Thames Water, in partnership with Natural England, the Environment Agency, the Lee Valley Regional Park Authority and a number of local authorities, are investigating opportunities to increase public access and recreational use of the Walthamstow Reservoirs. This complex of ten reservoirs forms part of the Lee Valley Special Protection Area (SPA) which was classified on the basis of its populations of wintering bittern, gadwall and shoveler. The reservoirs have also been designated a Site of Special Scientific Interest (SSSI) due to the presence of a nationally important heronry, and large numbers of breeding, moulting and wintering wildfowl.
BSG Ecology’s role in the project
BSG Ecology was appointed to lead the technical ornithological work at Walthamstow because of our ornithological capability and detailed understanding of the legislative context of the work required. Under the Conservation of Habitats and Species Regulations (2010) the proposed access strategy, which will manage increased recreational use, must establish what the likely effects on SPA interest are in order to inform the Appropriate Assessment process. Our approach has been to design a bespoke survey program to provide the information necessary to determine whether a significant effect is likely to occur.
Bird Survey Work Undertaken
The survey involved mapping all wintering waterfowl species using a gridded system extending across the reservoir complex. Surveys were undertaken on a twice monthly basis during the winters of 2010/11 and 2011/12. Care was taken to vary the timing of each visit and the order in which reservoirs were visited; and to ensure that data were collected in a representative range of weather conditions. In addition, detailed observations were made about the reactions of individual species and mixed flocks of birds to baseline levels of disturbance, particularly: maintenance works; the presence of fishermen, and intermittent relatively loud noises (such as passing trains and overflying helicopters).
The data generated by the survey work was imported into GIS, allowing ‘heat maps’ for all key species to be generated on both a single visit and full winter basis. This has established clear patterns of seasonal occurrence and distribution of key species within the complex of water-bodies, as well as providing very useful information on changes in bird numbers and the nature of use of the reservoirs in response to extreme weather and varying types of recreational disturbance. The work is ongoing and the approach and outputs have been praised by Natural England.