Works continue on the construction of the Broad Burn (or Spey Burn as it is known local after the name of the distillery located on its banks) fish pass. The preparations for the works started over a year ago when consultants were appointed to draw up designs. This was a complex site with the conflicting requirements for water abstraction and fish passage. The change in river level between the intake and the stream bed below was around 1.8m and previously there was a high gradient “cascade” constructed from quarry boulders. Whilst spawning fish may have managed to get past the cascade if the burn level was right (high!) such conditions often don’t occur at the right time of the year. A more sustainable solution was required.
The rock cascade before – too steep to allow fish passage over a range of flows.
Speyburn Distillery commissioned local contractors to undertake the construction of the fish pass with the works starting last week.
The contractors came up with a very effective solution to bypass the major problem encountered whilst working in a burn – keeping the site dry. The intake pipe for the distillery cooling pond was extended upstream and a temporary dam built to divert the entire flow through the pond. This photo shows the upper fish pass headwall after the shuttering was removed. The paving below the old railway bridge was only exposed last year after the big spate in August, prior to that it had been covered in gravel.
Further headwalls under construction. The bed between the headwalls were subsequently filled with concrete and embedded boulders to create shallow pools.
The head difference between the walls was 30cm, with the pass extending to over 30m in length to provide a low enough gradient.
Excavator at work in the lower fish pass.
At the weekend the heavy overnight rain filled the Broad Burn to the extent that the diversionary pipe couldn’t cope with the entire flow. This provided a tantalising glimpse of how it would look with an operational flow. In due course the pools would be expected to accumulate gravel with the whole site soon taking on a more natural appearance.
Today the last major concrete pours were due for completion with only minor works remaining, including the smolt screens. This time next week the pass should be operational – fingers crossed.
The Broad Burn upstream of the Speyburn Distillery. There is excellent spawning gravel in this burn and it was always known locally as an important spawning burn, especially for big sea trout. We look forward to monitoring its development in future years.