Lee Catchment Flood Risk Assessment and Management Study

Study background

The Lee CFRAMS is one of three pilot studies being carried out to meet the requirements of the EU Floods Directive which was introduced on the 26 November 2007. The study will focus on urban areas known to have experienced flooding in the past and areas subject to significant development pressure both now and in the future. The extent of the study area is shown in the map below.

Work on the study started in August 2006 and will continue until late 2008 when a Catchment Flood Risk Management Plan (CFRMP) will be published. This plan will define the levels of existing and future flood risk in the Lee Catchment and set out how this will be managed both now and into the future.

Flood Risk in the Lee Catchment

Significant flooding occurs throughout the Lee catchment from time to time, affecting a number of towns and villages. The low lying areas of Cork City Centre are in particular regularly affected by tidal flooding, for example, the tidal flood event of October 2004. Much of the flooding occurs during adverse weather conditions. Heavy rainfall causes high river flows. Low pressure and strong easterly winds cause surges in Cork Harbour. High tides also impact on the level of flooding. Flood risk can also be increased by local conditions. These include bridges and culverts restricting high flows, debris causing blockages and environmental and land use changes. A table of the most significant recent flooding in the catchment is shown below. For more information on each of these flood events please visit the OPW's National Flood Hazard Mapping website.

Flood event	Main flood mechanism	Rivers affected	Areas affected
August 1986	Fluvial	Lee; Sullane; Laney and Shournagh	Baile Mhic Íre; Macroom; Ballincollig; Blarney and Cork City
November 2000	Fluvial	Lee; Owenacurra; Martin and Shournagh	Midleton; Watergrasshill; Fivemilebridge; Ballinhassig; Ballygarvan; Cork City; Ballincollig and Blarney
November 2002	Fluvial	Lee; Glashaboy; Owenboy; Ballybrack and Butlerstown	Douglas; Carrigaline; Ballygarvan; Ballinhassig; Monkstown-Passage West and Riverstown
October 2004	Tidal	Lower Lee and Cork Harbour	Cork City; Cobh; Whitegate; Monkstown-Passage West; Crosshaven; Ringaskiddy; Glounthaune; Glanmire and Midleton
December 2006	Fluvial	Sullane River and Lower lee	Baile Mhic Íre and Carrigrohane Road

Study area

The River Lee is one of the largest rivers in southwest Ireland with a total catchment area covering approximately 2000 sq km. The catchment is defined by the land area drained by the River Lee, its tributaries and Cork Harbour.

The River Lee rises in the mountains to the west of Cork and flows into Cork Harbour. The main tributaries of the River Lee upstream of Cork City include the Sullane River, the River Laney, the Dripsey River, the River Bride and the Shournagh River. The River Lee is partly controlled by the Carrigadrohid and Inishcarra hydro-electric dams owned by the ESB.

From Cork City to Cork Harbour, the river is used for navigation, its channel is dredged and the river banks include extensive quay walls. Cork Harbour also receives freshwater from a number of other rivers including the Glashaboy River, the Owenacurra River and the Owenboy River.

Objectives

The objectives of the Lee Catchment Flood Risk Assessment and Management Study are to:

Assess the flood risk to the catchment as a whole with particular focus on urban areas.
Identify probable future land use and climate changes that could increase the risk of flooding.
Carry out an environmental study, known as a Strategic Environmental Assessment (SEA), to ensure that environmental issues and opportunities for enhancement are fully considered as part of the study.
Consider potential options to manage the flood risk including both structural and non-structural measures.
Develop an economically, socially and environmentally appropriate long-term strategy (a Flood Risk Management Plan) for managing the risk to help ensure the safety and sustainability of communities in the Lee Catchment.