The River Tolka has a history of flooding following heavy rainfall, which has been well documented after major flood events in 1954 and subsequent years. The river has been the subject of a number of investigations, and of most significance were those carried out in 1955 and 1986. Severe flooding from the Tolka River and its tributaries occurred in the Dublin City, Meath and Fingal areas in November 2000 and November 2002.
In July 2001 Dublin City Council commissioned the Greater Dublin Strategic Drainage Study (GDSDS), a multi-million euro engineering study of the strategic drainage requirements of the Greater Dublin area. A full study of the Tolka was not included in the GDSDS. In view of the November 2000 flood the OPW requested that it be included.
The Tolka River Flooding Study was underway when the November 2002 flood occurred. The consultants were asked to produce Interim Reports for all three local authorities concerned (Dublin City Council, Fingal County Council and Meath County Council) to identify works that could be undertaken straight away to reduce the risk of flooding in the worst affected areas. The Final Report on the Tolka was completed in November 2003 and this brought together many of the recommendations contained in the Interim Reports and also much additional information, which provided the basis for further decisions in relation to the catchment as a whole. As a result of the Interim Reports, works began in the Dublin City and County Meath areas in 2003 and were largely finished by 2009.
Works carried out in the Dublin City Council area included: new walls and embankments, replacement footbridge, widening of banks, lowering of Distillery Weir, scour damage repair and general channel maintenance. Responsibility for the maintenance of this scheme rests with Dublin City Council.