Construction impacts of road-crossing structures on watercourses in special areas of conservation in Ireland

Abstract

The M3 motorway in Ireland was constructed between the years 2007 and 2010 and crosses a Special Area of Conservation, the River Boyne and its tributaries which are designated salmonid waters. The paper describes the measures taken to mitigate any potential impacts which the construction of the road scheme might have had on the aquatic environment. The success of the mitigation measures undertaken is assessed by: (a) comparing pre-construction, during-construction and post-construction water-quality data; (b) estimating the rate of sediment transport from motorway earthworks activities and deposition in adjacent watercourses; and (c) undertaking a post-construction monitoring of culvert performance. The analysis of the data suggests that the measures taken to protect the watercourses traversing M3 motorway have been successful in minimising the ecological impacts associated with the road scheme crossing of the Boyne watercourses.

Keywords:

• Culvert
• Mitigation
• River crossings
• Road
• Water

Acknowledgement

This research work has been funded through the National Roads Authority of Ireland Fellowship Programme.