This is not a Newsletter as such but rather an up-date on the progress of smolts from spawning to the sea. It is long and detailed but then you do not have to read it all!
We are concerned with two barriers to safe progress down river
a) the possibility of the smolts being trapped and
b) the possibilities of the smolts being killed while navigating the turbines.
A trapped smolts.
As people may or may not know some 8,000 smolts were trapped within the gate slots in 2018. This was not the first such incident, but it was serious enough to be reported to SEPA. SEPA are the body who issue operating licences to SSE and have the power to enforce action to prevent unacceptable fish mortality. Below is SEPA’ s commentary on the situation..
This report follows the trapping of salmon smolts in the intake gate slots at Aigas and Kilmorack Power Stations on the River Beauly, and represents SSE’s current understanding of what happened and what it intends to do to try and prevent a recurrence.
The issue of trapped smolts was first identified by SSE staff on the 30th May and the below timeline details how the incident developed and was handled.
Timeline of Events
30th May 2018 (Wednesday) — SSE staff identify salmon smolts in the intake gate slots at Kilmorack Power Station.
31st May 2018 (Thursday) — Further investigation by SSE staff confirms that smolts are also present in the intake gate slots at Aigas. Alastair Stephen reports this issue to SEPA, initially by phone call to Dingwall and subsequently via the “SSEhydro” dedicated reporting email. SSE reported the same information to the Beauly District Salmon Fisheries Board (DSFB) Chairman, Clerk and Biologist shortly afterwards.
1st June 2018 (Friday)— Further investigation by SSE’s lain McMyn was undertaken at both Aigas and Kilmorack in order to determine a strategy for resolving the issue and to assess the numbers of fish involved. SSE staff along with Chris Conroy (Ness DSFB) agreed to convene on Monday 4th June and attempt to start moving the trapped smolts.
4th June 2018 (Monday)— Following some experimentation, a netting arrangement utilising an oblong frame with appropriately sized mesh net was used to begin removing the smolts (a number of other possible solutions were put forward and discounted — this had included the possibility of establishing a syphon arrangement leading into the adjacent Borland lift). Smolts were transferred into a transport tank (see attached photos) supplied by the Ness DSFB which was taken downstream periodically to the lower River Beauly where the fish were released. Significantly larger numbers at Aigas were observed compared to Kilmorack so it was decided to concentrate smolt rescue efforts at Aigas to begin with and then move to Kilmorack.
5th June 2018 (Tuesday) — Andrew Steele (SEPA) spoke to Alastair Stephen regarding the update and then visited site and suggested that another transport tank would be useful to speed up operations. This was provided by the Cromarty Firth DSFB along with their vehicle.
6th June 2018 (Wednesday) The smolt removal from Aigas and then later in the day at Kilmorack continued with the team from the fisheries and SSE working together to remove as many fish as possible
7th June 2018 (Thursday)— Marine Harvest, having been approached by Chris Conroy, provided a smolt pump which it was hoped would further assist in catching the smolts. Unfortunately this wasn’t the case as the fish could not be crowded into a sufficiently small area for the pump to operate effectively. Approximately 50 were removed by the pump. The original netting operation resumed at Aigas and latterly at Kilmorack
8th June 2018 (Friday) The team of individuals consisting of SSE staff and members of the Ness and Beauly Fisheries Trust and the Ness District Salmon Fisheries Board continued to work at Aigas. By this time approximately 8,500 smolts had been removed (approximately 1,500 from Kilmorack and 7,000 from Aigas).
11th June 2018 (Monday) After further discussion between Chris Conroy and Alastair Stephen, a spy ball camera was lowered into the three affected gate slots by SSE staff at Aigas and only 3 smolts were seen and so it was decided not to continue with further fish rescue.
Station Operation Prior to the Incident
Following a similar issue in 2016 it was thought that continuously running only one machine in low flows rather than periodically swapping machines, at both Aigas and Kilmorack could prevent smolts becoming trapped in the intake gate slots. The SSE Control Room have confirmed that from the 1st April 2018 onwards, only one machine at both Aigas and Kilmorack had run continuously at between 2MW and 6MW.
Additionally, it was identified that the gratings on top of the intake gate shafts were letting light into the slots and potentially attracting smolts. These gratings were changed to solid covers in 2016.
Thus neither idea solved the problem.
It is SSE’s opinion that a dry late spring and associated late smolt run contributed to a reoccurrence of this issue. Owing to a lack of water for generation at both Aigas and Kilmorack, each site has operated at between 2MW and 6MW. At 2MW, the water velocity past the intake gate slot entrance will be relatively low which increases the chances of smolts finding their way into the slot. It would appear that a change from winter conditions in April, to summer conditions in May, and the corresponding drop off in generation, coinciding with the large run of smolts as the water warmed up has led to this unfortunate incident.
Measures to Prevent a Reoccurrence
SSE Renewable Generation is firmly committed to understanding the reasons behind this issue and identifying further means in order to reduce the likelihood of it happening again. This shall entail specialist input and advice and as such it will take time to determine the next steps. A number of potential mitigations are currently under active consideration. In addition, SSE recognise the issue of being able to demonstrate the effectiveness of any mitigation measure(s) that are developed. SSE shall ensure that SEPA and the Beauly DSFB are fully engaged in this process and welcome their input at all stages.
Since receiving the above the Fishery Board, SSE and SEPA have met and agreed a way forward with regard to the trapping of smolts. This includes physical changes to the entrance of the gate slots and of course regular monitoring. These should be in operation for winter/spring 2018/2019..
It should be noted that SSE did attempt to operate the turbines at higher velocities during the hours of darkness when the smolts are running but had insufficient water for substantial increases. They have also been completely open and honest about the incident.
- B) Smolt Mortality & The Turbines.
The basic problem is that we have very little hard information. There has only been one test that we know of on the Beauly which put a small number of smolts through the dams. This took place during the 1980s and only at a high generation level. Only one smolt died. We also have the results of a survey of 100 smolts at Tor Achilty. Tor Achilty is similar to Aigas and Kilmorack in that the smolts have to navigate the turbines but quite different in terms of flow and profile of the dam. The survey had found that 2.1MW load (a low rate) that after 1 hour 90% of the smolts survived and after 48 hours 73.5% survived. Whereas at 4MW 99.2% survived and after 48 hours 90.1% survived. The survival figures are averages.
However at a low level the loss was around 27%.
The situation is complicated by the fact that declining return rates of smolts is also a marine problem. Marine survival is now only 5% compared to a former 15-20%. The returning population of adult fish 3500/4000 is commensurate with the low rates smolt survival. The Beauly used to have 7000 to 8000 fish returning to the river.
It has been decided at recent meetings between the Board, SSE and SEPA there should be a survey of all the information available on smolts negotiating turbines, to be carried out by an independent organization. Depending on the outcome of this survey a decision will be made as to whether to test a larger number of smolts going through the Beauly dams. At present we do not even have a time table for the start of this information gathering, though clearly it needs to be sooner rather than later.
The BAC Committee believes that unless the survey of information comes up with a situation identical to ours, testing of smolts going through the turbines is a necessity and we would like this to be at 6MW, 4MW and 2.1MW.
Given the low level of smolts returning it is beholden on all of us to try to ensure that as many smolts as possible make it to the sea and that in our case means ensuring they can navigate the dams.