What does life in, on and around the water look like in summer? To find out, we do in the series Splashing Drenthe a trip along the Drenthe water. Today we dive into the ditch. The Netherlands has 330,000 kilometers of ditches, and you can find everything in them.
Children also discover this during IVN Slootjesdagen. Armed with a scoop net and a bucket, they learn what lives and grows in a ditch in Oranjedorp. “I have found a water scorpion”, shouts one of the children. “With those little claws, he grabs his enemies and then he stabs them very quickly. He breathes with his buttocks.”
IVN organizes Slootjesdagen every year. “We try to involve children of primary school age from six to twelve more in nature,” says Tinus Knegt, volunteer at IVN Emmen-Coevorden. Everything the children have taken out of the ditch is put into an aquarium. With a search card, they can then find out what kind of animal they have found.
“It sometimes leads to surprising things,” says Knegt. “Children have found the little newt, but also the green frog, emperor dragonfly, the brown glazier and the ice skater.” According to Knegt, the point is that the children see a variety of beetles, spiders and other small animals. “That means there’s real aquatic life here.”
Ditch water quality
The children do this one afternoon, but ecologist Roy van Hezel is much more often in the ditch with a landing net. He closely monitors water quality for the Noorderzijlvest Water Board. “Ditches mainly have the function of supplying or draining water. In addition, they also have an ecological function, because of course everything lives in those ditches. Each ditch has its own ecosystem.”
According to Van Hezel, the quality of the ditch water is improving. “We can see this in the particles we measure, but also in all the aquatic life that occurs in a ditch. The more diverse the aquatic life is, the better the water quality.”
Together with farmers, the Water Board tries to improve the quality of ditch water in agricultural areas. “This can be done, for example, by sowing a flower-rich field edge along ditches. This ensures that fewer substances from agriculture end up in the ditches.” According to Van Hezel, it takes time. “But we can see that it is already much better than years ago.”
Landing and cleaning
Van Hezel can also see from the diversity of plants that things are going better than years ago. But a ditch that contains too many plants is not good either. Then a ditch will land. “This means that the ditch actually becomes shallower because more leaves and sand get stuck in it and more and more land plants start to grow. Then the water can no longer be supplied and drained. It is for the animals that live in the ditch . doesn’t live well either.”
According to Van Hezel, there is no question of drought in the ditches in the Noorderzijlvest area. “In our area, we are also lucky that we can supply water from the IJsselmeer. We have to use our water sparingly, because it is currently very dry in large parts of the Netherlands.”
If a ditch grows, it is partially cleaned. This means that part of the plants are removed. “If you remove everything, you reset the entire ditch. We prefer to leave some of the plants, so you maintain the ecosystem.”
Lock under magnifying glass
To show that one ditch is not the same, Van Hezel examines the aquatic life in two different ditches. Firstly, a ditch in an agricultural area near Vries, where a flower-rich mixture has been sown on the edge. The ditch itself is also rich in plants.
“For example, the ten-spined wedgebag swims here. This fish likes plant-rich water.” Van Hezel then steps into a ditch with a landing net in a residential area in Eelde. This ditch is fed by seepage, groundwater that rises under pressure from higher parts at lower parts. “A lot of different plants grow in this ditch, and that includes other water creatures.”
Are you curious about what kind of aquatic animals Van Hezel finds in both ditches? Then watch the video below. The text continues below the video.