The Neath & Tennant Canals Trust wishes to make the following observations:
Options 1, 2 & 4.
In the absence of interpretive information relating to Options 1, 2 and 4, the Trust is reliant upon the comments made at the drop-in event at Aberdulais on December 7th. The event was attended by a number of Trustees and other stakeholders who were advised individually by the representative of Binnies Uk Ltd and others that the removal of the Aqueduct and Weir would not have a significant impact in reducing the flood risk.
As such, given the status of the Aqueduct as a Listed structure and Ancient Monument together with its pivotal role in the reunification of a restored canal network, its removal in part or whole cannot be justified on the basis of the Hydraulic Model.
Likewise, the weir is an essential requirement for the survival of the Tennant Canal – as illustrated by the negative ecological effect on the waterway following its collapse – and should be restored.
The reference to the ‘increase in in-channel conveyance by removing the weir’ contrasts with the poorly maintained / silted river-bed above the aqueduct which clearly serves to impede the flow and to trap debris.
Option 5.
The title and explanation of this option – ‘to adapt the existing flood wall alongside the River Neath’ – is somewhat at odds with the associated maps which refer to the ‘removal’ of the wall. The desired change in flood-water levels in the adjacent areas presumably is achieved by diverting the excess flood water into the canal which would otherwise over-top the aqueduct. No reference is made, however, as to why the canal flooded with the comparatively ‘ limited volume’ that over-topped the underpass wall during Storm Dennis such that the residences of Canal Side flooded internally to a depth of 1m ( Section 19 report). As such it would seem doubtful that the canal could convey the excess resulting from the removal of the Neath Canal wall.
In light of the above no information is provided as to the proposed height and design of the wall; the capacity of the canal to convey the flood-water; the point of discharge of flood-water from the canal, and the impact of the flood-water on structures and the environment downstream.
Option 3.
Prior to the Storm Dennis event, the Aqueduct was last implicated in the flooding of Canal Side in 1998 following which the flood defences in the vicinity were improved and withstood the record flood in February 2020. The unmodified wall of the underpass did not!
The Trust notes that the erection of a new wall along the right banks of both rivers, serves to protect the residencies of Canal Side and the canal itself. The potential and logistics of restoring the Aqueduct conducted in a feasibility study by OPUS Ltd in 2012 includes means by which the integrity of such an enhanced flood wall can be assured during flood events whilst providing passage to navigation over a restored aqueduct at other times.
With respect to the flooding of adjacent areas, the Trust notes with interest that the area covered by the Hydraulic Model includes the historic listed Canal Depot adjacent to Tonna Lock, which it owns and maintains. The buildings are prone to being flooded, not least by the floodwater emanating from Aberdulais Basin over-topping the Neath Canal.
As such the provision of a flood gate across the railway arch together with another in the Neath Canal between the railway bridge and Dulais Fach Road would be desirable to address the flood risk to adjacent areas caused by the over-topping of the Basin.
In conclusion, The Trust strongly objects to Options 1, 2 and 4 but supports Options 3 and 5 subject to the concerns expressed relating to the capacity of the Tennant Canal to accommodate the excess flood-water.
Finally, in making the above observations, the Trust is mindful that the interests of the residents of Canal Side should be the paramount consideration. To do nothing and to rely on what little has been done to-date should not be an option.
