History and Environment

The River Blackwater is one of the largest rivers in Ireland 169 km, draining a major part of Co. Cork and five ranges of mountains, the Boggeragh, Nagle, Ballyhoura, Galtee, and Knockmeldown ranges.
It flows through Kerry, Cork, Limerick, and Waterford and has freshwater stretches as far upstream as Ballydesmond and tidal stretches as far as Youghal Harbour. It enters County Waterford where it flows through Lismore, before abruptly turning south at Cappaquin and finally draining into the Celtic Sea at Youghal Harbour.

The abrupt right turn at Cappaquin is the result of a phenomenon called ‘river capture’ dating back 70 million years. This involved the original river, which flowed through the area, the River Suir, diverting its course eastwards toward Waterford. The old riverbed dried up or remained as a mere trickle. It is possible that either the Glenshelane or Finnisk rivers, which enter the modern Blackwater south of Cappoquin, are remnants of the original Suir.

In any event, by the time the Suir ceased to flow through the Cappoquin area, a major tributary had been coming across Kerry and Cork to meet with it at Cappoquin. As the Suir dried up, this tributary just continued to flow along the old route from Cappoquin to the sea. So, what looks to the eye like one river, the Blackwater, changing course dramatically at Cappoquin was once, in fact, two rivers.

The site of the river is designated a Special Area of Conservation (SAC) selected because of the presence of protected habitats and species listed in Annex I / II of the E.U. Habitats Directive. Habitats on the Blackwater include the estuaries, tidal mudflats and sandflats, old oak woodlands, and alluvial forests.

Oak woodland is well developed on sandstone around Ballinatray, with the acid oak woodland community of Holly, Bilberry, Great Wood-rush, and ferns occurring in one place. Alluvial forests are dominated by alder and willow on flood plains in a range of situations from islands in river channels to low-lying wetlands alongside the channels. A small stand of Yew woodland, a rare habitat in Ireland and Europe, occurs on a limestone ridge at Dromana, near Villierstown. While there are some patches of the wood with a canopy of Yew and some very old trees, non-native and invasive species such as Sycamore, Beech and Douglas Fir dominate.

Species present include the Freshwater Pearl Mussel, White-Clawed Crayfish, Lamprey, Atlantic Salmon, and Otter.
The Freshwater Pearl Mussel is somewhat ironically one of the longest-living invertebrates in existence but also a species that is in serious decline. The typical lifespan is 100 years but can live for over 200 years. It has been revealed to exhibit negligible senescence, meaning they do not have measurable reductions in reproductive capability or functional decline with age. Various factors have led to this decline, one interesting example being the unique composite material of its inner shell known as Nacre or ‘mother of pearl’ which was popular up to the 19th century for use in fashion, the decorative arts, and in the production of musical instruments.

Atlantic salmon are the largest of the salmon. After two years at sea, they average 71 to 76 cm in length and 3.6 to 5.4 kg in weight. But specimens can be much larger. An Atlantic salmon netted in 1960 in a Scottish estuary was recorded as weighing 49.44 kg, while another netted in 1925 in Norway was recorded at 160.65 cm in length.

The colouration of young Atlantic salmon does not resemble their adult stage. While they live in freshwater, they have blue and red spots and as they mature, they take on a silver-blue sheen. When they are adults, the easiest way of identifying them is by the black spots predominantly above the lateral line. When they reproduce, males take on a slight green or red colouration.

Otters are active hunters, chasing prey in the water or searching the beds of rivers, lakes, or the seas. Most species live beside water, but river otters usually enter it only to hunt or travel, otherwise spending much of their time on land to avoid their fur becoming waterlogged. Sea otters are considerably more aquatic and live in the ocean for most of their lives. Otters are playful animals and appear to engage in various behaviors for sheer enjoyment, such as making waterslides and then sliding on them into the water. They may also find and play with small stones. Different species vary in their social structure, with some being largely solitary, while others live in groups – in a few species these groups may be fairly large.