Mayne River Balgriffin Flood Management Works

In order to facilitate a large scale residential development in Balgiffin, North County Dublin, DBFL in conjunction with HR Wallingford undertook a Flood Impact Assessment on a section of the Mayne River between Malahide Road and Hole in the Wall Road.

DBFL surveyed the river within the site immediately upstream and downstream of the site, and developed sections at regular intervals along the river.  An overall assessment of the river catchment was undertaken and to this end consultation with Dublin Airport personnel was necessary.  A site development layout together with all the available river information was sent to HR Wallingford so that they could construct a mathematical computer model of the river through the development site.

On completion of their model HR Wallingford were able to provide DBFL with a 100 year future flood contour within the development site.  DBFL overlaid this contour with the proposed development layout to identify areas where flooding of proposed buildings would occur.  An optimisation exercise was undertaken involving the reduction of the ground level in the immediate vicinity of the river channel such that flood storage benches of varying widths could be provided either side and along the length of the river channel.

DBFL issued revised river sections which incorporated the storage benches to HR Wallingford so that they could produce a revised future 100 year flood contour.  After a number of iterations a solution was derived which maintained the future 100 year flood storage volume within the site but corralled the flood water into open space areas.