Eutrophic waters


At the turn of the eighteenth century with the increasing industrialisation of Britain an extensive canal system linking towns, cities, quarries and other industrial areas was created. With the decline of industrial usage the narrow canal corridors have widely transformed into lush, diverse wildlife corridors which contain a myriad of species. Canals now form vital wildlife corridors in our sub-region, often passing through intensive farmland or heavily urbanised settings with little open space. In the wider countryside they can significantly contribute to the wildlife habitats through which they pass.

Canal corridors can support rich and varied plant communities including some extremely rare species. Canals host several distinct plant communities: the submerged pond weeds such as hornworts, milfoils and the BAP species grass-wrack pond-weed; emergent plants such as floating water lilies and reed species including reed sweet grass, canary grass, bulrush and branched bur reed which form the emergent fringe. The greatest variety of plant species in found in canals with relatively clear
undisturbed water – usually where there is little or no boat traffic.

The BCS canal action plan will encompasses a number of habitats which fall within and either side of the slow-flowing open-water canal channel. These include the open freshwater habitats of the canal channel itself, marginal waterside habitats of the lower banks and shallows, trees, hedgerows and grasslands of the tow-path verges and built features such as bridges. Where canals are set within cuttings or upon raised embankments, they can become even more substantial features, with much subsidiary grassland and scrub. Canals can also support highly diverse and unusual plant and animal assemblages along the better stretches including creatures such as water voles, white claw-crayfish, otters and kingfishers. Canalside buildings, bridges and tunnels also provide ideal roosting sites for bats. Amphibians and reptiles can include grass-snakes, frogs, toads and newts. Many scarce and declining flowers and insects still occur along several canal corridors.

The aesthetic appeal of canals, their wildlife and heritage make them popular with walkers, fishermen and boat users. They are increasingly the focus of the leisure industry and much new waterside development. These many competing demands and the repair needs of the historic waterway structures need to be managed sensitively to accommodate the needs of local wildlife as well as canal users.

Extract based largely on Warwickshire action plan


WREN funding of up to £250,000 per year is available for Biodiversity Action Plan centric interventions and outcomes is available as per the funding advice page of WREN. This states in summary that the focus of work must always be the conservation improvements of an identified site or sites to benefit one or several BAP priority habitats. For example the recreation of a BAP listed priority habitat, restoration or conservation of a BAP listed habitat or the surveying/monitoring/on site research into a BAP listed habitat at a specified site or sites where this is part of on-site conservation work.

It is the opinion of the author of this page (Terry Cavender) that this funding should be explored in the context of funding towards the reopening of the BCS at the Cosgrove section. However, unlike many other tier 1 councils, NCC does not currently list canals as eutrophic waters in their Biodiversity Action Plans. Both BCC and MK do have canals as eutrophic in these plans. We should initially approach local county councillors to have this potential omission re-mediated. This should be done alongside soliciting support for this piece of work from the neighbouring authorities.


definition is at

University of Essex report is at East Anglia Eutrophic Waters report

MK and Bucks BAP re eutrophic waters is at Bucks and MK BAP re eutrophic waters



Eutrophic Standing Water includes natural systems such as lakes and pools and man-made waters such as ditches, reservoirs, canals, balancing lakes, gravel, clay and chalk pits. BAP Priority Habitat Ponds are defined as permanent and seasonal standing water bodies up to 2ha in extent which meet one or more of the following criteria:

• Habitats of high conservation importance. Ponds that meet criteria under Annex 1 of the Habitats Directive.

• Species of high conservation importance. Ponds supporting Red Data Book species, BAP species, species fully protected under the Wildlife and Countryside Act Schedule 5 and 8, Habitats Directive Annex II species, a Nationally Scarce wetland plant species, or three Nationally Scarce aquatic invertebrate species.

• Exceptional assemblages of key biotic groups: Ponds supporting exceptional populations or numbers of key species. Based on (i) criteria specified in guidelines for the selection of biological SSSIs (currently amphibians and dragonflies only), and (ii) exceptionally rich sites for plants or invertebrates (i.e. supporting ≥30 wetland plant species or ≥50 aquatic macroinvertebrate species).

• Ponds of high ecological quality: Ponds classified in the top PSYM category (“high”) for ecological quality (i.e. having a PSYM score ≥75%). [PSYM (the Predictive SYstem for Multimetrics) is a method for assessing the biological quality of still waters in England and Wales. Plant species and / or invertebrate families are surveyed using a standard method. The PSYM model makes predictions for the site based on environmental data and using a minimally impaired pond dataset. Comparison of the prediction and observed data gives a % score for ponds quality.]

•Buckinghamshire & Milton Keynes Biodiversity Action Plan Eutrophic Standing Water Habitat Action Plan Ponds Habitat Action Plan

• Other important ponds: Individual ponds or groups of ponds with a limited geographic distribution recognised as important because of their age, rarity of type or landscape context e.g. pingos, duneslack ponds, machair ponds.

Such habitats support an enormous variety of plants and animals, from microscopic plants and animals to larger species such as Great Crested Newt, Water Rail and Water Vole. Nutrient status is an important determining factor for the range of species found in eutrophic standing water, as well as depth, edge habitats, bank slope and seasonal water level variation. Current status in the UK

Key associated species include Bewick’s Swan Reed Bunting ,Brown Galingale Reed Warbler, Common Frog Shoveler, Common Toad Smooth Newt, Great Crested Newt Starfruit, Mudwort Water Rail, Mute Swan Water Vole, Otter Freshwater White-clawed Crayfish and Pintail Wigeon