Mallow Spa, Mallow, Co. Cork.

Survey site description 

The oldest recorded warm spring in Ireland is located at Mallow, Co. Cork. It was discovered in 1724 by Dr. Rogers of Cork and by 1735 was famous around Ireland as a spa and rapidly developed to become a fashionable resort. From about 1775 a decline had begun to set in and the 19th Century marked the demise of the Mallow Spa. The spa and local springs were revisited in the mid 1970's when the local authority decided to examine a modern use for this spring.

The geology of the Mallow area comprises terrestrial Devonian sandstones and shales, together with Carboniferous limestones, sandstones and mudstones (Aldwell, 1996). The source of warm water is considered to be the Dinantian Reef limestone which is 1.2 km thick in the area (Bruck et al., 1986). The fracturing of limestone in this region that resulted from tectonic activity has provided ample opportunity for the upward movement of warm water to the springs.

A number of springs issue at the surface in an area know locally as Spa Glen just outside Mallow town. The largest of these springs is known as Lady's Well (20 m south of the Blackwater River). Warm spring water is contained in a very large well chamber that was constructed at this site. The chamber is elliptical in shape and measures approximately 14 m by 10 m. The chamber was engineered to discharge, via an overflow pipe, to a small channel which flows into the Blackwater River approximately 30 m downstream from the well. The substratum was composed mainly of organic mud overlying a hard limestone bottom. The springs at Mallow were monitored regularly by University College Cork between 1980 and 1982 (Minerex, 1983) It is estimated that Lady's Well had a mean flow of 617 litres/minute (Bruck et al., 1986) and the mean temperature over the three years was 19.5^oC with a range between 17 and 22^oC. The warmest temperature was recorded in summer and the coldest in winter, reflecting ambient air temperatures. Lady's Well is maintained regularly by local authority staff and involves the removal of both submerged and floating vegetation.

Macroinvertebrate / faunal survey 

The warm water spa at Mallow was sampled on all three seasonal surveys. In spring, the water louse Asellus aquaticus dominated the fauna (339 individuals representing 71% of the total sample) but was recorded in reduced numbers in summer (49) and was completely absent from autumn sampling. The molluscs Bithynia sp. were abundant in spring and summer samples but numbers of this species decreased in autumn. Oligochaete worms, which were recorded in low numbers in spring, were common in summer and autumn. Overall, species richness was slightly greater in summer (10 species) than in spring (6 species) and autumn (8 species). Other fauna recorded from the site included small numbers of leeches (very obvious on muddy substrata towards the perimeter of the spa chamber), Ostracoda, the mollusc Lymnaea peregra and the water bugs Micronecta poweri and Gerridae (which were observed in the field but not recorded in the sample) indet.

Physico-chemistry 

Water levels and discharge did not appear to change dramatically over the sample period. Mallow spa exhibited relatively stable and consistent physiochemical parameter measurements with little variation between seasons. Temperature ranged between 19.5 (spring) and 19.9 (summer) which corresponds well with temperatures previously recorded (Minerex, 1983). The pH ranged between 7.27 - 7.46 and conductivity ranged between 400 and 435 µS/cm. Oxygen concentrations remained consistently around 3.5 -3.9 mg/l and 32 - 40% saturation. 

Aquatic macrophyte survey 

Mallow spa is regularly cleared of any aquatic macrophyte community that may develop there. On average, six species were recorded per visit over the survey period. Abundant species were absent from this spring. The only species ranked as 'frequent' was the filamentous algae Cladophora sp. (autumn sample). All other species were recorded as occasional or rare including the algae Spirogyra sp. and Batrachospermum sp., unidentified charophyte species and the vascular plants Alisma plantago (water plantain), Apium nodiflorum (fool's water cress), Lemna minor (pondweed) and Zanichellia palustris (horned pondweed). Water levels in the spring did not fluctuate greatly, however macrophytic and algal growth increased slightly towards autumn.

© Ecological Consultancy Services Ltd 2003