The reservoirs were constructed between 1883 and 1887 to address Dublin's growing water demand and cholera prevention needs.
The masonry dams are built from local granite sourced directly from the surrounding valley.
Glenasmole Valley is a protected Special Area of Conservation (SAC) due to its unique semi-natural dry grassland and alpine flora.
The reservoirs are a designated Important Bird Area, frequently monitored for nesting raptors.
The project was engineered by the Rathmines and Rathgar Township to improve the quality of water delivered to the city’s south side.
The water travels from the valley to the city via a massive underground conduit system.
Bohernabreena Reservoir Park, located in the scenic Glenasmole Valley, serves as a vital water catchment area for Dublin, fed primarily by the River Dodder. The site features two distinct reservoirs, the Upper and Lower, constructed in the 1880s to provide a reliable water supply for the city. The area is characterized by steep glacial valley slopes, native woodland, and extensive moorland habitats. It functions as a key gateway to the Dublin Mountains Way, offering a network of paths that facilitate both low-level valley walks and challenging mountain hikes. The park is managed by the Dublin Mountains Partnership to balance recreational access with wildlife conservation. The reservoirs remain a functioning element of the regional water infrastructure, resulting in restricted access to the water's edge itself. Visitors encounter a landscape dominated by historic masonry dams and panoramic views of the surrounding Wicklow Mountains. The park is a notable habitat for rare bird species, including the peregrine falcon.
The crest of the embankment between the Upper and Lower reservoirs provides an expansive view of the valley basin.
Wear waterproof hiking boots, as the trails can be muddy and uneven even in summer.
Bring binoculars if you are interested in birdwatching, as the raptor population is significant.
Check the wind conditions, as the valley can be significantly cooler and windier than the city centre.
Attempting to swim or enter the reservoir water, as it is a protected public water supply and strictly prohibited.
Keep dogs on a lead at all times to protect livestock and ground-nesting birds; follow Leave No Trace principles strictly.
