The health of the River Irwell and its catchment continues to steadily improve from the later years of the 20th Century. Industrial demands on this precious resource have reduced, pollution legislation has evolved and enforced, and a wider shared understanding and duty of care of our environment has become a way of life for an increasing number of businesses and members of the public. It is important to acknowledge that many agencies, organisations, groups and individuals have contributed to the changes we have seen. However, the recovery of the River Irwell is still in an infancy period, failing many EU and national environmental health index standards. The scale and complexity of the conservation and restoration of the catchment is too great for any one organisation. Working in partnership with regulators and public, private and voluntary sectors combines specialist knowledge, skills and services, to overcome many issues, achieve common aims and objectives, and ensure the sustainability of efforts for future generations.

Some of the main issues of our catchment are described below:

Holly Murray, surveying Irwell stream life while on work placement from Cambridge University
Holly Murray, surveying Irwell stream life while on work placement from Cambridge University

Water quality

Many species of aquatic micro-organisms (invertebrates), plants and animals which are key to indicating the good health of river environments are absent or only present in low population numbers in isolated areas in the Irwell catchment. This is because the water quality is poor, failing to provide the conditions necessary for these species to exist and thrive, and poses a health risk for other river users (recreation etc…). Some reasons for poor water quality include:

  • Soil contamination from previous mining and industrial activity
  • Waste Water Treatment (sewage) outfall
  • Misconnections in the sewerage network
  • Road runoff
  • Illegal tipping/disposal of toxic substances

Landscape quality

Hall 'th 'wood
Hall I’ th’ Wood weir, Eagley Brook

The river landscape was heavily modified during the industrial revolution, causing environmental impacts on the watercourses and also a loss of biodiversity from the terrestrial/riparian habitats that adjoin them. Some structures, such as working properties and transport infrastructure are here to stay, the rivers course now defined and constrained by this landscape. However, many structures such as walls, weirs and derelict mills are now redundant and in poor condition, crumbling and collapsing, serving no meaningful purpose/service and impeding the recovery of the environment. Some have local and national historical and cultural importance and must be treated sympathetically, while opportunities for removal or modification of many structures to aid river restoration remain significant in number.

  •  Weirs impede fish migration
  • Walls and weirs fragment and isolate habitats
  • Canalised watercourses have lost connectivity with their natural floodplain
  • Walls increase demands on flood management schemes
  • Crumbling structures pose a risk to human health
  • The river acquires coarse un-natural sediment from crumbling structures
  • Walls and weirs impede the geomorphological recovery of the rivers form
  • Prevent bankside vegetation establishing
  • Reduce public access to the river


Other environmental and social factors

Bigger Goat
“We’re going to need a bigger goat”. Our friend Billy, eating his way through a Giant Hogweed stand.

Many pressures and factors shape the Irwell catchment landscape and the health of the environment. While some environmental issues may seem insignificant in isolation, as contributors they can determine the tipping point between the success and failure of conservation and restoration initiatives. Other pressures and factors shaping the Irwell catchment environmentally, socially and economically include:

  • The catchment supports 2 million people, putting strain on our water resources (water supply, waste water treatment, abstraction, recreation)
  • The population is anticipated to increase
  • New growth in development is targeted for this area
  • Urban runoff has implications for water quality and flooding
  • Invasive plant and animal species threaten native species
  • Litter is abundant
  • Limited or dangerous access to the riverside
  • Climate change
  • Local industry pressures to meet legislation in hard economic times
  • Awareness needs to be raised

See what we’re doing to tackle some of the above issues.