The newly-published Department for Infrastructure (DfI) second cycle Flood Risk Management Plan 2021-2027 reports that the risk of fluvial flooding from the River Foyle itself is deemed to be limited.
Tidal flooding from the lough is considered to be less of a potential problem than surface water indundations in the city in the short to medium term.
But it is still a potential hazard with the report noting that a major flooding event at Coolkeeragh power station could lead to a ‘significant infrastructure failure’.
“Londonderry has no formal sea defences, however, banks/quays act as a form of tidal defence that provides limited protection to low-lying areas of the city.
“These could overtop in more severe flood events, although tidal flood risk is much lower overall than combined fluvial and surface water flood risk and the standard of protection they offer is unknown.
“Further studies are being undertaken at Coolkeeragh Power Station on the coast, where flooding could lead to significant infrastructure failure. At Coolkeeragh, the railway embankment acts as a form of sea defence, although it is not recognised or managed as a formal flood defence,” the report states.
The greatest risk is from surface water flooding and flooding from smaller water courses with hundreds of homes and businesses on the cityside and Waterside identified as being under threat.