Flood Wall - Issues

Below is an update from the CRA. Please read the update carefully.

S2S Works - Wooden Bridge to Causeway Road

Last week we informed residents of the “official launch” of the incomplete cycle track and detailed the safety concerns that prevented us from attending that launch.  (Click here)

Yesterday we updated residents in relation to a number of the incomplete aspects of the overall scheme including issues related to – the new public lighting, new footpaths, the Car Park in St Anne’s Park and parking bays, the “renovated” Tram Shelter, the defects and ponding issues with newly resurfaced road and the new watermain.  (Click here)

One of the significant elements of the S2S works on the Clontarf Road was the provision of flood defence measures designed to provide continuous protection against the risk of flood.  This “continuous protection” has four elements –

(1) a ramp on Causeway Road, (2) bunds leading from that ramp to (3) the new flood defence wall, and (4) a floodgate on the Bull Bridge.  

While the ramp on the Causeway Road has been completed, the bunds are not yet complete and the flood gate on the Bull Bridge is yet to be installed.  

The position in relation to the flood defence wall is significantly more complex.  

The flood defence wall was to be built to a finished height of 4.25mODM.  As sections of the wall were built it became clear that the height was not acceptable.  Despite recent newspaper reports lamenting the loss of views for motorists, the visual link between the Park and the Biosphere was lost to everyone except those on the new cycle track or seaside footpath.  The loss of the visual amenity to wheelchair users and walkers in the Park was of particular concern in this regard. 

Agreement Made

Most residents will be aware that agreement was reached with DCC that the flood defence wall would be reduced by 300mm from Causeway Road end to just past the Lodge in the Park.  

This agreement was subject to: 

(1) confirmation that the Park could contain any flood water that might arise in an extreme weather event, (2) satisfying health and safety standards, (3) and obtaining the necessary Planning Permission.  

The blue line on the new wall indicates the agreed final finished height, including capping, of the wall. 

Floodplain in St Anne’s Park 

DCC confirmed in May 2016 that they were satisfied that the Park could contain any such flood water.  It should be noted that in such an event four fifths of the flood water in the Park would have come from the Naniken and Santry Rivers in the first instance!

Health and Safety Issues 

In the original design of the flood wall, it was only viewed from a sea side perspective.  A height over finished footpath was never specified.  As a result, when the wall was completed a number of sections of wall along the entire length were extremely low.  When the new wall was cut opposite the duck pond to show the 300mm reduction it too was extremely low.   

An independent Stage 2 Road Safety Audit was undertaken in January 2017 and it identified a number of safety issues with the scheme as designed.  One significant issue related to the low wall height over finished footpath which the report considered “may be a hazard to pedestrians”.  This issue had not been addressed in the original Stage 2 Audit for the scheme and would not have been addressed until post construction had the agreement to lower the wall not been reached.  

DCC subsequently decided a height of 500mm over finished footpath was appropriate in a coastal location of this type.  On reviewing the flood wall using this figure, DCC identified 5 sections of the wall, totalling 387m, which did not reach this standard.  Only one section, opposite the duck pond, totalling 160m, of this related to the proposed lowered section of the flood wall.  The remaining four sections, totalling 227m, related to the flood defence wall as designed and approved in the original planning permission for these works.  

Solutions

Unfortunately, DCC did not convey the H&S issue back to the community with a view to working together to find a solution to the problem.  Instead they drew up PP looking to install a railing along the entire 1.6m of the flood defence wall at a cost of and additional €.5m.  

At the request of the community groups, DCC subsequently gave us details of the precise sections of wall that were below the 500mm minimum and details of how far below this level each area was.  These areas were reviewed on site by the community representatives on the EMLC.  The amount of the adjustment needed ranged from approximately 20mm to 150mm.  The length of the adjustments at the upper end of this range was not significant.  The areas in question were also fairly level.  Based on the feedback we received from the community groups involved in this project and local residents, we informed DCC that we had no objection to the areas in question from Seafield Road to Mt Prospect Avenue being raised to reach the 500mm minimum required.  The amounts involved were so insignificant that DCC did not require PP to make these adjustments.  This work has now been carried out.  We are not aware of anyone having an issue with the heights along this section.