The following Press Release has just been issued by the River Don Trust
"The salmon population in the Aberdeenshire's River Don is already taking advantage of a new fish pass, allowing them far easier access to an important tributary for spawning. This follows the installation of a new pass in late summer through a vehicle ford over the Ernan Burn on Edinglassie Estate.
The pass should enable the river's salmon to utilise to maximum extent over three miles of spawning and juvenile habitat.
The area in the upper part of the river's catchment is believed to be particularly important for spring salmon, the most fragile component of the Don's stocks of migratory fish.
Jamie Urquhart, Biologist for the River Don Trust, explained: "The ford in question was clearly a major obstacle for salmon to negotiate as they tried to migrate upstream. Having obtained the necessary consents from SEPA, we carried out the work ourselves, with support and private funding from the Don District Salmon Fishery Board and Edinglassie Estate respectively, using a low-tech, low-cost design employing locally sourced larch timber and locally won stone. This complied with the Estate's wish for a low visual impact whilst maintaining the aesthetics of the upland terrain".
Mr Urquhart continued: "It is pleasing that this month we have already seen several pairs of adult salmon upstream of the pass. Previously this tributary has been stocked with juvenile hatchery fish. Adult salmon homing back to this area should now be able to ascend through the fish pass at will and spawn naturally – a much more desirable situation than trying to replicate nature through the use of hatchery-bred fish. This exercise has established a skill set within the Trust which will serve us well in undertaking further similar works in the future"
(http://i47.photobucket.com/albums/f163/collieston/trust/Day-1-023w-1.jpg)
Before
(http://i47.photobucket.com/albums/f163/collieston/trust/027w.jpg)
and after
The upper ford replacement is really little different from an Irish Bridge with a single pipe channel. The Irish Bridge style always suffers from shifting bedload blocking the pipe entries and whenever the road bed is overtopped in a spate the surface needed to be in concrete to stop it being washed away. In this case there seems to be unbound as-dug or crusher-run material and I wonder how long it will stay since even a minor spate will lead to overtopping. The flow level control weir below the new crossing is not much less of an obstacle than the last ford and as it becomes undercut might develop the same height difference. I wonder how it will all look three years from now.
Good work! :D
Odd though, from the photo that old ford does not look as if it would be a barrier to salmon other than in very low water, certainly no more than the new weir downstream of the new bridge. It is difficult to gauge the scale and water depths from a photo though.
Quote from: admin on December 04, 2012, 03:08:08 PM
Good work! :D
Odd though, from the photo that old ford does not look as if it would be a barrier to salmon other than in very low water, certainly no more than the new weir downstream of the new bridge. It is difficult to gauge the scale and water depths from a photo though.
That was my thought too Fred. They have to ascend a much bigger obstacle on the Endrick.
That was not an obstacle to migrating salmon and the "new" installation is likely to cause more problems than the old one.
Quote from: Malcolm on December 04, 2012, 04:09:51 PM
That was my thought too Fred. They have to ascend a much bigger obstacle on the Endrick.
It may depend on the water depth below the fall Malcolm. if the old pool was shallow during low water the fish may not have been able to get up enough speed to jump over. I'm not sure how they do that though, so that could be nonsense. :lol: Anyway, in high water than old weir would vanish I think and the fish would have swam over it easily. Like Vaughan I do wonder if that bridge will still be there after a big flood. It looks like it will block easily too as there does not seem to be a lot of "headroom" underneath. Again it is hard to say from a photo.
Quote from: Bobfly on December 04, 2012, 03:07:47 PM
I wonder how it will all look three years from now.
I have seen work like this carried out on another stream up in the north west where they have created pools using boulders graded down stream to allow the fish to swim up into the pools. A member of this forum was involved with the planning and implementation of this and after many winters and spates they are still there. It is pretty impressive work, very natural looking, that was done without fanfare and has greatly improved the habitat for all animals and fish, not just salmon or making vehicle access more reliable for grouse shooters in wet weather. The hideous and unnatural burnt patterns and eroded bulldozed tracks on the hill in the above photos may indicate this is the principle use of the land.
