John Paul Rooney

John Paul Rooney

South Dublin County Council


Following several flooding events in the Castlefield area, Roughan & O’Donovan (ROD) was appointed by South Dublin County Council to design a flood alleviation scheme, prepare contract documents and supervise construction of the works.


The scheme involved the construction of a flood alleviation culvert to convey part of the flow from the Ballycullen Stream during periods of heavy rainfall and reduce the risk of fluvial flooding in the Castlefield Manor housing estate.

The 1.6km of 1.5m diameter culvert begins at the existing surface water manhole located at Knocklyon FC and ties into the existing 1.5m diameter sewer located 1.5km downstream at Old Knocklyon Road.

We used the Infoworks RS and HecRas modelling packages to undertake a detailed hydrologic and hydraulic analysis of the catchment.

Microdrainage models were developed to determine the capacity of the existing drainage network in the area and to assess the size of the flood alleviation culvert required.

The scheme provides a 1 in 100 year standard of protection (+20% climate change allowance) against fluvial flooding for the residents of Castlefield Manor, Glenvara Park and Glenlyon Park.


The project site was located in a densely populated residential area, and several privately owned services had to be diverted to facilitate the construction of works.

Services provided:

  • Hydraulic assessment
  • Hydraulic and hydrological modelling (InfoWorks and HecRas)
  • Mapping (GIS)
  • Feasibility and conceptual design
  • Options study
  • Preliminary and detailed design
  • Statutory and legal services
  • Environmental and ecological assessment
  • Contract documents
  • Construction supervision
  • PSDP

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