Vartry Catchment

The Vartry rises in Calary Bog under the Great Sugar Loaf mountain in north County Wicklow.

A number of small streams combine to feed the Vartry Reservoirs which are important sources of water for Dublin as well as a high amenity area.

From the reservoir lakes, the river flows east towards Ashford and down through Devil’s Glen. From there it passes the Nun’s Cross Bridge (dating from the 18th century) on through Ashford, under the N11 road and continues eastwards into the estuary at Broad Lough.

Waters in the Vartry catchment:

Vartry River

The headwaters of the River Vartry rise on the east facing slopes between Djouce Mountain and White Hill and are joined by a further tributary which rises in Calary Bog under the Great Sugar Loaf Mountain in north County Wicklow. 

It then flows into the Vartry Upper Reservoir, which is further fed by a number of small local streams and is impounded here by the reservoir dam. A beautifully constructed overflow brings water through the embankment down through a man-made spillway into the Lower Reservoir.  The water is then drawn off to the filter beds below the R764 local road where it is treated for human consumption and enters the mains drinking water supply.

From the reservoir lakes, it flows east towards Ashford under the Annagolan Bridge and down through the Devil’s Glen. From there it passes under the Nun’s Cross Bridge (dating from the 18th century) on through Ashford, under the N11 road and continues eastwards into Broad Lough. 

From here the short run of river through Wicklow Town is known as the Leitrim River and enters the sea in Wicklow Harbour.

In 1861 Parliament passed the Dublin Waterworks Act creating the project to dam the River Vartry in Roundwood to form the Vartry Reservoir. This was completed in 1865 and was the first clean source of water for Dublin, replacing the canal water. There are several references to the Vartry in James Joyce’s Ulysses.

The Vartry River is a suite of contradictions, from a hydro morphological point of view the upper half of the catchment is classified as highly modified due to the impoundment caused by the reservoir whilst the lower half of the catchment is classified as natural.

From a water quality point of view the Vartry has a catchment classification of good and indeed an overall quality rating of good, with some of its upper tributaries gaining high status and in 2016 a fish status of high was recorded by Inland Fisheries Ireland giving the Vartry one of the better overall ecological profiles of the rivers in Wicklow.

Despite these strengths, the Vartry is often pressured by extremely low flows due to the water abstraction in Roundwood and sporadic pollution events which are often compounded by the low flow conditions.

In late June 2012 the Vartry suffered a massive fish kill which affected the entire river below the reservoir in Roundwood. Vast numbers of fish were lost across all species and age classes, luckily invertebrate populations appeared to be minimally affected and an encouraging recovery was evident within 3 years.

Vartry Reservoir

Vartry Reservoir (Irish: Taiscumar Fheartraí) is a reservoir on the Roundwood plateau in north Wicklow. The water is piped from Vartry River to a large open service reservoir in Stillorgan in the southern suburbs of Dublin. The reservoir is operated by Dublin City Council.

The original (lower) reservoir was completed in 1863 and has a capacity of 11.3 billion litres and a maximum depth of 18.3 metres.

A second embankment, 3.5 km upstream, was completed in 1923 to form the upper reservoir. This has a capacity of 5.6 billion litres and a maximum depth of 13.4 metres.

The creation of the reservoir was particularly important in improving living conditions and public health in Dublin city.

Access to clean water improved sanitation and helped reduce outbreaks of cholera, typhus and other diseases associated with contaminated water.

Broad Lough

Broad Lough is the name given to a brackish lake which lies approximately 1 km north of Parnell Bridge in Wicklow Town.

It is included within the boundaries of the The Murrough Wetlands Special Area of Conservation and Special Protection Area (for birds) because of the wetland habitats and species it supports.

Broad Lough is generally classified as a transitional water and was created by a shingle ridge, which divides the River Vartry estuary from the open sea. Broad Lough is tidal and extremely shallow.

The Lough is surrounded by what is known as a coastal salt marsh. The Lough itself and the surrounding marsh both support an enormous diversity of life, both aquatic and terrestrial.

There are a number of important and protected bird species, both resident and transient in the Murrough Wetlands, and the Lough itself is an important breeding ground or juvenile refuge for a number of fish species, notably thick lipped grey mullet.

In 2008 inland fisheries Ireland recorded juvenile Gilthead bream in Broad Lough, a species more common to the Mediterranean.

According to The Life of St. Patrick and His Place in History the place where St. Patrick landed was at Inverdea, the mouth of the River Vartry in County Wicklow.

Besides the Vartry River, several smaller streams feed directly into Broad Lough:

  • Inchanappa

  • Rathnew

  • Wicklow