Physical vulnerability of mains to climate change

Climate change can lead to a higher probability of failure in drinking water mains. Analysis of failure data in USTORE, covering the last five years, shows that the number of pipe fractures increases for AC and small steel pipes under high temperatures. Among the possible reasons for this are the increase in water use when temperatures rise, which can lead to higher internal loading (depending on the pressure regime) in the pipes; and the greater dryness and soil settling occurring in hot periods, which can lead to higher external loading. Based on the scenarios of the KNMI (Royal Netherlands Meteorological Institute), one can see that dry periods are becoming more common and temperatures rising, so that an increase in mains failures can be expected. How a pipe responds depends on the material it’s made of.

The objective of the research is to asssess the physical vulnerability of different types of water mains to climate change.

Verandering in storingen van leidingen bij verandering in temperaturen (van links naar rechts toenemende temperatuurklassen).

Changes in failure frequencies in mains with changes in temperature (from left to right: rising temperature classes)

Four sub-studies

The project involves four sub-studies:

  1. Climate-resilience of PVC, PE and cast iron

Besides a literature search of the climate-resilience of these types of mains, we also conduct practical research into slow-crack growth, the main failure mechanism in PVC mains.

  1. Effect of peak loadings

This involves research into the connection between demand peaks and the weather: When and where do these demand peaks occur? We also study the connection between pressure and demand: Where in the distribution network does a higher demand peak result in higher pressure or pressure variations? We also research the relation between demand and failures.

  1. Regional differences in failures

This includes more statistical analysis of data on regional failures and data from regional weather stations, for example.

  1. Search for climate extremes

We collect and analyse failure data and local weather data for climate regions that are comparable to the Netherlands, and for climate regions where the current climate is comparable to that expected in the Netherlands in 2050.

Predicting mains network vulnerability based on scenarios

The research concludes with a report in a scientific journal, in which we make predictions, for the different 2050 climate scenarios, regarding the vulnerability of the mains network. Taking into account the expected composition of the network at that time, the better statistical connection between the weather and failures, we can make a prediction of the expected number of failures in the mains.