OPW Flood Defence Schemes are generally carried out under the Arterial Drainage Act 1945 and the Arterial Drainage Amendment Act 1995, although in recent years some phases of schemes have been carried out by the Local Authorities under the Planning and Development Regulations. The OPW either works in association with the relevant Local Authorities or funds Local Authorities directly to undertake flood defence works.
The OPW Minor Flood Mitigation Works and Coastal Protection Schemeprovides funding to Local Authorities to undertake minor flood mitigation works or studies, costing less than €0.75 million each, to address localised flooding and coastal protection problems within their administrative areas.
The OPW carried out a number of arterial drainage schemes on catchments under the Arterial Drainage Act, 1945 , and flood defence schemes under the Arterial Drainage (Amendment) Act, 1995. Under section 37 of the 1945 Act, the OPW is required to maintain drainage works in proper repair and effective condition. This work is organised on a regional basis, with headquarters in Limerick, Headford, Co. Galway and Trim, Co. Meath.
The OPW carries out a range of environmental assessments for various flood risk management plans and projects.
The main assessments are:
Under the Arterial Drainage Acts, 1945 and 1995, and SI 122/2010 Regulations, construction and alteration of watercourses, bridges, weirs and embankments require the prior consent of the OPW. These legal requirements mainly serve to ensure that proposed construction and alteration projects do not increase the risk of flooding or have a negative impact on drainage of land.