Glenbeg Burn culvert and habitat improvements

In 2012 Jock Royan organised an auction on The Salmon Fishing Forum http://salmo.proboards.com/index.cgi . The funds raised in the auction were donated to the Spey Foundation with the proviso that it was allocated to habitat improvements.

I am now pleased to say that the donation has been invested in fencing on the lower Glenbeg Burn, works which will compliment fish passage improvements installed on the A95 culvert just to the south of Grantown.The culvert was constructed in the early 90s with the promise that baffles would be fitted. It took almost 20 years but the job has at last been completed.

A little about the Glenbeg Burn first. It joins the Spey on the left bank a short distance upstream of Grantown, the site thereby fulfilling Jocks request that the project should benefit as much of the river as possible. Habitat quality is excellent in the upper reaches although the spawning gravels are probably of a size more suited to trout with the occasional area of larger grade. In the not too distant past salmon were regularly seen spawning on the moorland fringe, several km upstream.

Excellent habitat in the upper Glenbeg Burn

Excellent habitat in the upper Glenbeg Burn. Salmon used to spawn up here and beyond

Further downstream the gradient was a little lower but the bankside cover was extremely good.

Very good habitat in the middle reaches of the burn. As in many Spey burns in this part of the catchment there is ideal growth of natural birch and alders along the banks

Very good habitat in the middle reaches of the burn. As in many Spey burns in this part of the catchment the natural birch and alders along the banks are present in ideal density to provide a good balance between light and shade.

All the Spey burns in the Grantown area are potentially very productive so it is important that fish are able to penetrate as far as possible to spawn. Our electrofishing results show a dramatic chane in the fish population above the culvert compared to below. There is a low population of salmon upstream, largely sustained by stocking although in some years a few salmon must get through the culvert to spawn.

The Glenbeg Burn culvert under the A95 is 38m long and has 0.7m of fall along its length. When we surveyed it before the installation of the baffles the maximum depth in the centre of the channel was just over 2″ and the water speed 2.1m/sec (showing my age with the mix of imperial and metric!), technically too fast and shallow for salmon or trout to pass, although the occasional fish was thought to make it through. Those measurements were taken at low flow, at higher flows there would be a greater depth but even faster water speeds. Salmon and trout are good at long distance swimming and short bursts but not so strong in the middle distance events. 2″ water is simply not deep enough for a salmon sized fish to generate sufficient propulsion to overcome gravity and the flow of water down the culvert. Scottish Government guidance states that for a culvert over 30m in length the maximum permissable water speed for salmon is 1.75m/sec for salmon over 55cm and for sea trout size fish it is 1.25m/sec.

The Glenbeg Burn culvert before the baffles were fitted: too fast and shallow

The Glenbeg Burn culvert before the baffles were fitted: too fast and shallow

Duncan Ferguson, Spey Fishery Board Operations manager, liaised with Bear Scotland who fitted the baffles with funding from Transport Scotland. 26 baffles were fitted at 1.5m intervals. The baffles were steel plates bolted and grouted to the culvert floor. Bear Scotland have the contract to maintain the trunk roads in this area and were very helpful in this instance.

Bear Scotland contractors fitting the baffles. The burn was dammed and overpumped to maintain a dry working zone.

Bear Scotland contractors fitting the baffles. The burn was dammed and overpumped to maintain a dry working zone.

Baffles fitted, water now significantly deeper, slower and with lots of resting places

Baffles fitted, water now significantly deeper, slower and with lots of resting places

Measurements taken after the fitting of the baffles showed that the water depth had doubled and the maximum water speed was 1m/sec. It will improve further once some substrate (cobbles, gravel etc) starts to accumulate between the baffles, roughening the flow even more.

Salmon and trout were always able to spawn below the culvert but there are about 2 miles of really good habitat upstream that we wanted fish to reach, hopefully some ancestral memory to spawn in the upper reaches remains within the stock.

The field below the road was used for grazing and silage and was unfenced on one side. The forum donation was used to fence the other bank to exclude stock access. A water trough was fitted with a feed from the burn.

Glenbeg Burn fencing. This will protect and improve the habitat downstream of the culvert.

Glenbeg Burn fencing. This will protect and improve the habitat downstream of the culvert.

Fencing further downstream

Fencing further downstream

Once complete a photo shoot for the local press was arranged. The story made the sports page in the Strathspey and Badenoch Herald a week later. I guess the editor wasn’t sure if this was an environment or a sports story but plumped for the later.

From the left:Duncan Ferguson, Grant Mortimer, Liz Henderson (Spey Catchment Initiative), Hugh Adcock (Strathspey Angling Improvement Association) and Brian Shaw

From the left:Duncan Ferguson, Grant Mortimer, Liz Henderson (Spey Catchment Initiative), Hugh Adcock (Strathspey Angling Improvement Association) and Brian Shaw

This was a great wee project and all at the Spey are very grateful for the donation from the forum which we think has been invested wisely. Thanks also to Bear Scotland and Trsonport Scotland. This was a real team effort with the bailiffs assisting with the fencing.

 

Authored by: Brian Shaw

There are 6 comments for this article
  1. Eric Hilton at 5:03 pm

    Well done Liz
    Keep up the great work… better than old EMU OTC days 😉
    Regards
    Eric

  2. Chris at 8:07 am

    Looks like a great project – keep up the good work!

  3. Pingback: Online auction is catalyst for improvements to Speyside road culvert | RAFTS
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  5. Graham Ritchie at 8:54 pm

    Excellent work Brian, good to see the money well spent on something which will have a lasting effect.

  6. Lawrence Belleni at 9:17 am

    Fantastic work, I was home a couple of weeks ago, and couldn’t resist having a look.

    I grew up on the banks of this burn, which has excellent natural riparian woodland habitat covering a large section of the sub-catchment, although it was previously even larger until a few years ago, and a fantastic sinous planform creating good in-water habitat. Great to see the potential for this burn to have its salmonid productivity maximised.

    Definately an untapped resource since the culvert/new road was put in!

    Looking forward to reading about more projects like this, and in my opinion, work like this is definately the right direction to maximising the fish stock, and not the hatchery, as your presentation in Aberlour Hall last year highlighted.

    I look forward to going on a walk to see/find evidence of spawning come the end of October/November time up the Glen.

    All the best,

    Lawrence

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