Maintenance of rivers and other watercourses can have a positive role to play in preventing the deterioration of channel conveyance capacity. A regular maintenance programme to remove excess inorganic material and vegetation or remove debris and rubbish from river channels, and ensure that culvert screens are kept clear, can help reduce flood levels during flood events.
However, international evidence and expertise shows that maintenance on its own is not going to protect towns and would have had no beneficial effect on extreme flood events as experienced recently in Donegal. That being said, it is recognised that maintenance can assist in mitigating against the effects of less severe flood events and summer flooding.
The Office of Public Works, OPW, carries out a programme of Arterial Drainage Maintenance to a total of 11,500 km of river channel and approximately 730 km of embankments nationally. These maintenance works relate to arterial drainage schemes completed by the OPW under the Arterial Drainage Acts 1945 and 1995. The OPW has a statutory duty to maintain the completed schemes in proper repair and effective condition. The annual maintenance programme typically involves some clearance of vegetation and removal of silt build-up on an average five-year cycle. Each year, work is carried out to approximately 2,000 km of channel and about 200 structures around the country. Maintenance of all drainage schemes carried out under earlier Acts, known as Drainage Districts, is the responsibility of the relevant Local Authority.
In order to explore how state agencies can come together to address maintenance issues, the Shannon Flood Risk State Agency Co-ordination Working Group agreed to carry out some targeted maintenance activity. During September, works were carried out at the first of a series of locations on the River Shannon to remove silt and vegetation to enhance the conveyance capacity and navigation.
The current priorities of the OPW are to publish and implement Flood Risk Management Plans to address significant flood risk for 300 communities throughout Ireland and to deliver the capital investment programme of major flood defences that will protect thousands of properties during severe flood events. The OPW will continue to provide important funding to Local Authorities to deal with localised flooding issues through the Minor Flood Mitigation Works & Coastal Protection Scheme.
