Habitat Statement

In their natural state rivers are dynamic systems, continually modifying their form. However in many cases their ability to rejuvenate and create new habitat has been reduced or arrested by flood defence structures and impoundments. Few rivers in the UK have not been physically modified by man and such rivers represent a very valuable resource. Erosion of banks has also been caused by canalization and the removal of tree cover in historic times. Such activities have resulted in changes in the frequency and magnitude of flooding, altering seasonal patterns of flows and hydrograph form. In addition, flow regulation has altered patterns of sediment transport and nutrient exchange in river systems. Any resulting eutrophication can have detrimental effects on floodplain habitat which still retains some connection with the main stream.

The mosaic of features found in rivers and streams supports a diverse range of plants and animals. For example, riffles and pools support aquatic species, and exposed sediments such as shingle beds and sand bars are important for a range of invertebrates, notably ground beetles, spiders and craneflies. Marginal and bankside vegetation support an array of wild flowers and animals. Rivers and streams often provide a wildlife corridor link between fragmented habitats in intensively farmed areas.

The plant and animal assemblages of rivers and streams vary according to their geographical area, underlying geology and water quality. Swiftly-flowing upland, nutrient-poor rivers support a wide range of mosses and liverworts and relatively few species of higher plants. The invertebrate fauna of upland rivers is dominated by stoneflies, mayflies and caddisflies, while fish such as salmon Salmo salar and brown trout Salmo trutta will almost certainly be present. In contrast, lowland nutrient-rich systems are dominated by higher plants, and coarse fish such as chub Leuciscus cephalus, dace Leuciscus leuciscus and roach Rutilus rutilus. Where nutrient levels are artificially raised, the occurrence of algae increases.

The primary threats to rivers and streams are:

• Pollution including eutrophication and acidification.

• Excessive ground water and surface water abstraction.

• Construction of dams and reservoirs.

• Water transfer schemes between rivers.

• Land drainage and flood defence works which if not sensitively carried out, can reduce stream habitat and isolate streams from their floodplains.

• Inappropriate bank management, including overgrazing.

• Introduction of invasive plant and animal species.

• Industrial, housing and hydro-electric power scheme development within the floodplain.

In carrying out their functions the NRA, Water Companies, Internal Drainage Boards (IDBs) and Local Authorities in England and Wales have a statutory duty to further conservation where consistent with purposes of enactments relating to their functions. These are set out in the Water Resources Act 1991, and the Land Drainage Act 1991. River Purification Boards (RPBs) in Scotland do not have the same duties. Both the NRA and RPBs have statutory responsibilities for pollution control.

The duty to further conservation applies to the water management functions of the Environment Agency for England and Wales from April 1996, while the pollution control functions of this Agency will have a duty to have regard to the desirability of conserving and enhancing features of special interest. The establishment of the Scottish Environment Protection Agency (SEPA) and the new water authorities in Scotland will strengthen conservation duties compared to the predecessor RPBs.

The Water Act (NI) 1972 is currently under review. In Northern Ireland responsibility for water quality, water supply and drainage resides with the Environment Service of DoE(NI), Water Service DoE(NI) and DANI respectively. Environmental Assessment legislation requires all works with the potential to have a significant effect upon the environment to be subject to formal impact assessment. In the context of river engineering works this includes new, improvement and heavy maintenance works. The Environmental Statement on the extent of the impacts is open to public scrutiny.

Ministers can direct IDBs in England and Wales in order to prevent serious damage to conservation sites of national and international importance. Local Authorities in England and Wales have a statutory duty to further conservation when carrying out improvement works, so far as is consistent with the purposes of the Land Drainage Act 1991.

In Northern Ireland there are unlikely to be any new works e.g. drainage schemes on rural watercourses and Environmental Impact Assessment Regulations are in place to deal with situations where maintenance works are liable to have a significant effect on the environment. In England, some 27 river SSSIs will be notified by March 1998, representing 3% of main river length. A programme for SSSI notification of rivers in Scotland is also being pressed forward and in Wales further notification of rivers as SSSI is under review. The NRA and NE have agreed through a 'Memorandum of Understanding' to produce joint conservation strategies for SSSIs.

Under the EC Habitats Directive the UK Government is still considering areas which might qualify as SACs for a number of riverine interests listed on Annex II.

A number of agricultural support schemes are in place which aim to benefit watercourses. These include some ESA prescriptions, the Countryside Stewardship Scheme (aimed at creating buffer strips), the Habitat Scheme Water Fringe Option (aimed at buffer streams upstream of SSSIs), and the Habitat Improvement Scheme in Northern Ireland which is relevant to some 'scheduled' waters.

Management plans are being prepared by the NRA for 163 river catchments in England and Wales. Each plan will be the subject of a public consultation exercise which is due to be completed in 1998..MAFF guidance on Water Level Management Plans has been prepared and a timetable issued for their production for relevant SSSIs in England and Wales which includes some rivers and streams.

In February 1995, the Secretary of State for the Environment announced a pilot scheme regarding Statutory Water Quality Objectives, which includes a small number of rivers. Water Quality standards that maintain the special conservation interest of streams and rivers, with particular emphasis on combating artificial nutrient enrichment, should be widely implemented. In Northern Ireland, Catchment Water Quality Management Strategies are being developed.

A small number of rivers, mainly in England, have been identified as targets for phosphate stripping from their sewage effluent, and two demonstration river restoration projects are currently in operation, with funding from NRA, NE, EC LIFE and others.

Flood defence works should be carried out in an environmentally sympathetic way, enhancing degraded rivers wherever the opportunity arises. Technical guidance for environmentally-sensitive flood defence works is contained in The New Rivers and Wildlife Handbook, published jointly by the NRA, RSPB and the Wildlife Trusts in 1994. Guidance on best practice procedures to be followed by flood defence operating authorities has been issued by MAFF; this guidance aims to ensure that environmental issues are afforded due consideration when flood defence works are being planned, designed and implemented.

The Forestry Commission also produced a revised version of the Forest and Water Guidelines in 1993.

The Forestry Authority, NRA and statutory conservation agencies are currently appraising the value of floodplain forests. This appraisal will underpin any future revaluation of the requirements for a forest floodplain creation scheme. The Forestry Commission is also about to start experimental research into the role of coarse woody debris in modifying the physical habitat of upland streams, and also to evaluate the potential of coarse woody debris accumulations for increasing habitat quality and diversity for macro-invertebrates.

A new methodology for assessing the conservation value of rivers at a catchment scale in the UK has been developed. Known as SERCON this computer-based system will increase the rigour and repeatability with which evaluations can be carried out. The NRA is developing a classification of river reaches based on habitat features applicable to the UK as a whole.

Maintain and improve the quality, state and structure of all UK rivers and streams and their associated floodplains.

Restore degraded river and streams taking account of water quality and quantity, structure and hydraulic connection with the floodplain.

Measures to be considered further include:

• Introduce Statutory Water Quality Objectives, especially for phosphates.

• Use Water Level Management Plans and water abstraction licensing procedures for the benefit of wildlife, particularly with respect to key sites.

• Implement integrated catchment management plans.

• Use existing measures, such as the Countryside Stewardship Waterside Landscape option, to support the appropriate management of rivers, streams and their associated habitats, in particular floodplains.

• Reduce acid emissions to reduce damage to rivers and streams from acid rain.

• Review the powers and duties of water management institutions to manage water for nature conservation objectives.

The following LBAPs are working on Rivers and streams:

Originally published in: Biodiversity: The UK Steering Group Report - Volume II: Action Plans (December 1995, Tranche 1, Vol 2, p291)