OPW: Office of Public Works
Oifig na nOibreacha Poiblí
Introduction
The Office of Public Works (OPW) is the lead state agency for flood risk management, and this document contributes to the implementation of the National Flood Risk Management Policy. The objective of the OPW is to ensure best international practice in relation flood risk management. The OPW recognises that there are other important considerations and stakeholders in the management of watercourses and infrastructure.
The Arterial Drainage Act, 1945 includes a requirement for the consent of the Commissioners of Public Works for the construction or alteration of bridges and culverts on all watercourses.
Issues and considerations
The OPW has produced a brochure entitled "A Guide for Applying for Consent under Section 50 of the Arterial Drainage Act, 1945". This guide identifies the main issues which should be considered in designing bridge and culvert structures. Significant changes in climate have been forecast. The predictions include changes in rainfall patterns, leading to increased flooding and droughts, and increases in sea levels. There are significant uncertainties in climate change predictions. It is anticipated that ongoing research and monitoring of climate change will lead to revised estimates of impacts.
PolicyThe OPW seeks to maintain the existing conveyance and storage capacities of channels and floodplains. The design and construction of those bridges and culverts necessary for access or deemed essential by the planning authority under a statutory plan should be such that flood risks up- and / or down-stream are not increased, or, where no other viable options exist, are restricted to acceptable levels, and should comply with any flood risk management objectives established for the area.
Plannning guidance has been prepared by the Department of the Environment, Heritage and Local Government and OPW on Flood Risk Management in the Planning Process.
The OPW will not consent to a bridge or culvert over an existing watercourse except where the requirements under the guidelines have been met.
A risk based approach on the likely impacts of climate change must be used in estimating design flood flows for bridge and culvert design.
Further Information
Further details are available from www.opw.ie.