Bank stabilisation

[Tom D]

Any planting recommendations for stabilisng a steep bank down to a fast flowing stream, currently a lot of ash but much of it was severely undermined in recent floods, we will be heavily pollarding many of the ash trees so light levels should be good initially. I was thinking white willow but quite open to other suggestions.

[Stephen Blair]

i hear japanese knot weed grows quite well mate.

[Charlieh]

it wont work,

 

simples

 

 

you need to look at installing flow deflectors and upstream woody debris in the channel to help reduce flow against the toe of the bank, brash bundles along the base of the bank will also allow the bank to slump over the top of the material thus forming a less steep gradient, any replanting wants to be quite a way from the bank top

[woodplans]

We have used this method to stop undercutting on river banks. Willow Bundles weighed down with rocks and anchored to the river bed and banks, cover with soil and wait for regrowth of willow. The willow ends trap sediment by slowing down the current and help to rebuild the bank.http://arbtalk.co.uk/forum/attachment.php?attachmentid=28898&stc=1&d=1265096094http://arbtalk.co.uk/forum/attachment.php?attachmentid=28897&stc=1&d=1265096094

[csservices]

I have seen willow used by knocking in willow stakes into the stream bed and then weaving withies inbetween in the same style as woven hurdles, or another alternative would be to use large stone ie old walling stone banked up on a slant to protect the bank at the stream edge and then plant above

[Charlieh]

I have seen willow used by knocking in willow stakes into the stream bed and then weaving withies inbetween in the same style as woven hurdles,

this is willow spiling, there is a section in the btcv handbook on rivers and wetlands which you can view online, its a great technique but not generally practical on very spatey rivers, it can be used with reprofiling to help keep the spoil behind the spiling and also provides a good fish and invert cover in the channel

 

or another alternative would be to use large stone ie old walling stone banked up on a slant to protect the bank at the stream edge and then plant above

This would require Environment agency consent for a structure in the floodplain, and should in many cases a last resort but does have its place, although EA in many places dont look favourably on it, as it generally just shifts the erosion issues downstream

[Tom D]

I should have said, this is a fast flowing stream which in spate is quite powerful, I am really looking to try and prevent any further landslips into the river by locking the bank together a bit more securely. I dont think any tree would withstand the full force of the spate.

[Tony Croft aka hamadryad]

[Robert_S]

would you not need to divert the flow to stop it undercutting the banking,you could always throw in some gabion baskets then plant the banking up not very eco friendly but may slow the erosion down enough for the trees to get a grip.

[Tony Croft aka hamadryad]

In fisheries management we learnt its better to just try and slow down the current going into the cut to allow silt and then plants to get their own way in, a few stakes and a bit of dead hedging in the water should suffice. work with nature instead of against it, depends on the scenario though if the current is hitting on a bend its a hard thing to reduce and gabions may be the only resort.

 

Of course rivers naturaly alter themselves, but we humans dont like allowing nature to run its course!