WILDLIFE CONSERVATION AND THE ENVIRONMENTAL STRATEGY OF THE BEDFORD GROUP OF INTERNAL DRAINAGE BOARDS
From 2001, the Bedford Group of Internal Drainage Boards comprises three IDBs in the upper reaches of the Great Ouse catchment, largely in Bedfordshire, but also Milton Keynes, small areas in north Oxfordshire, north Buckinghamshire, north Hertfordshire and south-east Cambridgeshire. The Group manages a total of 1147 km of watercourses within its Drainage District, serving an agricultural area of 37736 ha and an urban area of 7176 ha.
The Bedford Group aims to reduce the risk from flooding to people and the developed environment by the provision of technically, environmentally and economically sound and sustainable defence measures in accord with local needs and central government policy. In order to achieve this, it employs measures including prioritisation of drainage activities according to flood risk and adjacent land use, and a commitment to development control issues in order to cater for the extensive development pressures in and adjoining the Drainage District.
The Group intends to play a positive role in fulfilling its statutory and other responsibilities for nature conservation. Policies include:
- seeking to avoid, wherever possible, damage to the natural environment;
- fully complying with legislation protecting species;
- aiming to ensure that there is no net loss to habitats and species covered by Biodiversity Action Plans;
- seeking opportunities to enhance the aquatic environment;
- ensuring that Water Level Management Plans are completed, implemented as appropriate and reviewed in accordance with Defra targets;
- co-operating with other bodies to make an input into the development of Local Environment Agency Plans and Biodiversity Action Plans;
- co-operating in the development of a Biological Records Database for Bedfordshire.
To help implement these policies, the Bedford Group has produced a Conservation Handbook which provides the background information needed to enable it to carry out its duties in an environmentally sensitive manner. This includes information on current legislation, relevant contacts in other organisations, arrangements for consultation and survey, and locations of protected sites and species, all of which need to be considered when planning works. Importantly it also provides a best practice guide for watercourse management operations and identifies enhancement opportunities. The Group gratefully acknowledges the kind assistance of the Environment Agency, English Nature and Bedfordshire County Council in reviewing the Handbook. It is intended to supplement the use of this Handbook by regular training of both ground staff and supervisors. This leaflet summarises the principal points.
The intention of the Bedford Group is to ensure that the watercourses for which it is responsible are as morphologically and biologically diverse as is consistent with maintaining appropriate flood protection. Particular care will be taken within statutorily protected sites such as Flitwick Moor, Fancott Meadows and Tebworth Marsh Sites of Special Scientific Interest (SSSI) and also Wildlife Trust Reserves. Biodiversity Action Plan habitats and species and statutorily protected species will be given special attention when considering future works.
Attention will be given to:
- Retaining the features of importance for wildlife.
- Providing continuity of habitat or features along a watercourse.
- Compensating for any losses during periods of maintenance as far as is possible.
- Providing conditions for enhancement either by extending existing high quality habitat or by creating new habitats.
Features of importance include banks with a mix of taller and shorter vegetation, steep earth banks, shelves at water level, stands of marginal vegetation such as reeds, in-channel vegetation, riffles and pools and gravel bars and shoals. Adjacent features such as old trees, tall hedge-lines and bushes are also important.
The Bedford Group operates a rolling programme of works. This will be sent to the Environment Agency and also to English Nature where a SSSI is concerned or where it is believed that protected or priority species may be present. The programme will be sent to the relevant County Ecologist who will then disseminate it to the other relevant conservation interests. In Milton Keynes, the programme will be sent to the Milton Keynes Parks Trust.
No works will be carried out on or adjacent to SSSIs without prior consultation with English Nature, on or adjacent to Wildlife Trust reserves without prior consultation with the relevant Wildlife Trust or on or adjacent to County Wildlife Sites or Local Nature Reserves without prior consultation with the County Ecologist unless they are undertaken as part of emergency operations.
Surveys at different levels of detail may be needed prior to work. Data obtained from the consultation process, from the Group’s database or from the supervisor’s walk-over will identify what, if any, surveys are required. If it is possible that protected species could be affected by proposed works then an ecological assessment will be made by appropriately licensed and trained personnel. River Corridor Surveys will be carried out on watercourses with a work return period of 2-6 years where it is intended to modify any long-running management programme or, as a one-off, undertake any work within the channel with the exception of hand clearance. They will also be undertaken on watercourses with a work return period of more than 6 years where any work other than hand work will be undertaken within the channel.
Timing of works will be, as far as possible, to benefit the ecological interest of the watercourse and adjacent land. For example, the bird breeding season from mid-March to mid-July will be avoided wherever possible and woody vegetation cutting will normally be undertaken in winter as this provides the best chance of regeneration. However, the Bedford Group operates throughout the year and it is not always able to gain access to land at the optimum time both for conservation purposes and to have watercourses in a suitable condition to minimise flood risk during the September to May maximum risk period. In general, spring and summer works will be confined to watercourses which have least ecological value.
