In Germany’s inland waterways, Canadian waterweed and narrow-leaved waterweed are the most widespread invasive species. For skippers, the dense carpet of these plants becomes an insurmountable obstacle in many places. There is currently no sign of a sustainable improvement.
Low water levels accelerate uncontrolled growth
The fact that the aquatic plant known as Elodea proliferates during the summer months is not, at first glance, a new problem for sailing clubs. Similar conditions already caused massive problems back in 2018. This year, however, the situation is compounded by the extreme and prolonged heatwave. A very warm early summer is coinciding with sharply falling water levels, which in some places along the Rhine are reaching near-record lows.
The sun reaches right down to the riverbed, which massively accelerates the growth of waterweed. This mainly affects bays and harbours with slow-moving water. However, the weed is now taking root even in the river branches where there is still a noticeable current – a current which had previously prevented its growth in recent years.
Loss of manoeuvrability for sailing boats and motorboats
The consequences for day-to-day operations on the Rhine are serious. Harbour Master Klaus Dosch from the Mainspitze Sailing Club explains that it is currently no longer possible for them to cast off: “As soon as you cast off, the propeller or the rudder blade gets caught in the seaweed.” If the seaweed isn’t cleared regularly in the harbour, no boat can get out of its berth safely.
“You’re unable to manoeuvre. It really is a disaster,” the harbour master continued. For safety reasons, the yachts are therefore currently moored securely to the jetties. Normal training sessions and regattas have been cancelled in many places. The phenomenon is affecting all water sports. Whilst propellers are becoming blocked on the Rhine, a junior rowing championship at Lake Baldeney in Essen even had to be rescheduled due to heavy weed growth.
Waterweed: No solution in sight
In many places, mowing boats are now being used to combat the rapid spread of waterweed. However, this is not a sustainable solution. The plant spreads rapidly and regrows quickly. Moreover, even the tiniest piece that is cut off and left on the bed of lakes and rivers immediately takes root and grows again. So, unless all the cuttings are carefully removed and brought ashore after mowing, the plant can return even more vigorously than before.
Furthermore, a severe shortage of equipment is causing frustration, as the few specialist boats are fully booked this season, at least on the Rhine. A professional mowing operation costs around 10,000 euros, which is hardly affordable for smaller clubs. The club at the tip of the Main is therefore left with no option but to carry out the labour-intensive task of manually clearing narrow navigation channels using rakes. A natural end to this nuisance is not expected until the end of August, when the plants die off as part of their normal seasonal cycle.
Further news:
David Ingelfinger
Volontär
