The River Dodder is one of Dublin’s best known and most important rivers. It flows from Kippure Mountain through bogland, light forest and agricultural land before entering urban Dublin. The Dodder collects rainwater from a 12,081-hectare (120.8km2) catchment which covers three main authorities namely Dublin City Council (DCC), Dun Laoghaire-Rathdown County Council (DLRCC) and South Dublin County Council (SDCC) and discharges to the Liffey Estuary.
The River Dodder’s catchment stretches from Ringsend in Dublin City, west as far as Tallaght and southwest as far as Kippure in the Dublin Mountains. It rises above Glenasmole and in its upper reaches it forms a reservoir system which is an integral part of the water supply to Dublin. It flows down through the suburban areas of Tallaght and Rathfarnham and through the city areas of Donnybrook and Ballsbridge before discharging into the Liffey Estuary at Ringsend. The lower section of the river is tidal up to the weir upstream of Ballsbridge.
The upper portion of the catchment from the source to Old Bawn in Tallaght includes the two Bohernabreena Reservoirs (Upper and Lower) and their spillways. This section is mainly rural while the lower catchment is already heavily developed with residential and industrial land uses.
There are five main tributaries whose sub-catchments drain into the River Dodder; the Tallaght stream, the Owendoher, the Whitechurch, the Little Dargle and Dundrum Slang, all which are heavily urbanised streams. The surrounding parklands are an extremely important amenity to Dublin and the river is widely used by fishermen and a variety of sporting and recreational interests over its 27 km long course.
The River Dodder has history of flooding and is known as a “flashy” river with a quick response to rainstorms. This is due to its source being in the Dublin mountains which provides it with a steep gradient and periods of high rainfall. In the last century it has overflowed its banks on numerous occasions causing damage to adjacent properties. A number of areas have experienced river and/or tidal flooding within the Dodder catchment. These flooding problems mainly cause damage to public roads and properties also flooding parkland in the urban areas of the Dodder catchment and result from both fluvial (river) and tidal sources.
DCC have several river levl monitors and rain gauges along and near to the River Dodder. The warning levels in increasing severity are Green, Yellow, Orange and red respectively. At the Yellow warning level a notice is sent to the duty engineer to investigate further.
Dublin City Council has commissioned ByrneLooby (BL) to develop and implement a flood alleviation scheme (FAS) for the River Dodder from Clonskeagh Road Bridge to Orwell Road Bridge including flood defence works on the Little Dargle stream at Braemor Road-Woodside Drive south-eastern junction. This project is known as the River Dodder Flood Alleviation Scheme Phase 3.