Infilling with large rocks set into the stream bed to make boulder cascades would be a reliable and simple way of dealing with the previous ford, which was not much of a barrier in the first place if fish movement was at higher flows. I have a hatred of Irish Bridge types of culverted fords as they always always give trouble by blocking up at the intakes and scouring down at the outfalls. A complete menace when there is any likelihood of branches or debris coming down as the culverts block straightaway and you then have a higher barrier dam structure across the stream than the level of the original fords.
Quote from: Bobfly on December 05, 2012, 12:16:02 PM
Infilling with large rocks set into the stream bed to make boulder cascades would be a reliable and simple way of dealing with the previous ford, which was not much of a barrier in the first place if fish movement was at higher flows. I have a hatred of Irish Bridge types of culverted fords as they always always give trouble by blocking up at the intakes and scouring down at the outfalls. A complete menace when there is any likelihood of branches or debris coming down as the culverts block straightaway and you then have a higher barrier dam structure across the stream than the level of the original fords.
Agreed, fish movement on such a stream will only be at higher flows anyway. What has been done is a "change" not an improvement and it will likely cause more problems than it purportedly solves.
Scouring may be a problem but only time will tell and it should be fairly easy to clear away.
No chance of trees and branches blocking the culvert looking at the landscape above the bridge. I can see they have tried to replace one slightly large obstacle with two smaller ones and it will help in lower water.
As previously said I would like to see it in a couple of years and it has created a couple of nice pools which will help the trout as well.
Billy
I think we probably all realise this was not the best or the most lasting solution, but a few things must be borne in mind. For a start the estate might not have allowed the more lasting "boulder solution" as this would not have improved vehicle access in fact it may well have barred it altogether. The upper Don in that area is little more than a burn and the serious salmon fishing is all well downstream, thus fishing may not count for much of the income. This construction at least allows, for the time being, sightly improved fish access (fish HAVE for the first time been seen above it in LOW water) and much improved vehicle access to the grouse moors.
The Don trust is run by volunteers and people like Iain (machar) and diverdave (Dave) give their time freely and generously. I have nothing but respect and admiration for these guys. Raising money for such projects is always going to be difficult and while we as a forum have supported them by auctions etc this is by no means typical behaviour. As a local I have always believed that in spite of issues like poor access, giant hogweed, high permit prices for trout fishing etc that seem to plague the Don it is better to try to focus on the bigger picture and that locals should do more to support their local river. I have tried to support the trust through my fly line sales and have thus put my hand in my pocket on more than one occasion, but sadly this also is not typical. There is only so much one fishing forum and one individual can do! I am now no longer a local and my own duties will now move on with me as they rightly should.
If local anglers and angling businesses were more prepared to support the trust perhaps a proper bridge and a better fish pass could have been built here. Perhaps some locals who are critical of the Don trust should take a long hard look in the mirror and ask themselves what they have actually done?
That's a problem in a lot of places Fred. We don't have problems like that here as virtually all clubs allow part of the club fees to be "worked off" in the form of a minimum two days work on a club water so you can usually get quite a few bodies at least, but they still need planning and supervision. As the vast majority of waters are run and controlled by clubs here things tend to work out fairly well. It may however sometimes be difficult obtaining permission for various things in some places. Things that directly affect landowners, ( although they have no say in the running of a water ), have to be discussed and planned well in advance of any work.
There are always people clamouring to come on electro-fishing work parties, but not so many for heaving boulders or litter clean-ups etc.
The idea of setting in a boulder cascade in that location would be to build entirely below the existing ford track crossing which also then supports the cross log and its existing ford formed by the deposition above. The ford is not affected and the stream below is brought up a little through the use of the boulders. The Canadians and western US Forest Services have done a lot of this sort of work related to culvert outfall scouring leaving a waterfall spouting out of a pipe and correcting this; also by installing zigzag baffle ridges inside larger Armco invert D pipe crossings if these have a paved smooth insert. In this particular upland moorland setting you are not going to be having woody debris coming down but any Irish Bridge is always very susceptible to silting up at the pipe entries as the moving bedload in these streams is quite considerable in spates and material will build across above the topside. In the longer term a new "ford" may very well be created upstream from the new installation.
That's great information Vaughan. The high levels and diversity of expertise in our community never ceases to amaze me. :D