FreshWater Watch archive
The Luxembourg WaterBlitz: what citizens measured in 2019 and 2021
This address: freshwaterwatch.thewaterhub.org once held the results map of the Luxembourg WaterBlitz, run with Earthwatch's FreshWater Watch. The map's data layer no longer loads; this page is The Water Hub's own summary of the published results and points to the data that survives.
The Luxembourg WaterBlitz was a citizen science event organised by the University of Luxembourg with Earthwatch, in which residents tested streams, rivers and ponds for nitrate and phosphate, first from 20 to 23 September 2019 and again in May 2021; across both, 35% of nitrate and 29% of phosphate readings exceeded the thresholds the European Environment Agency uses.
Who ran it
The 2019 event was organised by the University of Luxembourg in collaboration with Earthwatch, ran at the same time as WaterBlitz events in London, Dublin and Paris, and was funded by the Royal Bank of Canada (University of Luxembourg, 2019, archived). The second edition ran over the weekend of 7 to 10 May 2021 (University of Luxembourg, 2021). Volunteers recorded nitrate, phosphate and observations such as water colour and land use.
How many took part
The 2019 counts differ by source and by what was counted, so each is given as published. A peer-reviewed study of both events counts 132 samples in September 2019 and 296 data points in May 2021 (Stankiewicz and others, 2023).
| Source | People | Samples or records | Water bodies |
|---|---|---|---|
| Earthwatch, autumn 2019 report | 153 | 130 samples | not stated |
| University of Luxembourg, insights report | about 80 | 113 records | 56 (Alzette 19, Sûre 15) |
| Stankiewicz and others, 2023 | not stated | 132 samples | not stated |
What the results showed
In 2019 most of the water bodies measured were of medium nutrient status, and most of the high readings came from the more heavily populated areas, particularly around Luxembourg City; Luxembourg also had the least litter of the four cities, at 8% of records (WaterBlitz autumn 2019 report, archived). Across both events 35% of nitrate and 29% of phosphate values exceeded European Environment Agency thresholds, the share of nitrate readings above 5 mg/L fell from 48% in 2019 to 36% in 2021, and the study flags a hotspot on the Alzette between Walferdange and Schieren, near a leak at the Beggen treatment plant (Stankiewicz and others, 2023). In spring 2021 Luxembourg had the largest share of high phosphate readings of the regions taking part, about 28% (Earthwatch, spring 2021).
Where the data lives now
The old results map loaded its points from a server that no longer answers, so it cannot be shown here as it was. Every 2019 record is tabulated in the appendix of the university's insights report (WaterBlitz 19 Luxembourg insights, archived), and the whole FreshWater Watch dataset can be downloaded as CSV or Excel from freshwaterwatch.org.
Next: water testing services compared on The Water Hub.
Questions
When was the Luxembourg WaterBlitz?
From 20 to 23 September 2019, and again over 7 to 10 May 2021.
What did the Luxembourg WaterBlitz find?
Mostly medium nutrient levels, with high readings concentrated around Luxembourg City; 35% of nitrate and 29% of phosphate values exceeded European Environment Agency thresholds.
Can I get the Luxembourg WaterBlitz data?
Yes. The 2019 records are tabulated in the University of Luxembourg's insights report, and the FreshWater Watch dataset is downloadable from freshwaterwatch.org.
Sources
- University of Luxembourg: WaterBlitz 19 (archived), read 2026-10-21
- WaterBlitz autumn 2019 report (archived), read 2026-10-21
- WaterBlitz 19 Luxembourg insights report (archived), read 2026-10-21
- Stankiewicz and others, Citizen Science: Theory and Practice, 2023, read 2026-10-21
- Earthwatch: spring 2021 WaterBlitz results, read 2026-10-21
- University of Luxembourg: the 2021 study, read 2026-10-21