Case study:Upper Mun Restoration: Frogshall Wetland Project
Project overview
| Status | In progress |
|---|---|
| Project web site | http://www.norfolkriverstrust.org/trust_project/upper-mun-restoration-northrepps-wetland-project/ |
| Themes | Water quality |
| Country | England |
| Main contact forename | the |
| Main contact surname | RRC |
| Main contact user ID | User:JoshRRC |
| Contact organisation | Norfolk Rivers Trust |
| Contact organisation web site | |
| Partner organisations | |
| Parent multi-site project | |
| This is a parent project encompassing the following projects |
No |
Project summary
The upper River Mun close to Northrepps suffers from chronic pollution. This has reduced the wildlife diversity in the river, and is almost certainly the cause of the periodic death of fish in a downstream lake, Little Broad. Often pollution is invisible, even when quite severe. However, in this case it is plain for the eye to see. Nutrients coming down the stream, predominantly from the Anglian Water sewage treatment works, are causing a condition called eutrophication. This is the extreme growth of plants and algae due to nutrient enrichment. This causes the death of fish and other aquatic organisms in a boom and bust cycle. At the height of algae and plant growth in the spring the water becomes “super-saturated” with oxygen (the oxygen “boom”). As the oxygen tries to force its way out of the water, this causes bubbles to form in blood-vessels of the fish, similar to the condition “the bends” in divers. This causes distress and often death. In the autumn, the algae dies and rots (the oxygen “bust”) and there is now not enough oxygen.
Pollution also has more subtle effects. Elevated levels of nutrients also cause a loss of plant diversity, because dominant “greedy” plants and algae out compete others. A lake (and in some cases rivers) without a diverse plant community is like a rainforest where all but one species of tree are cut down in the sense that this causes a reduction in diversity of all over groups of organisms as well. In short, the upper Mun has a impoverished community of plants and animals due to pollution and this effect is also likely to be passed on down the stream.
However, the Norfolk Rivers Trust are working on plans to reduce the nutrients by routing the effluent from the Sewage Treatment Works through a series of wetlands. This would not be possible without the incredible generosity of the landowner who is prepared to sacrifice land in order to help wildlife and improve water quality. The wetland will remove the nutrients by biological and chemical processes. NRT are taking advice from several universities including University College London, Cranfield and Saint Mary’s University in order to ensure that the project delivers maximum benefits. This project will happen in early October and we are looking forward to seeing if our efforts and those of our outstanding volunteer group in the area can reverse the fate of this damaged little river.
Monitoring surveys and results
Lessons learnt
Image gallery
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Catchment and subcatchment
Site
Project background
Cost for project phases
Reasons for river restoration
Measures
MonitoringHydromorphological quality elements
Biological quality elements
Physico-chemical quality elements
Any other monitoring, e.g. social, economic
Monitoring documents
Additional documents and videos
Additional links and references
Supplementary InformationEdit Supplementary Information
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