Delft Measures Rain

With Delft Measures Rain, we aim to understand the variability of rainfall in cities. Together with citizens, we increased this resolution 100-fold by using low-cost manual rain gauges and weather stations and measuring during the storm season. For already 2 consecutive years we have been able to collect high resolution and reliable rainfall data.

Stage of the project




Starting Up





Why was this project started?

Due to the difficult circumstances that measuring rainfall in cities brings, the measurement resolution is low, creating insecurities about rainfall distribution and its effect on inundation levels.
During Delft Measures Rain, we try to increase the number of rain gauges, so that we can do a daily measurement for every km2 of Delft. We aim to do at least 1 measurement per km2 of the city for the duration of 3 months. To do this, we use manual rain gauges and sensors that will be connected to the WOW-KNMI network of local weather stations.

But furthermore, we believe that doing this together with the citizens of in this case Delft not only helps to find answers but also to increase awareness and educate the citizens about how to take rainfall measurements, how much rain actually falls in their city, and what happens when there is a storm event with high precipitation amounts.

The results of the project so far

Between July and September of 2020, we received 1991 measurements from 95 participants. These data were subsequently analysed by TU Delft student Illias Timori, guided by principal investigator Marie-Claire ten Veldhuis. The results are promising! Not only did we receive a lot of data, but most of the data is as reliable as the official KNMI (Royal Dutch Meteorological Institute) data. Because the KNMI has a lot less rain gauges per square kilometer, Delft Measures Rain provides a higher resolution of rain measurements within Delft. That is exactly what we were looking for! You can find an overview of the most important results in the infographic:

In 2021, 105 citizens of Delft have gathered 5128 rain measurements over a three month period (1st August-31st October)! The data until September 17th have been analyzed by two TU Delft students, Karen Chen and Rafaël van Beek. The results look very promising and you can find a summary of them in this infographic:
Additionally, we organized a webinar on November 24th, during which Karen and Rafaël have presented their results. You can find their presentations here (in Dutch):

All the data points can be found on our data map (map 4):

What are specific, distinctive, strong elements in this project?

- participation of citizens
- stakeholder inclusion (municipality, cso, several university departments, meteorological organisation)
- successful data collection used by more partners for different goals
- educational benefits for both citizens as students who use it as case-study for their theses
- mostly online engagement and recruiting of participants was quite successful

Which specific lessons, do's and don'ts would you like to share? What would be suggestions for others when preparing or implementing the project in their own city?

Of course, there are several, and perhaps too many to mention here. We will leave it therefore to one:
As you can see, we have already implemented the project for two consecutive years, and the first year gave us much input to improve the quality of the results in the second year. The biggest lesson we learned was to emphasize and better explain why to measure around the same time in the morning. This was important for analyzing the data. Therefore, make sure that the expectations the first time are according to this, and use it as a pilot to improve upon.

Have others adopted, or shown interest in adopting, your idea in their own area?

We have had several conversations with other interested parties about implementing the project perhaps on a broader scale and in neighboring cities.

Can you tell us how valuable this project was for you?

You can rank your answers on a scale from 1 (lowest) to 5 (highest).

Indicates required field
1. How valuable was this information for you?
Not so much
A lot
2. Will you use this information in your own practice?
No I won't
Yes for sure
3. Could this project be shared to - and implemented in - your own city?
No I won't
Yes I think so

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