3-code coupling in flood simulation

The flood 2002 at the Elbe River showed that besides the apparent damages by surface waters, considerable damage was caused by groundwater and waters from the sewer system. Fast rising groundwater levels due to infiltration of overland flow or water from the sewer system can damage basements and can be a serious thread to the static of houses. The objective of the project 3ZM-GRIMEX is the development of a software system for the coupled simulation of three components: surface water, groundwater, and sewer water. The coupled system will be used in flood risk management. The implementation of the software system is based on MpCCI. Exchanged quantities are water heights and water fluxes between the components. The paper describes the coupled software system and the involved application codes with emphasis on the requirements for MpCCI. Challenges include that all application codes are interacting with each other, the codes are 1-, 2- as well as 3-dimensional, and the time-scales in the codes are very different. Furthermore, the paper outlines the use of MpCCI, including the development of suitable code adaptors with a coupling driver, the time step negotiation, the coupling algorithm, and a dummy code used for tests and as substitute. Finally, numerical results for a generic test model will be given. Simulations of the flood 2002 at Dresden are planned for 2007.