North Slob channel, County Wexford

Formerly an area of mud flat and salt marsh, reclaimed in the mid 1800s by construction of a sea wall. A broad, semicircular channel runs through polder grasslands and crops, covering a total area of  approximately 5ha. The area is below high tide level and there is extensive landward seepage of seawater with seepage streams. Mixed seawater and freshwater from streams and drainage ditches is pumped out and the water level is more or less constant. A salinity gradient from about 4‰ in the west to between 20 and 30‰ in the Raven (Curracloe). Channel exists throughout the year.

South Slob Channel, County Wexford

Formerly a creek system in mudflats, reclaimed in mid 1800’s by construction of a sea wall. The network of creeks joining the large Coal Channel runs through an area of polders and salt marsh. Substrate near the sea wall muddy sand – sandy mud. Brackish conditions are probably confined to the part of the Coal Channel near the sea wall where landward seepage of seawater occurs, giving a salinity of 2-5‰. Elsewhere water is probably fresh. Excess water is pumped out into Wexford harbour by way of an artificial perimeter canal.

Lady’s Island Lake, County Wexford

A large (350ha) natural sedimentary percolating lagoon, separated from the sea by a sand and gravel barrier and dunes. Substrate grades from soft sandy mud in the north to coarse sandy gravel near the barrier and there are rocks in the southeast. Surrounding land is flat with arable and pasture fields and rough land with rocks. Freshwater enters by a few small streams and leaves by percolation through the barrier. The water level rises in winter flooding farmland and a pilgrimage path and the barrier is usually breached in spring. The lake then becomes tidal until natural closure in 2 weeks – 6 months. Seawater also enters by seepage and overwash of the breach bar. Salinity fluctuates widely according to season and the extent of tidal flow. In October 1996, 4-15‰ was measured at the north end, 23-26‰  near the barrier and 6-10‰ in an isolated pool.

Tacumshin Lake, County Wexford

Large (430ha) natural sedimentary lagoon with a sand/shingle barrier. In total area this is the largest Irish lagoon but is currently drained and partly dry in summer. A natural outlet has existed intermittently but seals naturally. The substrate is soft sandy mud with gravel near the barrier. Surrounding land is flat and consists of arable fields and pasture. Freshwater enters by several small streams and leaves by the outlet pipes and by seaward percolation through the barrier. Washover occurs in the western sector. Much of the lake bed was exposed during the summer of 1996 following installation of pipes, but water was present to 1m depth by October. Salinity at this time was 8-19‰ on the eastern shore and 3-18‰ in artificial channels near the barrier. Water levels have been monitored recently in an attempt to establish optimum acceptable levels in order to preserve its conservation value.

Ballyteige Channels, Wexford

Ballyteige drainage channels are situated on the south coast of Wexford, 1 km to the west of Kilmore Quay. The drainage channels are artificial and were excavated to drain a lagoon and saltmarsh which were isolated behind an extensive dune system to the south and a sea wall to the west, constructed across the Cull Inlet in the mid 19th Century.  Seawater enters by percolation through the dunes along the southern shore and apparently by leakage of the sluice on the Cull at high tide. It is also possible that seawater enters from the tidal river that runs from Duncormick to Bridgetown. Area of water about 5 ha., length of channels 3.2 km., maximum depth 3m.

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