Standing at the confluence of the River Irwell and River Croal the site was used around 1850-70 as a tip for toxic alkaline waste from the production of sodium carbonate (soda ash) by the Leblanc process. The waste, known as "galligu", was a blue sludge (from reduced iron compounds) dominated by calcium sulphide and smelling of bad eggs. The surface of the waste has since weathered down to calcium carbonate, and calcicolous vegetation has colonised the site. As natural limestone grassland does not occur in Greater Manchester, many of the species found are rare in the county.
There are a number of different habitats on the site, the creation of which were dependent upon: the type of waste deposited, the pattern of deposition and the nature of the underlying substrate:
- Open, species rich, calcicolous grassland.
- Fescue grassland with salix scrub.
- Wet areas with rushes, marsh plants and salix scrub
- neutral grasslands.
- Acid grasslands.
- "Nob End citation" (PDF). Sites of Special Scientific Interest. Natural England.
- "Map of Nob End". Sites of Special Scientific Interest. Natural England.
- "Nob End". Local Nature Reserves. Natural England.
- "Map of Nob End". Local Nature Reserves. Natural England.
- Shaw, PJA; Halton, W (1998). "Classic sites: Nob End". British Wildlife Magazine. 10: 13–17.
- Anon. "File SD 70/2: Nob End" (PDF). Retrieved 18 February 2012.
- Richardson, Derek. "Grasslands" (PDF). Habitat Action Plan 2009. Greater Manchester Biodiversity Project. Retrieved 18 February 2012.
- Pennine Waterways
- Gemmell, R.P.; Crombie S.A. "Management of waste tips for enhancement of landscape quality". Landscape Research. Taylor & Francis Group. 1 (1): 10–11. doi:10.1080/01426397508705789.