For Affinity Water
Tree surveying, mitigation and monitoring
We were asked by a major water utility company to conduct a BS5837:2012 tree survey to inform the installation of a new 5 km pipeline at Cockfosters Water Tower.
The survey covered highly protected urban and woodland areas which included numerous individual and group Tree Preservation Orders (TPO) and Conservation Areas. Our Consultants worked alongside Affinity Water by filing the necessary planning applications across this protected environment.
Arboricultural Impact Assessment, Tree Constraints Plan and Tree Protection Plan
Accurate data, recorded with advanced laser technology, included the GPS location of nearly 900 trees, groups of trees and hedgerows. This data was entered into a bespoke tree management software programme on-site. Our Consultants exported the data onto a spreadsheet to support the creation of plans for the development and protect the existing trees. A Tree Constraints Plan identified the location of any existing TPOs, Conservation Areas, and the Root Protection Area of all trees and groups. An arboricultural Impact Assessment Plan identified where trees were needed to be removed, and where retained trees had the potential to be affected by the development. A Tree Protection Plan showed the location and type of measures necessary to protect the existing trees.
Mitigation and monitoring, to accordingly replace tree losses and protect existing trees
Where tree removals were deemed necessary, the focus was to remove the poorer quality trees with shortest life expectancy in favour of safely retaining those with greater arboricultural, amenity, and/or landscape value to the area. The methods included in the Tree Protection Plan were set out to mitigate the potential impact of the development on the retained trees. These included minor pruning operations to ensure no construction works came into contact with trees, fenced off Construction Exclusion Zones, geocell ground protection where necessary to mitigate soil compaction, and no-dig methodology such as using hand tools, air-spades and vacuum excavators to carry out trenching within Root Protection Areas. On-site monitoring where works were carried out within the vicinity of retained trees ensured the specification outlined in our reports was followed.
In order to mitigate for tree losses our Consultants created a Landscape Mitigation Plan including suitable replacement species, design layout and methods to enable the client to implement the necessary volume and type of new planting.
