River Erosion

[liamjordan]

Having the river run right round one of our fields in an arc we get a lot of problems with river erosion, most of it we have combatted by filling and putting willow stems in, one bad corner was stacked with large concrete blocks, didnt look nice to begin with but how its grown over and looks good.

 

But anyway heres my point, saw this today on the opposite bank, such a shame as a few years a go this oak tree was looking really healthy.

 

Wont be long before hes in.

[Ian Flatters]

Very hard one rivers as water will always find a way to get through... Willow stems seem to be the way forward but obviously cost money in management. Concrete will always evidently fall fowl to scouring effect. Seems like we can only do one of 2 things watch it or try to slow it down.

[Charlieh]

thing is we have wrecked all our rivers, if that oak falls in will it be left? probably not as either farmer, fishing club or some other body will come along and remove it,

 

then in the next breath said people will be complaining that the river is coming faster than it ever did, and eroding quicker, why is this, as we have got to the point of manacuring our rivers, there is no natural flow attenuation in the channels, no woody material that slows flows, causes scour pools, cleans gravels for inverts and spawning fish,

 

Hard engineering isnt the answer either, concrete sleepers will solve one farmers problems and make everyone downstream of his worse, if he had sought advice and used soft engineering and flow deflectors to slow the water and reduce the energy of the water before the bend it would have probably recovered naturally,

 

this tree is going into a canalised section of river to force new scour pools out and create some fish cover

[Charlieh]

similar job on another river, fish cover and to aid reducing the energy of the river along the banks,

[Charlieh]

i admire your using the willow, its a good start, but getting upset about trees falling into the river is not good, we now try and retain as much woody material in the river channels as possible in consulation with the Environment Agency, but its all about getting the whole river system functioning properly and to a large extent that include natural erosion, look on that oak falling in as an opportunity speak to the landowner and ask if you can fasten it upsteam slightly to help slow the flow along the toe of the bank, whilst it wont stop the erosion instantly like conrete or such it will allow the bank to start to slump and regain a more natural profile rather than that of a cliff face,

 

 

any pics of the willow work you have done?

 

 

and remember conservation can involve big kit to!

 

and the final masterpeice, an engineered log jam

[liamjordan]

Some great pics there charlie! Thats the sort of thing i would love to do more of!

 

Just took these pics, this was done quite a long time ago, back when i was a very young un , amazing how well its worked, big stems of willow lay across the bank, steak and tied down with wire rope, the steaks have washed away now.

 

The last pic is similar to some of the stuff you have been doing, but this ones natural and we dont have any intention of moving it

[tommer9]

Really really interesting thread. Very informative. Charlieh, is there any adverse affect from dropping large amounts of hardwood into water courses (at the risk of sounding stupid.....) from tannins etc, or because the water is fast moving its not an issue, if you see what i mean?

[dangerous brian]

Tom i recon the NRA might get a bit P....y if you go dropping huge lumps of timber into the national river system.

[Charlieh]

Really really interesting thread. Very informative. Charlieh, is there any adverse affect from dropping large amounts of hardwood into water courses (at the risk of sounding stupid.....) from tannins etc, or because the water is fast moving its not an issue, if you see what i mean?

 

its never been a problem as far as im aware, but i must admit its not something i have ever heard discussed, so i will fire off an email and ask some questions, this technique is used widely in the US/Canada and places like Spain, and i havent every heard of any negative impacts, infact the numbers and quality of invertebrates has increased significantly, which would indicate that there isnt a problem

 

Tom i recon the NRA might get a bit P....y if you go dropping huge lumps of timber into the national river system.

 

NRA thats very 1990's, as i mentioned this is technqiue that has been implemented with the EA's consent as on main rivers you need permission to carry this work out, and even on non main river we consult them as a matter of courtesy. On several rivers EA have actually carried out this kind of work themselves

 

 

here are a few pics of a scheme from last spring, felled a sycamore and bundled up the brash, and staked it to the bank and in these pics you can see that the silt has built up in the brash and is starting to vegitate, so the bank will slump over the top of it gradually,

 

i will add this as my last picture, this is the farmers worst nightmare and a site im working on currently, the river has created a secondary channel that is now the main channel, and has formed a huge scour pool and is eating into his field at an accelerating rate, from the farmers point of view its awefull, from a river geomorphology point of view its great, as the river is acting naturally and moving around in the floodplain, its also adding vital new gravels to the river, this is also slowing the flow of the river and as a result will be helping to mitigate flood effects downstream, but will have to have some remedial works on it to prevent the landowner driving concrete railway sleepers into the bank as protection

 

[Mattsnaturalrivers]

Nice works, always good to see other peoples river projects, heres a few of mine putting trees in the river and root buttresses as well as upstream log deflectors to increase scour and sinuosity. Not done a lot with willow due to maintenance issues but always good to see techniques like this and the tree kickers that don't often get a chance to try.