THE completed multi-agency report on the floods which engulfed Downpatrick and Newcastle last year is not expected to be completed until next March — 16 months after businesses and homes were swamped.
Independent consultants — who are compiling the report and provided their draft findings last week —said unprecedented rainfall across the south east area was to blame for the flooding which caused significant damage and destruction.
Triona O’Grady, from consultancy firm Jacobs, said the significant flooding the area experienced was triggered by exceptional rainfall, explaining that between October 26 and November 1, the region received more than double its average monthly rainfall, causing river levels to rise to record highs.
She said October was an exceptionally wet month for the south east area with twice the average monthly rainfall falling and that Northern Ireland experienced its wettest May to October on record since 1890.
She said some river levels were at their highest in 50 years, with heavy rain over the Quoile and Annacloy river catchments between October 26 and November 1resulting in significant flows in the rivers and their tributaries.
“These large flows led to increasing levels on the flood plan linked to the Quoile and its tributaries. A key tributary of the Quoile is the plank drain where flood levels and its flood plain rose to eventually flood a significant low lying area around Downpatrick,” she continued.
“Strangford Lough downstream and the Quoile tidal barrage experienced higher tides compared to Downpatrick, with the barrage preventing worse tidal flooding in Market Street.”
Turning to Newcastle, the consultant revealed the Tollymore waste water pumping station failed to cope with discharging surface water, with the Marguerite area in the resort badly impacted.
She said the heavy rain between October 26 and November 1 caused high flood levels in both the Burren and Shimna rivers, with the Burren reaching its highest level in 30 years at the Castlewellan Road.
“Surface water was the primary cause of the flooding in the resort and despite record high water levels, the Burren and Shimna flood alleviations schemes prevented river flooding,” said Ms O’Grady.
“The flooding that occurred behind the flood defences indicated that the cause was surface water, combined with the sewer network not having adequate capacity to drain the amount of rainfall which fell in the Burren and Shimna.”
Ms O’Grady said a multi-agency debrief was held in early March which looked at the emergency response, the key challenges faced and the aspects of the response that worked well and the challenges that occurred during the flooding emergency.
She said the concluded review report will bring forward items for consideration which will then be turned into recommendations going forward and will be categorised under multi-agency response and technical considerations.