Best timber for reinforcing the bank of a large pond

[Bunzena]

We have been asked to reinforce the bank of a large pond.  The bank on one side is about 2-3 feet above the water and is eroding away.  Each winter larger chunks of soil and turf drop in.  The length of bank that needs to be worked on is quite short [maybe 30-40 feet long].

 

Having looked at a variety of options - and the one that seems to be most popular is to insert a number of vertical posts into the pond; then cross-connect with thick  boards and then back fill.  The question is - what timber to use?  I don't have huge budget - and whatever I use needs to be fairly readily available.

 

I've had a bad experience over the past 4-5 years with Oak and it rotting off.  Sleepers, posts - the lot.  I know it's normally very durable but I'm struggling to spot the duff-stuff before it's been installed.

 

I've considered using UC4 [slightly worried about the preservative leaching out] - but the quality can be pretty variable.  And 'in a pond' is a pretty challenging environment.

 

Also considered Sweet Chestnut and Larch.  Considered using recycled/reclaimed 'exotics' [such as Greenheart] - but the cost is pretty high. 

 

Anyone give me a heads-up on what they'd use?  Thanks.

[Stubby]

If you had something to drive them in with then steel interlocking shuttering . Like on sea defenses  harbor walls etc . Bit over kill perhaps but fit and forget .

Edited October 30, 2018 by Stubby

[AHPP]

Plastic? You can screw, drill etc easily.

[Yournamehere]

I've been doing this on fishing ponds for a long time now. Chestnut posts with scaffold boards behind will last a surprisingly long time. And new boards can easily be slid in behind in/ in front as required. It's cheap and gets you started.

What we are doing now though is making a 'lifetime' investment and using pretend sleepers from jewson/coombers/... held in place with scaffold tubes which are grindered off to give a neat finish. Or these with very sturdy chestnut post might do for you.

A long stretch of bank will benefit from some anchors tied into the bank to stop it falling forward.

Buy a post rammer - worth their weight in gold - don't use a sledge. Don't ram the soil in behind - it expands and pushes your boarding outwards - just place it in and let it settle.

Plant yellow flags in front to make it look good. (Flags alone will protect a bank from erosion). Canary grass is well rooty and used behind /on top will tie the soil together.

Discourage willow growth at the water's edge.

[Yournamehere]

Oh yeah. Put landscaping fabric behind the woodwork. The water will find its way into any little hole it can and will soon wash the soil out; landscaping fabric stops this.

[Yournamehere]

I'm surprised you had trouble with oak; we removed some platforms that were built on oak legs about twenty years ago and they were still solid - could of have used the posts again if we had needed to.

I've heard that some 'oak' is imported turkey oak rather than proper english oak and that it is made of mush.

[Steve Bullman]

I did this years ago, we used scaffolding poles for the posts.  Rammed them in with a 3.5t Volvo digger then just used railway sleepers for the timber.

[Yournamehere]

7 minutes ago, Steve Bullman said:

I did this years ago, we used scaffolding poles for the posts.  Rammed them in with a 3.5t Volvo digger then just used railway sleepers for the timber.

Ha yes! If ther's a digger on site that does save an awful lot of work.

[david lawrence]

Living willo

[david lawrence]

Living willow revetment ?

 

only needs trimmed back once a year

 

cheap easy and no heavy machinery required thus saving the ground

 

could be an option