The River Poddle rises in Cookstown, Tallaght and flows north-east through Tymon Park, following a circuitous route through Templeogue, Kimmage, Harold's Cross, Tenters and Temple Bar. The river catchment has become heavily urbanised in recent times, with the watercourse itself becoming regimented, altered and concealed to suit local habitation. The downstream reach of the Poddle in particular is heavily culverted, with the lower 4km flowing almost exclusively beneath the busy South Inner City streets.
There is a long history of flooding from the River Poddle due in no small part to the many historic man-made alterations to the watercourse. Throughout the course of the growth of Dublin City and the development of the Poddle catchment, the conveyance capacity of the river became increasingly constrained and natural areas of floodplain ultimately gradually reduced with increased urbanisation over the years. Due to the constrained nature of the river as it exists today, the Poddle is particularly susceptible to blockages from accumulating debris and fly-tipping at the various structures along its course. In recent times the most significant recorded instances have occurred in 1986, 1993, 2000, 2008 and most recently in 2011. Very significant flooding occurred in October 2011 when up to 90mm of rain was reported to have fallen within a six hour period on the evening of the 24th. The Crumlin and Harold's Cross areas were affected particularly severely during the 2011 event, although flooding was widespread along the Poddle's course.
It is the intention of South Dublin County Council, Dublin City Council and the OPW to prevent reoccurrences of such flood events and the associated disruption and turmoil inflicted on local communities through the provision of flood relief measures to alleviate the risk posed by the River Poddle.