Hi! I’m Pim, 28 years old, and since August I’ve been active as a volunteer at PULSAQUA through Milieudefensie —an organization committed to environmental protection and raising awareness about Dutch environmental legislation. Within Milieudefensie, I’m following a traineeship on climate justice, a theme that closely aligns with PULSAQUA’s mission: promoting citizen science in the field of water research.
At PULSAQUA, I’m involved in the Drinkable Rivers Citizen Science Programme. My work focuses on researching, identifying, and recording macrofauna – the larger invertebrates such as insects, mollusks, and crustaceans. Thanks to my background in Applied Biology, I can use my knowledge to develop a clear and accessible manual for this research.
Recently, I took part in the measurement week, which gave me the opportunity to conduct research along the River Meuse in Venlo, the small city where I once studied. This place feels very familiar to me: a peaceful walking route along the water, surrounded by grazing cattle and blooming nature. This time, however, I wasn’t there for a stroll, but to observe the river scientifically and compare my findings with an earlier measurement I had done in a still watercourse of the Rotte.
With a backpack full of measuring equipment and the autumn sun warming my face, I settled down by the riverbank of the Meuse. Clear differences between the two waters soon became visible: the Meuse water was much clearer, had no smell, but also contained far less aquatic flora and fauna. While the water sample from the Rotte was teeming with red water fleas, the sample from the Meuse didn’t contain a single organism.
The chemical values also differed significantly. With a high pH of 8.6 in the Meuse — almost 1.0 higher than in the Rotte — and an electrical conductivity (EC) twice as high in the Rotte’s tributary as in the Meuse, the contrast was striking! This isn’t too surprising: the Meuse passes through several lime-rich regions before entering the Low Countries. Combined with the warm summer months and surrounding farmland, this results in calcium-rich waters, which is reflected in the pH levels. Although these minerals conduct electricity well, the EC is still much lower in the Meuse due to its fast-flowing water.
What I had learned on paper, I could now see in practice — and that’s what makes this work so valuable. The more people across the country take measurements, the better we can understand what’s happening beneath the water’s surface.
After about an hour, my work was done. With a head full of questions — and answers — I walked back home, satisfied and already curious about the next measurement.
I’ll definitely return to the Meuse. There, I truly feel like a fish in water.
Drinkable RiversTM CC 
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