Can utilities save overflows if they manage their drainage system better?

Is there really much overflow to be saved if the utility manages its drainage system better?
Or is governance just a buzzword reserved for the few?


This is what Envidan’s Nadia Lund set out to find out in her industrial postdoc, which she is doing in collaboration with six Danish utilities, DTU Sustain and Envidan.

To answer this question, Nadia has spent the last year developing a tool that quickly and automatically calculates how much overflow a given utility can save by managing their drainage system.

The tool builds on results from the utilities’ MIKE URBAN models. In the current setup, four years of radar data are run through the model to understand how the system behaves today, where overflows occur and where the available capacity is. The tool then automatically analyzes the results and indicates in the form of plots or visual GIS maps how much the utility could achieve in overflow reduction by better managing different components of the drainage system.

It turned out that it was actually worthwhile for most of the utilities to manage one or more locations better – and some utilities could even save a lot of overflow.

The participation of the six utilities Novafos, Odsherred Forsyning, Silkeborg Forsyning, Skanderborg Forsyning, Mariagerfjord Vand and Ikast-Brande Spildevand has been crucial for the development of a usable tool.

Workshop with six utilities

In March 2022, Nadia and the six utilities held a workshop with the six utilities to mark the completion of the potential tool and to move forward with the work on how to exploit the identified potential by using the rule-based governance tool. The headline for the workshop was: How can we make use of the identified potential using rule-based governance?

Developing the governance strategy itself is one thing, but there are also many aspects that determine whether a utility should implement governance. Therefore, the workshop included interesting discussions on:

  • What makes it easy or difficult to implement governance in a given location?
    There may be physical circumstances that make it operationally difficult to implement governance in a given location. As an example, this could be if a new throttle is to be placed in a pipe located under a pedestrian street or a busy road.
  • What other barriers to governance exist?
    Even when the potential tool allows utilities to quickly and easily identify whether there is physical potential in their catchment area, there are still many other things that can prevent a utility from choosing governance. For example, there may be a lack of cooperation between the utility’s planning and operations departments, a general lack of knowledge about management in the utilities, that management is perceived as risky and difficult to operate, and that many Danish utilities are very busy.
  • What is the good process for implementing governance?
    It is individual from supply to supply, but there are different steps that the supply usually has to go through. This includes, among other things, drawing up an actual management strategy, clarifying the risks and consequences of this and initiating possible measurement programs – and then, of course, the governance must eventually be implemented in the utility’s SCADA system. It is also important that the utility includes their operations in the project early in the process and benefits from their knowledge and experience of the system.

Next steps in Nadia’s industrial postdoc

Which rule-based management strategies can be implemented in the different river basins to exploit the potential?

Nadia will now start looking at how we can specifically control pumps, throttles etc. in the six utilities to reduce overflows. She will also start looking at co-management, i.e. how to best manage the overall system consisting of both the sewerage system and the treatment plant.

Do you want to learn more about the tool and its potential or Nadia’s industrial postdoc in general?

Contact me
for more information

Nadia Schou Vorndran Kirstein


+45 61 42 14 14