Bank vegetation maintenance may be required to provide a passage for floodwater, prevent succession from grass to trees and shrubs, increase the root mat (thus reducing erosion risk) and increase amenity use. Wherever the watercourse width and the standard of service demanded allow, cutting will be restricted to one bank only. A fringe at the bottom of the bank will provide a continuum between terrestrial and aquatic communities. Continuity of less frequently managed habitat is important but grassland will not be allowed to become invaded by scrub where conservation interest is high or it would affect flood water conveyance and access for channel maintenance. The bird breeding season and the seed setting season mid-March – mid-July will be avoided as far as possible and grass banks will be mown earlier only if ground-nesting birds are not present. Piles of cut vegetation may be retained as they are important for mammals and reptiles.
Tree maintenance may be necessary to provide access to a channel for maintenance work, to remove the risk of trees falling into the channel or to remove low-growing limbs that accumulate floating wrack and thus reduce conveyance. The Group’s practice is to retain old trees and manage as few trees as possible, as lightly as possible. Felling is the last resort. When gaining access for channel works it may be possible to leave a ‘tunnel’ within overhanging trees. If material must be burned it will be done away from important or vulnerable areas. Where acceptable, it may be heaped above flood levels eg to form otter holts or make “habitat piles” for invertebrates and nesting birds. Pollarding may be undertaken in appropriate areas between November and March following assessment for presence of bats. Where access is needed over hedges, then coppicing may be undertaken. A rotation of coppicing along a river helps maintain various stages of tree growth and refuge and cover for wildlife.
In-channel weed maintenance is undertaken to increase conveyance, reduce water levels, prevent silt deposition and protect the functioning of structures which may otherwise become clogged. Where possible, weed will be cut in patches so as to retain areas for re-colonisation or along the centre of the channel only, leaving the margins which concentrates flow into a central channel. Where trees provide shade so that in-channel growth is inhibited, they will normally be retained. Leaving an uncut base to the bed of the channel is important and a further 0.25m wide on both banks is desirable where the watercourse is wide enough to allow this.
De-silting operations are most often undertaken, with additional work on the banks only where and when required e.g. where slips have occurred. The need for works is entirely related to flood defence needs so as to maintain capacity, stabilize banks and to maintain conveyance. Reforming (removing firm material) and re-grading (bed and banks) requires a site-specific approach, always involving an ecologist, often involving River Corridor Survey and sometimes involving an Environmental Impact Assessment. Protection of existing ecological interest is paramount in de-silting operations and riffles, areas of cobbles and gravels will be left untouched or replaced. One working bank only will normally be used, being chosen for ease of access, sensitivity of vegetation present, adjacent land use including presence of crops and the need to minimise works along the channel. Variation in the long-section as well as the cross-section of a watercourse will be an objective. Enhancements will be considered where possible and working undertaken wherever possible to mimic natural fluvial processes. Spoil may be incorporated into adjacent land via thin spreading, usually within 2-10m of the watercourse. On pasture, spoil may be placed into a trench and then covered with the topsoil.
A conservation database has been established by the Bedford Group, compatible with those for its other activities. Data is entered on a GIS system and this includes statutorily protected sites, other sites of conservation importance, Biodiversity Action Plan species, protected species and priority habitats. It is intended that information will be exchanged with other data bases such as that being established by Bedfordshire County Council and various Biological Records centres. The Group appreciates data given by English Nature and the River Ivel Project.
Water Level Management Plans have been completed for all hydrologically-sensitive SSSIs within the Drainage District. These are Flitwick Moor, Fancott Woods and Meadows and Tebworth Marsh. The latter two sites were in satisfactory hydrological condition and required the maintenance of the status quo but Flitwick Moor requires technically demanding solutions to deal with the problems of nutrient-rich flood waters entering typically low-nutrient areas. Replacement of structures is required together with in-channel works and creation of a flood storage area. The Plan was written in collaboration with English Nature, Bedfordshire County Council and the Wildlife Trust who are working to acquire land whilst the Group completes the design.
Enhancement works have now been undertaken on a variety of watercourses. For example, pollarding has been undertaken on a tributary of the River Ouzel at Ivinghoe and in-stream flow deflectors have been provided in the River Ivel at Stotfold. Adjacent to the River Ivel, a flood bank has been seeded with flower-rich seed and, at the request of the Wildlife Trust, a pond and scrape have been provided. Creation of a new willow-lined back channel has been created at Padbury, Bucks.
Bio-Diversity Action Plans (BAPs)
Click the links below to view the BAPs for the individual Boards: