Watching the news over the Christmas holidays I spotted some footage of an area that I recognised – the footbridge by Asda in Radcliffe. The clip showed the river rising and destroying the bridge whilst the gas main exploded sending a plume of flame up into the sky….dramatic stuff…
The bridge in question has been used by me for several years as part of my ‘weed walk’ when taking clients to show them invasive species actually in the ‘flesh’ so to speak rather than just on a slide or power-point presentation. When standing on the (now non-existent) bridge – one used to be able to see the whole spectrum of invasive species – Japanese Knotweed, Giant Hogweed, Himalayan balsam, ragwort, Rosebay willow herb ….and the odd self-seeded sycamore trying to get established.
The number of invasive species and the bridge collapsing are not simply …a coincidence – what we have here is a number of factors all collecting in a perfect storm of connected problems…
Himalayan balsam grows on the flood plain of the river – growing to the preclusion of our native species.
Japanese Knotweed grows unchecked along the bulk of the higher reaches of the banks.
Giant hogweed in-fills any area not covered by Japanese knotweed
Acer pseudoplatanus then crops up wherever it can …
So – with this perfect mix of invasive non-native species we get a series of issues during times of flood.
The floodwaters tend to rise over winter
The invasive plants on the river bank reduce capacity for flow
The Himalayan balsam within the flood area dies back over winter
The balsam does not have a root system capable of holding the soil together
The river bank collapses and Japanese knotweed and giant hogweed all fall into the watercourse
The overflows created by the Environment Agency are all protected by steel cages
The steel cages get blocked with debris and the overflows don’t work
The river continues to rise
The bridge collapses
…and repeat – year after year
Then on top of the above scenario we have fragments of viable Japanese knotweed floating off downstream ready to start growing wherever they land. Seeds of Himalayan balsam and seeds from Giant Hogweed all heading off downstream in their thousands ready to take over wherever they eventually settle…
This is a WAR people!
Be aware ….floods don’t just damage buildings and property…they damage our ecosystems and our environment. It’s easy to see damage to carpets and to soft furnishings ….it’s far more difficult to prioritise dealing with new weed growth in areas severely hit by flooding. Treating this new growth in its early stages of development will be far more economical than trying to sort these issues once they are established.
Following treatment in these areas we need to be then making sure that NATIVE species are planted and that these NATIVE plants are protected and managed to ensure successful establishment.
Managed watercourses and managed catchments are what we need to ensure a stable flood free future.
So Floody hell, this is a floody big problem – let’s get our floody heads together and let’s take some floody action!