River Brosna Special Area of Study 2014


The River Brosna has a catchment area of 1,273kmand is the 3rd largest tributary of the River Shannon. It rises in Lough Owel north of Mullingar and flows through Mullingar into Lough Ennell and south-west through the towns of Kilbeggan, Clara, and Ferbane to join the Shannon at Shannon harbour. This river was formerly one of the best trout rivers in Ireland, and was also known as a salmon fishery in its own right. However, the river was subjected to a major arterial drainage scheme in the 1960’s, and has suffered as a result of water quality problems. These issues have acted in combination with fish passage issues at the Shannon dams to ensure that salmon runs to this sub-catchment are now at negligible levels.

River Brosna at Ferbane, July 2013
River Brosna at Ferbane, July 2013, with water quality issues apparent

Juvenile salmon have been regularly stocked by ESB into the River Brosna catchment since 1961, and to date several million unfed fry, parr and smolts have been stocked here. In a catchment wide survey completed in 1999 (following two years of no restocking) it was found that juvenile salmon derived from natural spawning were present as far upstream as Kilbeggan. However, this situation has deteriorated markedly in the last 15 years and it is thought that very few salmon now enter the River Brosna to spawn. The main reasons for this are clearly located at the ESB dams; however there are also relevant issues that need to be addressed in the River Brosna catchment itself. In addition to salmon and European eel, the River Brosna is also known for its runs of migratory trout (“croneen”) which enter the system from July onwards during suitable water conditions. The Brosna should be a nationally important resource in terms of biodiversity and recreational opportunities. However, decades of mismanagement have resulted in serious damage to this catchment and its fisheries and ecological interests.

The River Brosna is going to be our special area for study in 2014 and we will be highlighting issues in this catchment which continue to act cumulatively – with fish passage and water management issues at the Shannon dams – to prevent the restoration of salmon runs to this catchment

Prior to the AARC Project on the River Bunowen, the River Brosna was the ESB’s “special area for study” as part of the River Shannon Salmon (Mis-)Management Programme. The River Brosna is going to be our special area for study in 2014 and we will be highlighting issues in this catchment which continue to act cumulatively – along with fish passage and water management issues at the Shannon dams – to prevent the restoration of salmon runs to this catchment. Unlike the AARC project we can be upfront in naming the Shannon Scheme as the main reason why there are no salmon in the upper Shannon. However, there are other issues such as arterial drainage and drainage maintenance, water quality, small hydro schemes and the presence of other barriers to migration that work, in combination with poor fish passage and water management at the dams, to ensure that this river no longer supports significant number of salmon. We will be highlighting these issues during our current study of the virtually forgotten (in terms of fisheries management) River Brosna catchment. We will also comment on pressures affecting other aquatic species such as migratory trout, eels, and lampreys.

Belmont weir, March 2014

The photos below show Belmont Weir on the River Brosna during Mid-March 2014. This weir diverts a significant part of the discharge on this river to a small hydroelectric scheme. There are a number of small hydroelectric schemes like this on the main channel of the River Brosna, with Belmont being the first one upstream from the River Shannon. Water levels were still high at the time of taking these photos: however the river is likely to run off over the next week and the smolt run (derived mainly from fry released by the ESB in 2012) will commence shortly. Juvenile trout will also be migrating downstream (i.e. croneen “smolts”).

No smolt screens and blocked fish pass

From the photos above it can be noted that the fish pass at this site was blocked with trees and other debris. More importantly, for this time of year, we noted that there were no smolt screens present (to keep downstream migrating smolts away from these turbines). There is still time however to fix this issue, as we are just at the very start of the 2014 smolt run. It is possible that smolt screens could not be installed yet due to the recent high discharges in the river. It is also likely that the fish pass (upstream migrants) only became blocked recently, and water levels would need to go down for it to be safe to clear this.

It will be interesting to see if smolt screens will be installed at Belmont weir and at the other hydro sites on the River Brosna next week. We are quite sure they won’t and we expect to be highlighting this in due course.

Eel turbine mortality

It is noted that all the silver eels migrating downstream from Lough Ennell and Lough Owel follow the headrace here at Belmont weir to be subjected to turbine mortality. There are no screens for eels here, or no system to divert eels away from the turbines. Eels arriving here could also have entered turbines at Kilbeggan and Clara, before passing though the Belmont scheme and then the Shannon scheme (or alternatively coghill net mortality or sub lethal effects for the 20% or so that end up in the ESB’s trap and overland transport scheme). It is noted that the European eel is a critically endangered species, and this management approach is just not good enough. Why are these issues affecting eels not being addressed?

The eel management approach taken in Ireland comprised of getting rid of the traditional fisheries that connected communities to the eels, and involved doing nothing about non-fishing eel mortality such as turbine passage mortality at hydro schemes like this scheme at Belmont weir. The UK Environmental Agency see addressing non-fishery sources of mortality as being their highest priority, while seeking to maintain a sustainable and economically viable eel fishery. Inland Fisheries Ireland did the complete opposite of this: they just banned eel fishing and did almost nothing else to help the European eel. Inland Fisheries Ireland allow the ESB and small hydro operators like this one at Belmont weir to get away without providing screening or fish bypasses at their hydroelectric schemes. It was much easier to take on the traditional fishermen, who had a vested interest in safeguarding the future of the European eel, rather than to take on the ESB and other commercial interests who think nothing of sending an endangered species through their turbines.

River Brosna, Belmont Weir, Entrance to headrace. No smolt or eel screens being operated.
River Brosna, Belmont Weir, Entrance to headrace. No smolt or eel screens being operated.

No downstream fish passage facilities at the Shannon dams

Likewise, there are of course no downstream fish passes at the ESB facilities at Ardnacrusha or Parteen. All downstream migrating smolts have to go through the turbines, and all salmon kelts die in front of the trash racks at Ardnacrusha. The ESB only trucks a small percentage of eels (<30%) around the turbines, with the rest subjected to turbine mortality. The eels caught and trucked around also have a significant mortality factor, and the turbines kill and damage a disproportionate percentage of the large females, crucial to the survival of the species. It is a key message of our group to make sure that everyone who cares about salmon and eels in the Shannon catchment understands these blunt facts.

Planned work

We will be monitoring Belmont weir and other areas of the River Brosna catchment as part of our River Brosna Special Area of Study 2014. We will be highlighting issues affecting this catchment as an example of the challenges facing rivers in Ireland, as a result of environmental pressures and poor management/regulatory enforcement. The River Brosna is ideal for such a study as it unfortunately has all the significant pressures affecting Irish Rivers in this one catchment. By raising awareness of these issues and highlighting the failures of the regulatory agencies in addressing same, we hope to contribute to informing more effective management protocols for Irish rivers, and in particular rivers in the River Shannon catchment, in the future. The main problems for migratory fish on the River Shannon are clearly at the Shannon dams. However, there are also problems in the middle and upper Shannon catchment and we will be highlighting these issues with this case study of the River Brosna sub-catchment.

Clonsingle weir on the River Brosna, at the outflow of Lough Ennel
Clonsingle weir on the River Brosna, at the outflow of Lough Ennell

Further reading

5 Thoughts

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s