THE RIVER DODDER
The River Dodder is one of the three main rivers in Dublin, Ireland, the others being the Liffey, of which the Dodder is the largest tributary, and the Tolka.
The Dodder rises on the northern slopes of Kippure in the Wicklow Mountains, and is formed from several streams. The headwaters flow from Kippure Ridge, and include, and are often mapped solely as, Tromanallison (Allison's Brook), which is then joined by Mareen's Brook, including the Cataract of the Brown Rowan, and then the combined flow meeting the Cot and Slade Brooks.
In the river's valley at Glenasmole are the two Bohernabreena Reservoirs, a major part of the Dublin water supply system.
The Dodder is 26 kilometres (16 mi) long. It passes the Dublin suburbs of Tallaght and then Firhouse, travels through Rathfarnham, Templeogue, Rathgar, Milltown, Clonskeagh, Donnybrook, and Ballsbridge, and enters the Liffey near Ringsend, along with the Grand Canal, at Grand Canal Dock.
There is a weir just above the bridge at Ballsbridge and the river becomes tidal roughly where the bridge at Lansdowne Road crosses it. The Dodder and the River Tolka are Dublin's second largest rivers, after the Liffey.
The Dodder's main tributaries after Glenasmole, in and prior to which many streams join, are the Jobstown (or Tallaght) Stream, the Owendoher River and its tributary the Whitechurch Stream, the Little Dargle River (with Castle Stream and other tributaries), the Slang or Dundrum River,[the Swan River (or Water), and the small Muckross Stream.
The river floods some surrounding areas from time to time, as it is too short and shallow to hold the volume of water which pours into it from its tributaries during heavy rain. The River Dodder "has a history of flooding and is known as a "flashy" river with a quick response to rainstorms."
A flood on the Dodder in March 1628 claimed the life of Arthur Ussher, Deputy Clerk to the Privy Council of Ireland who was "carried away by the current, nobody being able to succour him, although many persons.. his nearest friends, were by on both sides."
The two greatest Dodder floods before 1986 occurred on 25 August 1905, and on 3 and 4 August 1931. Hurricane Charley (often spelled "Charlie" in Ireland) passed south of the country on 25 August 1986. In 24 hours, 200mm (almost 8 inches) of rain poured down on Kippure Mountain while 100mm fell on Dublin causing heavy river flooding, including the Dodder in many places, and hardship and loss were experienced.
It has long been recognised that the problem of flooding is very difficult to solve, due to the sheer volume of water which pours into the river during periods of heavy rainfall.