Glenasmole restoration plan will use nature to boost water quality and cut Dodder flood risk

Acquisition of 2,000-hectare site from Nama enables river-catchment conservation approach for first time

A biodiversity project in Wicklow Mountains National Park will see the restoration of 2,000 hectares of bogland, improve water quality for much of Dublin and use nature to reduce flood risk along the city’s Dodder river.

The area, previously owned by a developer, was acquired by the State from Nama in 2016. The project, led by the National Parks & Wildlife Service (NPWS), is the first of its kind to take a river catchment-scale approach to habitat restoration.

Announced on Monday at the Dodder’s source, it will focus on a site at Glenasmole Valley, some 6km from Tallaght, and will extend Wicklow Mountains National Park into the Dublin Mountains area.

Using a suite of land management techniques – including extensive native woodland planting in deep gullies, blanket bog rehabilitation to restore heather, and vegetation management – it aims to increase biodiversity while also providing measurable benefits such as increased carbon storage, reduction in soil erosion and improved water quality. The site has been actively farmed for generations within the national park, which is also a special area of conservation.


The works, announced by Minister for the Environment and Climate Eamon Ryan and Minister of State for Heritage Malcolm Noonan to coincide with International Day for Biological Diversity, will provide important “ecosystem services” to the wider catchment, specifically flood risk alleviation and water quality improvements for the Dodder and Dublin water supply at Bohernabreena reservoir.

“It’s fantastic to see the NPWS leading on this ambitious and innovative catchment-based biodiversity restoration project, and working closely with local farmers to deliver results – collaboration is key in ensuring meaningful biodiversity action,” Mr Noonan said.

The project will have benefits for rural communities at the top of the catchment and those living downstream in the city, he said. It is hoped the approach to habitat management “can act as an exemplar to the wide-ranging benefits of habitat restoration and ecological engineering” elsewhere, he added.

“As a Dublin TD, this is a particularly special project... as it combines restoration of nature with climate action and means real, tangible benefits for people – so nature and people both win here,” Mr Ryan said.

“Bog restoration and native tree planting will not only help wildlife and reduce emissions, it will ensure better water quality for the people of Dublin and help to mitigate flooding, which is a significant issue for people living along the Dodder – which flows all the way from this valley to the city centre,” he added.

This was a very good example of farming working with nature, Mr Ryan said, looking down at the site close to the Dodder source. “We got it from Nama at a good price... It’s a really good day to see the NPWS leading in this way.”

Local farmers will be involved in active conservation of the area, and are already participating in the sustainable uplands agri-environment scheme (Suas) project, according to conservation officer Damian Clarke, who oversees the national park. Improvements in habitat while increasing biodiversity will also offer improved grazing and shade for grazing animals on site, thereby delivering benefits for both wildlife and livestock in coming decades, he said.

Some 60,000 native Irish trees (including birch, rowan, holly, hazel and oak) are to be planted in three gullies with brooks that combine to form the Dodder – totalling 33km of river. The trees will soak up moisture and slow river speed.

Further downstream, this will reduce the need for “massive, concrete-dominated flood protection and culverting on the Dodder”, Mr Ryan said.

The trees are expected to provide enclosures that will enhance smaller bird species including grouse and in turn attract larger predators such as falcons and merlin.

The project will coincide with greater efforts to curb illegal dumping in the area along with antisocial behaviour – notably the burning-out of cars.

Ireland’s nature and wildlife take centre stage with more than 150 events scheduled across the country for National Biodiversity Week, which runs until May 28th.

The annual 10-day celebration of nature and wildlife offers a variety of free events. Organised by the Irish Environmental Network and funded by the NPWS, it will provide opportunities for the public to connect with nature and learn from local experts and groups actively working to protect Ireland’s natural heritage.

Kevin O'Sullivan

Kevin O'Sullivan

Kevin O'Sullivan is Environment and Science Editor and former editor of The Irish Times