Protecting river banks from erosion

funkey_monkey

Has anyone here done any work to protect river banks from getting eroded?

Got a river flowing along our boundary and it is starting to undermine a tree on the bank at a bend in the river. I'll not have access to get a digger in to do work - unless the contractor can get in upstream.

I was thinking of planting willow along the affected section, but would that work without spilings as well?

There is flooding onto our land during heavy rain and I can't avoid that, but I would like to avoid further erosion as it may pull down our fencing.

Birdnuts

Makes sense - also significantly reduces silt and excess nutrient runoff from land

roosterman71

If that tree falls in you probably won't be allowed touch it without permission from the OPW, maybe the council and Inland Fisheries. Even then by asking they will most likely say no.

funkey_monkey

https://www.boards.ie/discussion/comment/121303266#Comment_121303266

I'm in NI. It'll probably get washed downstream in the floods blocking a bridge of causing other lands to be flooded.

I'm reading different accounts on the successfulness of willow, so not sure what to do here.

blue5000

Agreed with posts above. Willow will grow from cuttings so should be easy enough to do, just cut the bottom of the stick at an angle where a leaf stem was and it will take root. Maybe cut the tree that’s undermined so it doesn’t blow over. The stump will regrow.

Say my name

I doubt very much tree growth is going to stop a bank being undermined.

The only middling solution is rock armour.

White Clover

https://www.boards.ie/discussion/comment/121305147#Comment_121305147

Years ago lads around here used to drop in old cars where the bank was being eroded. There would be some knashing of teeth if it was done nowadays.

Base price

@funkey_monkey just a word of caution. Be very careful doing any works on rivers or streams. I would contact your local Inland Fisheries office and ask them to have a look a river. They may fund or partially fund the establishment of a rock defense as it will reduce silt been washed into the river which is problem for spawning grounds.

https://www.daera-ni.gov.uk/contacts/contact-your-local-fishery-office

Edit to add - streams.

timmyntc

You want to create a revetment using Willow cuts and general "brash"

Plant some timbers vertical by the bank, lay the brash between the timbers, then stick the Willow horizontally into the bank so it lies stuck on top/between the big wall of brash.

Willow will take root and grow out and the brash wall traps all nutrients and runoff. Over time the revetment accumulates soil and bank regrows partially.

davissgurban

Planting willow trees along the riverbank can help prevent erosion due to their strong root systems. Combining this with live fascines or spiling, which are bundles of live cuttings woven into structures, can enhance stability. Consulting local experts for specific advice tailored to your site is recommended.

roosterman71

Seen this on Twitter and thought of this thread

https://twitter.com/WelshDeeTrust/status/1719393890141188587

minerleague

https://www.boards.ie/discussion/comment/121309872#Comment_121309872

Those wooden barriers on bends like that are disaster water gets in around the back of them and gets worse than ever. Done near me - none worked long term, better to plant sedges, light bushy type trees

timmyntc

https://www.boards.ie/discussion/comment/121310001#Comment_121310001

Its not a solid wooden barrier though, the wood is just to keep the brash and deadwood in place to protect the bank and trap more silt and nutrients. Any water in behind it will drain out, but unlike in unprotected case, now force of river acting on bank is weakened & any runoff or erosion may be caught in brash.

These techniques are proven to work

minerleague

https://www.boards.ie/discussion/comment/121310210#Comment_121310210

Well in the ones I've seen the erosion continued and a line of timber posts left sitting with water in front and back of them and if anything the water between the posts and river bank speeded up and made it worse. It may well be that they weren't done right.

Funny though that rivers existed just fine without human intervention for thousands of years, maybe erosion and loops in rivers as a result are part of nature and ecosystems on their own. Saw a documentary on TV about river in Germany that had been straightened and "fixed" almost like a canal but they lost a lot of biodiversity and caused flooding downriver as water moved too quickly, now spending millions to try and get it back to a more natural state

funkey_monkey

We'll not do anything without further investigation.

I've posted about this elsewhere and the replies align with here where nothing really stands out as a suitable solution. Willow can be undermined (apparently) as it increases river speed which deepens the bed and undermines the trees. From looking at spiling photos I can see how they could increase speed.

Dredging the inside of the meander would probably help, but doing it on your own bat is not worth the risk and I doubt anyone in the dept would want to even consider listening to a request. I got grant funding to fence it off to keep the stock out of the river, so it would be awkward if they would not allow me to prevent the fencing from landing in the river. However, with the times in it I'm not sure how a request would be met.

I'll keep an eye on it over this winter and see if/how it progresses and take it from there - will need to see if/what I am allowed to do first. Was just wondering if anyone here had a fix that worked for them.

rs8

Is it a opw drain/river? They might rock armour it!! My neighbour had a similar problem... the type of soil was very sandy and the drain (not a river) was undercutting it and washing it away .. no tress could help (be it the ones that were there/or planting new ones) he cut the few trees that were left , got a local contractor in to Deeping the centre a fraction and got a couple of loads if rock from local quarry to rock amour it with a digger. Worked well .. on low flow it works down the centre and high flow the banks are protected. It was about 15 years ago when things were quieter and a lad got away with a few things. I wouldnt recommend doing anything yourself without the go ahead of local authorities or opw especially where there's fish etc involved.

funkey_monkey

No, just a regular river. It is just one part. Annoying thing is that if it pulls the tree down it will pull down recently installed grant aided fences and maybe bring a recently planted small woodland into risk.

Will leave it until spring and see what we can do. Can't really see why i am not able to protect the bank. Will try to find some info first.

148multi

https://www.boards.ie/discussion/comment/121313147#Comment_121313147

Read somewhere that every mile per hour water increases in speed it's destructive force increases sixteen time

Birdnuts

https://www.boards.ie/discussion/comment/121365386#Comment_121365386

Highlights alot of the problems with the OPW's approach to flood protection