability to simulate linear terrain features that cannot be captured by the resolution of the computational grid. The cut-cell boundary method is also used for providing coupled 1D-2D simulation capability. A graphical user interface (GUI) programmed as an extension to ArcGIS software by ESRI provides a user-friendly environment to set-up the model and to run the simulations. The results provided by the numerical model can be directly imported into a GIS- based post-processing module for evaluation of potential loss-of-life, urban and agricultural damage, and for preparing maps of danger criteria for humans, buildings, and vehicles, etc. Keywords: Dam break; 2D flood model; cut-cell boundary; cascading failures; controlled release. 1 Associate Director and Research Professor, National Center for Computational Hydroscience and Engineering, University of Mississippi, MS, USA, Email: altinakar@ncche.olemiss.edu 2 Graduate Student, National Center for Computational Hydroscience and Engineering, University of Mississippi, MS, USA, Email: mzmcgrat@ncche.olemiss.edu 3 Research Associate, National Center for Computational Hydroscience and Engineering, University of Mississippi, MS, USA, Email: virjay@ncche.olemiss.edu 4 Graduate Student, National Center for Computational Hydroscience and Engineering, University of Mississippi, MS, USA, Email: hhomari@ncche.olemiss.edu 5 Assistant Professor, Dept. of Mathematics "F. Brioschi", Politecnico di Milano, Italy, Email: edie.miglio@polimi.it; formerly visiting professor at the NCCHE, University of Mississippi, MS, USA Proceedings of Ninth International Conference on Hydro-Science and Engineering (ICHE 2010), IIT Madras, Chennai, India. 2 - 5 August 2010