The expected rainfall in the coming days may have serious consequences for the fish that live in ditches or streams. “Multiple causes can ensure that the fish may have a shortage of oxygen, in the worst case they can die,” says spokesperson Martin Hilferink of Waterschap Vechstromen.
One of those reasons is the lack of rain and the persistent heat of recent weeks. This decreases the oxygen level in the surface water, making it more difficult for fish to survive. In addition, the expected rainfall ensures that the accumulated waste in the sewage system ends up in that surface water. Hilferink: “Due to the heavy rain, the flow in the sewage system can become blocked, so that this waste ends up in the surface water. As a result, the water quality decreases even further, which can have fatal consequences for the fish.”
Tackling this problem is a difficult task for the water board. “In principle, there is not much we can do about it. It is mainly a problem that nature solves itself. We can take a preventive approach and ensure that oxygen-rich water is pumped in so that the fish can survive. “
Another option is to transfer fish to other streams or ditches. “We see that a lot in Twente, but we often don’t opt for it here. In Drenthe we often opt for pumping extra water in streams,” says Hilferink.
The water board advises against helping the fish yourself. “If you see fish gasping for breath, or if you see them lying lifeless in the water, please contact the water board. It is dangerous for yourself and for the fish to take them out of the water independently, because you can still affect the water quality. further deteriorate. In addition, the fish may be infected with botulism, which in turn can be harmful to humans. We take every report seriously and look at what action is necessary on a case-by-case basis to solve the problem.”
Hilferink expects the oxygen problem to persist for several days. “We see this happen more often during periods of heavy rainfall. It is something nature has to solve itself, so the most important thing is to report it so that we can get started.”