Otters to get special passes to cross bridge

SPECIAL passes to facilitate the movement of otters and other mammals will be built following the construction of the new Shannon River Crossing linking Ballina and Killaloe, consulting engineers have confirmed.

An Bord Pleanála had requested Clare County Council to submit a cross section plan of the Kilmastulla River Bridge, demonstrating how it is proposed to ensure otters travel within the Special Area of Conservation (SAC) after construction.

The appeals board also asked the council to provide further details of the proposed culvert designs, demonstrating how safe otter and mammal passage will be facilitated.

In its response on behalf of the council, Roughan and O’Donovan Consulting Engineeers, pledged to provide otter/mammal passes at all watercourse crossings where required.

Ledges made of wood or metal planks will be at least 500mm wide, constructed at least 150mm above the one-in-five-year flood event and allow at least 600mm headroom.

The engineers explained where it is not possible to achieve the clearances or widths as noted, a separate underpass for mammals will be provided parallel to the watercourse culvert.

They stated all works adjacent to watercourses and preconstruction otter surveys will be carried out in accordance with the Guidelines for the Treatment of Otters prior to the Construction of National Road Schemes as published by the National Roads Authority (NRA).

Mammal passages will be provided on the east and west bank of the new crossing setback 4m from the bank under the bridge and 1.5m from the bank under the bridge for the Kilmastulla River.

Heritage Minister Jimmy Deenihan has granted the architects a derogation licence authorising disturbance and damage or destruction of breeding sites or resting places for otters on the basis there is no satisfactory alternative and with the stipulation that this licence will not be detrimental to the maintenance of the otter population.

The appeals’ board also requested the council to provide further information concerning the proposed drainage system, having regard to the potential impact on Natura 2000 sites and the SAC.

The architects insisted the road drainage for the Killaloe Bypass, Shannon Bridge Crossing and upgrading of the Ballina to Birdhill regional road will include a number of sustainable road drainage systems.

They argued these systems will prevent significant pollution to surface receiving waters and in particular the River Shannon SAC. Drainage systems include attenuation ponds, constructed wetlands, filter drains, open ditches, over-the-edge drainage, kerb, gully and carrier pipe systems and petrol interceptors.

Commenting on pollution control, the architects explained the catchment area for the new crossing drains the entire length of the new road between Roolagh Junction and Shantraud Junction. As run-off passes along the bridge, no flows will be permitted to discharge to the River Shannon.

In terms of accidental spillage, the architects said a pollution-control valve is proposed on the outlet of a local wetland pond. In the event of an emergency, this valve will be closed, with the pollutants confined within the road before they will be pumped and disposed of at a licensed facility by the local authority.

It is noted that all constructed wetland/attenuation ponds along other sections of the scheme will be constructed with a pollution-control valve fitted on the outlet to control and manage accidental spillage events.

The bridge will cross the River Shannon at the proposed location identified in the environmental impact study (EIS), where the river is about 143m wide. It will consist of a slender reinforced concrete deck supported by secondary steel beams connected to primary steel arches. It will be supported on four reinforced concrete piers in the River Shannon and two reinforced concrete abutments at the river banks.

The architects acknowledged the proposed Northern Limerick Distributor Road providing linkage and access to the University of Limerick campus between Coonagh and the N18 and the former Dublin Road near Castletroy had the potential to affect the Lower River Shannon SAC.

This scheme is currently at the route selection stage of development. The planned bridge is at least 18km from the proposed Shannon River Crossing at Killaloe.

“Given the distance between the two bridges, the requirements for both bridges to undergo EIS and Habitats Directive Assessment and the provision of detailed mitigation measures for the proposed scheme at Killaloe in order to ensure no significant impact on the SAC or water quality, it is considered there will be no cumulative impact between these developments,” stated the architects.

About 8.7km of hedgerows will be removed as a result of the proposed scheme, with about 2.5 hectares of woodland and scrub to be removed.

However, this will be replaced and enhanced by planting about 8.4 hectares of woodland and scrub and 7.2km of hedgerow.