Cork City and its hidden Valley and why you you should say NO to the proposed flood defence!

Only two more days to lodge your submission to OPW!

This updated short explores how the unique integration between the waters of the river, sea, groundwater and the Lee buried valley aquifer below the low lying central City area, some 140m deep and as wide as the city, filled with glaciofluvial gravels and water. This gorge once ran to Youghal, the original outflow from the Lee.
The tidal waters rise and fall daily beneath the city to within 300mm of the street, in synch with what you see in the river, but with a short lag. As the tide goes out, the tidal ground water level beneath the city can remain higher than that of the river. What works in Fermoy or Clonmel will not work here.
The experiment confirms our belief that the ‘walls’ as they are now known will provide little defence to a tidal or fluvial event no matter how high they build them. Sealing the walls and drains will do little, it is all one water mass and Corks belly is not impermeable. Water pressure will exert significant pressure on the culverts, the footings and our very streets as levels inevitably rise.
Many building owners will tell you that their buildings do get damp after a few consecutive high tides but dry out again.
We need to look at the other 95 km of river for solutions, with multidisciplinary input. Catchment management and tidal barrier must be considered as sea levels rise due to global warming somewhere between 1 and 6m, most likely a couple, before the end of this century. Managing the river upstream with using proven interventions such as dam management, appropriate wetland planting, storage, hedgerows, trees can contribute greatly to reducing the risks. Think before spending €140m using crude hard engineering methods that will do untold damage to the city fabric and its relationship with its greatest asset, the Lee.
Make up your own mind, review the proposed works and help inform the promoters the OPW by letting your views known, telling how water already comes up in your property etc., by 6th April 2017. Details found at www.savecorkcity.org
• What will the visual impact be?
• To what extent will Cork’s heritage suffer or be destroyed as a consequence?
• How will this affect the amenities the river serves?
• What affect will these walls have on our local economy and tourism?
• How will they police urban spaces behind walls designed to be 1.8m higher than present street level then extended by another metre (Grenville place) ?
And most importantly of all – ASK: WILL THESE WALLS ACTUALLY WORK?
A special word of thanks to Prof. Alistair Allen, for use of the aquifer and groundwater level oscillation diagrams