A core principle of the approach to mitigating the impact of new residential development on the Thames Basin Heath SPA is the existence of three buffer zones around the SPA, also referred to as ‘zones of influence’. These zones are divided as follows:
- From 0m to 400m
- From 400m to 5km
- From 5km to 7km
The distances are measured as a straight line from the SPA perimeter to the point of access on the curtilage of the dwelling(s).
400m zone: Within this zone it is not considered possible for mitigation measures to protect the integrity of the SPA from the impacts resulting from a net increase in the number of dwellings. This is due to both additional recreational pressure on the SPA as well as the impact of cat predation on the protected bird species. It is not considered that the one for one replacement of existing habitable dwellings is likely to have an impact on the SPA.
400m to 5km zone: Within this zone of influence, it is likely that additional residential dwellings (either alone or in combination with other new dwellings) are likely to have a significant effect on the SPA unless mitigation measures are put in place. Avoidance measures must be delivered prior to occupation of new dwellings and provided in perpetuity. Measures must be based on a combination of Strategic Access Management and Monitoring (SAMM) and the provision and/or improvement and/or maintenance of Suitable Alternative Natural Greenspace (SANG).
5km to 7km: Within this zone applications for large scale residential development (50 units or more) will need to be assessed on an individual basis, in consultation with Natural England, to ascertain whether the proposal would have a significant adverse impact on the SPA. This assessment would involve a screening of the likely significant effects of the development and where required undertake an Appropriate Assessment under the Habitat Regulations.
The Council’s Interactive Policies Map facilitates the search of an area or address to establish which zone of influence it may fall within: https://www.planvu.co.uk/rbwm/