The weather conditions this summer make it all the more obvious. Besides periods of drought, we in the Netherlands also continue to face the effects of heavy rainfall. The most intense example of heavy rainfall this summer is the rainfall with flooding in Limburg last July.
The extreme amount of precipitation that fell in Limburg (according to KNMI, on 13 and 14 July, in some locations fell more than twice the normal amount of precipitation for the whole month of July[1]) ended up on already saturated ground in a very short time. Rivers and streams could not process the extreme precipitation fast enough and burst their banks. In a short time, the environment changed extremely: flooded floodplains, flooded plots of land and even flooded city centres and residential areas in Valkenburg and Meerssen, for example.
These uncertain situations lead to acute questions: Which areas exactly are flooded? How high is the water and how fast is it receding? Which houses, plots and infrastructure works are accessible, damaged or under water?
Using up-to-date satellite images, before, during and after extreme weather events, such practical questions can be answered for a large area within hours. With this information, emergency services can determine the most efficient route to urgent situations and crisis managers can determine where the need is greatest. Even afterwards, this is still useful information for insurers and designers of new solutions, for example. Another advantage of using satellite data is that the acquisition costs are a lot cheaper compared to other remote sensing sources, such as aerial photos or drone images.
The supply of current satellite data is large. There are more and more commercial satellite constellations in space offering near-real time satellite data. Radar constellations such as those from Capella Space can take very detailed recordings even at night and in all weather conditions. As an example, the attached image shows the situation around the Juliana Canal on 16 July (the peak of the flooding) and 17 July. The black spots show the flooded areas, buildings in white. By 17 July, the flooded areas have largely dried up again.
[1] https://www.knmi.nl/over-het-knmi/nieuws/onderzoek-naar-hevige-overstromingen-in-limburg-ardennen-en-eifel
