Eutrophic Urban Pools

2.1 Water Quality

Chemical and oxygen content of the water is important. High levels of phosphates and/or nitrates can cause algae blooms (including blue green algae, some of which are toxic). Low oxygen levels can cause fish deaths.

Silting up also affects the water quality by holding much of the nutrients within the system. De-silting sometimes has a positive effect on water quality as well as keeping a range of micro habitats in existence at the base of the pond. These micro habitats form refuges for invertebrates which feed on the algae and are also a necessary habitat for species such as crayfish.

High turbidity prevents plants from re-establishing due to lack of light for growth.

Run-off from roads or other civil engineering works can have an adverse affect the quality and quantity of ground water and thus on pools.

2.2 Aquatic Plants

Plant life contributes to oxygen levels in water and provide shelter for animals and a base for many aquatic food chains. Problems occur if the plants are over-grazed by waterfowl or uprooted by fish such as carp.

2.3 Invertebrates

Invertebrates are an integral part of the food web. Carnivores (leech, dragonfly larvae), herbivores (water snails), detritivores (water slaters), and filter feeders (such as Daphnia) all help to make this a potentially rich habitat.

Invertebrates such as Daphnia are an integral part of the aquatic food web. They are not only eaten by many other aquatic creatures but themselves eat algae, thus helping to maintain a clear water environment. Daphnia are found in large numbers sheltering under floating aquatics such as water-lilies.

2.4 Fish

Carp fishing is a popular sport, but carp can uproot plants whilst feeding. Bream can increase the turbidity of the water (they also tend to be bottom feeders) by causing re-suspension of sediments. This increases the amount of nutrients released into the water. Young bream feed on large amounts of Daphnia, reduction of which can also lead to reduced water clarity. It is also clear that bio-manipulation of fish stocks occurs unofficially.

2.5 Waterfowl

Birds such as Canada geese have increased dramatically over recent years. They have inefficient digestive systems and large amounts of nutrients, particularly phosphates, enter the water through their droppings. Food left for them by humans also often enters the water directly, rots, and reduces oxygen levels. Canada geese also compete with native wildfowl for nest sites.

The feeding of wildfowl artificially increases the number of birds to a point where they destroy their own habitat. In addition their health can be at risk through inappropriate food stuff as well as from material rotting in the water.

2.6 Humans

Paddling, swimming and boating also have an affect, albeit a minor one, on sediments by stirring them back into suspension and contributing to further enrichment and the further growth of algae. The excessive feeding of wildfowl also exacerbates any existing problems with brown rats thereby introducing health risks such as that of Weil's Disease.

The trampling of pool edges can also increase erosion.

3.1 Legal Status

Most urban pools are owned by Local Authorities or other statutory bodies. Many are within formal parks or public open spaces and are suffering from the general malaise affecting such areas. Most of these places have their own Bye Laws, often not stringently applied.

3.2 Management, Research and Guidance

Under the Environment Act, 1995, the Environment Agency have a general duty to promote the conservation of aquatic flora and fauna, so far as they consider it desirable.

Local Authorities and British Waterways also have statutory duties towards nature conservation and some eutrophic urban pools are within SSSIS, SINCS and SLINCS.

All of these bodies have some responsibility for pollution control.

Closer co-operation has been perceived recently between angling groups, nature conservation groups and land (and water) managers. This must be encouraged and built upon.

The Environment Agency, English Nature, Wildfowl and Wetlands Trust, Wandsworth Borough Council and the Game Conservancy have carried out research and published much research and advisory material.

ACTION	Potential Deliverers		YEARS							Meets Objective No.
	Lead	Partner	2001	2002	2003	2004	2005	2006	2011
5.1 Policy and legislation
Seek the inclusion of effective measures which protect eutrophic urban pools in the preparation of Unitary Development Plans, Local Environment Agency Plans and/or other policy documents.	LAs, EA	WT / EN	As UDPs, LEAPs and other policy documents are prepared.							1, 5
Ensure that appropriate policy is included in all Parks and Greenspace Reviews	LAs	WT								1,5
Produce Best Practice Guidance Document	WT, LAs	EA, STW								4
Set up a "Still Water Managment Group".	WT, LAs	Angling Clubs								3
5.2 Site and species afeguard and management
Identify sites of particular value for biodiversity	WT	LO								1,5
Identify sites in need of urgent management and introduce managment and monitoring.	WT	LO, LAs, EA								1,5,6
Identify presence of important species	WT	LO								5
Draw up management plans where appropriate	WT	EA, LAs, LO								5
Identify funding sources for pool management	WT	EA, LAs								4
5.3 Advisory
Draw up best practice guidelines and promote these to landowners and pool managers	WT									5
5.4 Future research and monitoring
Continue existing Canada goose monitoring	LAs, WMBC	ER, WT								1, 7
Introduce recording methods for fish catches	LO	ER								6
5.5 Communications and publicity
Prepare Advisory Booklet for schools	WT									7
Interpretation at all appropriate pools	LA, EA	WT								7
5.6 Links to other action plans
Canals, garden ponds, gardens, allotments, parks and public open space, rivers and streams

This Biodiversity Action Plan will be implemented over 10 years with a first review after 5 years. A group will be set up to co-ordinate implementation and to report to the Biodiversity Action Plan Steering Group. This group will meet at a minimum on a yearly basis.

Review will be carried out in conjunction with related Habitat and Species Action Plans as appropriate.

Review will consist of measuring achievement of targets. The group will, with the support of the Steering Group, develop and implement appropriate monitoring methods, which will inform the review process.

The Action Plan will be revised and updated in the light of review results and any relevant changes in circumstances and / or additional information which becomes available during the review period.

In line with national guidance, the Steering Group will report to the UK Biodiversity Steering Group.

ARC and the Game Conservancy - "Wildlife after Gravel".

Wandsworth Borough Council - London Lakes Project.

Biodiversity Action Plan for Birmingham and the Black Country © 2000

Printing of this publication for educational purposes is permitted, provided that copies are not made or distributed for commercial gain, and the title of the publication and its date appear. To copy otherwise, or to republish, requires specific permission from the Steering Group.