Is this year’s weed crisis worse than ever?
It looked, at first, that a cruise along the River Witham would be a gentle journey through rolling farmland interspersed with rustic villages. But while we waited in Lincoln for Liz’s surgery to heal, reports of impassable stretches of weed began to filter back.
We said goodbye to one narrowboat, only for it to return a few days later saying it couldn’t get through. The weed situation was so dire that it made the BBC local news! But if we were to make the Wash crossing this year, we needed to be on our way to the coastal exit point at Boston, so we took the advice with a pinch of salt and
ploughed on.
Was it a decision we were about to regret?
From Washingborough through to Woodhall Spa the river threw what it could at us, including a frisky, little water spout!
At each stop, Jamie reached into the weed hatch (stationed at the stern, just over the shaft and prop) to pull away the weed that had collected. It was bad, but not extreme enough to bring us to a halt; we never lost steerage or found ourselves floating helplessly in the river.
Why weed is threatening our waterways
Thick mats of vegetation clogging our rivers and canals block water flow, which increases the likelihood of flooding.
Apart from making life challenging for humans, weed overgrowth harms river life. Mats of floating weed block light from reaching underwater plants, causing them to die. And when the weed eventually decomposes, it sucks oxygen out of the water, killing fish and other water-dwelling life.
Invasive species like floating pennywort thrive in the UK, choking our more delicate native plants and ruining habitats that once were home to water voles and otters. Riverside species like Japanese knotweed and Giant hogweed cover banks in shade, forcing out smaller plants that can’t get enough light to flourish. In winter, when these giants die back, river banks are just bare soil, ripe for washing away during heavy rain.
Duckweed
A green carpet over the surface of rivers, canals and ponds. It doesn’t clog props, but it often hides floating obstructions which will get dragged into the weed hatch and stop props.
Floating Pennywort
This alien floating plant grows at a ferocious rate, perhaps as much as 20cm in a day. It is easily moved aside with a boat hook, but if your boat heads through one of its island mats, it will almost certainly entangle itself around your prop.
Blanket Weed
Not technically a “weed” because it is an algae, but its stringy tendrils form columns underwater and get scooped up by spinning props, where they will stop the boat dead.
We encountered all of these species, and probably others, on our passage to the CRT pontoon at Kirkstead Bridge, next to Woodhall Spa.
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