The fish in the Beilervaart are having a hard time. Due to the hot weather and the drought, there is too little oxygen in the water. The Drents Overijsselse Delta water board has therefore taken measures. And that should not have happened a day later, because the fish were gasping for breath.
Last Monday, the Water Board received worried phone calls from local residents. The fish all stick their heads above the water and gasp for air. Ilse Winkel of the Water Board immediately takes a look and sees a whole circle with air bubbles. “I saw a whole school on the side, of course they immediately swam away because they scared me, but that is a sign that the oxygen is not good.” She measures the water and comes to the conclusion that there is indeed little oxygen for the fish.
The store intervenes immediately. “I had the Holthe pumping station shut down to find out where the oxygen shortage is. We call that a prop. If I had kept the pumping station running, that plug will continue the entire speed.”
She finds out what the weak spot is and calls a contractor. “They immediately aerated in the evening. They do this by pumping water from the Beilervaart and injecting it again, then oxygen is added. The next day we pumped water over from the adjacent Brunstinger Leek. Measurements showed that that water was more oxygenated.” The duckweed has also been removed, because duckweed that dies draws oxygen from the water.
After a few days the oxygen level has risen again and the pumping station turns again to spread the last small spots without oxygen. Shop was just in time. “Yeah, it shouldn’t have lasted much longer. Other years have seen a lot of dead fish floating, but that hasn’t happened now. So we were really right on time.” Due to the warm weather, the fish are not yet out of the danger zone. But can the Water Board pump water from a stream again with this drought? “Of course that’s not just possible,” explains Winkel.
“Of course we are dealing with drought, so we really take that into account. If the water level had been too low, this would not have been possible. But if we can, we will do it. Because we can’t just let all those fish die. And otherwise we can also switch to aerating only. That works a little less well, but as always better than doing nothing.” But for now, a new CPR attempt does not seem necessary. The fish are swimming on the bottom again and they seem to be doing well.