SEMA Asset Management Strategies for Sewer Systems

Project title

Sewer deterioration model for asset management strategy

Project initiator

Kompetenzzentrum Wasser Berlin gGmbH

Project volume

487,811 €

Project start



30 months


Asset management is an increasing concern for wastewater utilities and municipalities. In the last 30 years, most cities have invested in sewer system expansion and treatment plant upgrade but a relatively small component has been allocated to the improvement of sewer system condition. In order to avoid the general deterioration of sewer system and the risk reversing public health, environment and increasing costs, tools are needed to develop long term cost-effective strategies.

The definition of sustainable rehabilitation and inspection strategies is limited by the lack of information about sewer system condition. Therefore, sewer deterioration models have been developed (i) to simulate the condition of non-inspected sewers and (ii) forecast the evolution of the system according to his current and past condition. Simulation results can be used by sewer operators to support the definition of cost-effective inspection and rehabilitation programs. Since the confidence in deterioration models depends highly on their ability to predict accurately future sewer condition, research is needed to assess their performance and define their relevant specifications.

The project SEMA aims

  • to investigate the suitability of sewer deterioration model to predict sewer condition state and
  • to identify the relevant specifications of sewer deterioration models and input data in respect to a successful utilisation.

Sewer deterioration models will be applied in the cities of Braunschweig and Montbéliard, in close collaboration with the engineering company 3S Consult GmbH (3SC). Model precision and sensitivity will be tested using several configurations of input data.

Considering the project results, a second project (SEMA 2) will be developed to assess the pertinence of sewer deterioration models to support the definition of inspection and rehabilitation strategies.



  • Caradot N., Sonnenberg H., Hartmann A., Kropp I., Ringe A., Denhez S., Timm M., Rouault P. (2015), The potential of deterioration modelling to support sewer asset management. 6th IWA Leading Edge Strategic Asset Management Conference, 17-19 November 2015, Yokohama, Japan
  • Caradot N., Sonnenberg H., Hartmann A., Kropp I., Ringe A., Denhez S., Timm M., Rouault P. (2015), The influence of data availability on the performance of sewer deterioration modelling. 10th International Urban Drainage Modelling Conference, September 20-23, Mont-Saint-Anne, Quebec, Canada
  • Caradot N., Sonnenberg H., Rouault P., Hartmann A., Kästner A., Kropp I., Ringe A., Timm M., Mesek C. (2014), Wie zuverlässig sind Kanalalterungsmodelle? Inspektions- und Sanierungstage - DWA, 12-13 November 2014, Dortmund, Deutschland
  • Caradot N., Sonnenberg H., Kropp I., Schmidt T., Ringe A., Denhez S., Timm M., Hartmann A., Rouault P. (2014), What is the reliability of sewer deterioration models? IWA World Water Congress, 21-26 September 2014, Lisbon, Portugal
  • Caradot N., Sonnenberg H., Kropp I., Schmidt T., Ringe A., Denhez S., Hartmann A., Rouault P. (2013), Sewer deterioration modeling for asset management strategies – state-of-the-art and perspectives. 5th IWA Leading Edge Strategic Asset Management Conference, 9-12 September 2013, Sydney, Australia


Nicolas Caradot (KWB)


Financial support: