Irwell Valley

[1] The glaciers of the Pleistocene epoch further shaped the landscape and then retreated, leaving behind deposits of sand, pebbles and boulder clay that formed the fluvioglacial ridges of the Irwell Valley.

The waste from the industries along the Irwell polluted the river so heavily that by the 1850 it was virtually devoid of wildlife, however, since the late 19th century many attempts have made to improve the quality of the water.

This body ordered local authorities to provide sewage treatment facilities, and industrial concerns were told to use the best practical means of preventing pollution.

Caustic waste from the Leblanc process was dumped on at least two sites - Nob End, to the south of Bolton and Lower Hinds in Bury.

The waste on both sites has since weathered-down to calcium carbonate and has provided an ideal environment for a number of nationally rare calcicolous plants, unique in what is predominantly an area of acidic soil.