Urban flash floods

Calculation of flooding through urban flash floods. The hydraulic simulation of the surface runoff in case of a canalization overload is done by means of a 2-dimensional calculation approach. The spatial extent, the chronological progression and the water depth of flooding may be analyzed. Precautionary measures may be deduced from the analysis and verified for their effectiveness.

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Functionalities of the software

"Urban flash floods" is the itwh software package for the calculation of flash floods caused by heavy rainfall. The package contains the 2-dimensional surface runoff model HYSTEM-EXTRAN 2D and FOG for the administration of sewer system models as well as FOG 2D for the creation of the terrain model in ArcGIS.

Exceptionally heavy rainfall events lead to the overload of sewer systems with the implication that flash floods with negative impacts on urban infrastructure or even danger to life can occur. With the itwh software package "urban flash floods" the hazards of heavy rainfall can be analyzed in detail. Through the linkage of the sewer system model HYSTEM-EXTRAN with the 2-dimensional surface runoff model HYSTEM-EXTRAN 2D a detailed simulation of the runoff processes in the sewer system and on the surface is made. 

Thereby

  • spatial extent
  • chronological progression and
  • water depthdie

may be analyzed and visualized.

In the calculation the sewer system model HYSTEM-EXTRAN and the 2D model HYSTEM-EXTRAN 2D of the surface are linked bidirectionally through manholes and street inlets. The water leagage from the sewer system through overflow, as a result of the overload of the sewer system, as well as the reentry, if capacities are available, are visualized in detail. The results of the calculations may be visualized and classified to assess the entent of potential damage through flash floods. This in turn forms the basis for a risk assessment acording to DWA-M 119. 

Field of application

  • Hazard analysis by means of simulation of flash floods with random rainfall events (natural of model rainfall and radar rainfall data) according to DMA-M 119
  • Verification of possibilities of a damage-free discharge aboveground 
  • Simulation of planning options
  • Basis for investigation of flash flood risk

Demo version

Download Portal

Please note: HYSTEM-EXTRAN, FOG and ArcGIS are required.
An ArcGIS-Testversion is available here.

Support and Updates

For support, licenses and further information, please do not hesitate to contact us.

System requirements

For the GIS-workplace:

  • Operating systems: Windows 10, Windows 8, Windows 7 (respectively 64-Bit)
  • At least ESRI ArcGIS 10.1 Desktop Basic
    An ArcGIS test version is available here
  • For netzworking: MS Windows server (others on request), catalogue with full access privileges for all users
  • The hardware requirements comply with the operating system in use

For the simulation computer:

  • Operating systems: Windows 10, Windows 8, Windows 7 (respectively 64-Bit)
  • HYSTEM-EXTRAN 7.8
  • .NET-Framework 4.0 (will be installed if necessary) as well as IE 7 or more recent
  • For networking: MS Windows Server (others on request), catalogue with full access privileges for all users
  • The hardware requirements comply with the operating system in use