Then and now: The “bush hole”, Castleconnell Fishery

Then and now: The “bush hole” area of the Castleconnell Fishery on the Lower River Shannon – map from the mid-1800’s compared with aerial photography from 2005.

The historical map shows this stretch of the river prior to the Shannon scheme and it is clear that this part of the river consisted of a large pool at this time – downstream of the raging “Falls of Doonass”. Indeed it looks very much like this area did during the floods of November 2009. It is clear that prior to the Shannon scheme that this stretch of the river was not “salmon water” even though this is the main salmon angling run on the much reduced Shannon of today.

Beat 6 and the “bush hole” area of the river as mapped in the mid-1800s. It is clear that this was a large swollen section of the river prior to the Shannon scheme. There was also an eel weir at this location.
Beat 6 and the “bush hole” as it is today. The river is much smaller due to the reduced post-Shannon scheme flow regime. The extensive instream physical modifications are also apparent.

In the modern aerial photograph we see a shrunken and highly modified river channel. The impact of the reduced post Shannon scheme flows is apparent, along with the instream modifications that were used by the ESB to mitigate for same. Since the Shannon scheme, the “old” River Shannon receives a compensation flow of 10 cumecs (cubic meters per second). This is equivalent to only a 1 in 50 year drought flow on the river prior to the construction of Parteen Regulating Weir. Clearly this has had a significant morphological impact on this river corridor; both as a consequence of the reduction in flow and due to the instream physical modifications which have been used to date. This has had significant consequences for both the ecology and amenity value of the river.

We are campaigning for the provision of increased and variable flows in the Old River Shannon to be delivered within the context of a sustainable management plan for the river and SAC

Castleconnell fishery
The “bush hole” during the November 2009 flood event which saw over 400 cumecs released from Parteen weir allowing the Old River Shannon to take back its former footprint and character.
Bush hole
The subject stretch of river with base compensation flow. Instream modifications and intrusive bankside signs are apparent.

This river channel is now a designated candidate Special Area of Conservation – and the reduced flows have favoured the encroachment of both annex 1 priority alluvial woodland [91E0] and the establishment of habitats used by salmon [1106] and lamprey species (Sea lamprey [1095], Brook lamprey [1096], River lamprey [1099]). It is also now – as mentioned above – undoubtedly the best salmon angling beat on the Lower Shannon. However, it is not achieving ‘Good Ecological Status’ due to the abstraction of water from this stretch for hydroelectric generation, and the low and unvaried compensation flow which is provided. Moreover the scale of instream physical modifications on this stretch reduces its ecological value. The salmon runs are also nothing like they once were, with the large spring salmon gone and overall runs only a fraction of historical quantities.

On a sustainably managed Lower River Shannon the “bush hole” must become something like the swollen pool of the past with the angling and conservation interests restored to the sections of river adjoining and upstream from here. The closer we get the situation back to what it was historically is the closer that we will get the Lower River Shannon back to ‘Good Ecological Status’. We also of course need new fish passes at the Shannon dams.

For additional information please see the following links:

We are campaigning for the provision of increased and variable flows in the Old River Shannon to be delivered within the context of a sustainable management plan for the river and SAC. We are also seeking the removal of many of the instream physical modifications in the river, to facilitate the restoration of a physically more naturalised river corridor in the interests of complying with the requirements of the Water Framework Directive and Habitats Directive.

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