Transport for London (TfL) engaged Arcadis for the permitting process of their proposed Silvertown Tunnel under the Thames River.
For the permit, we were required to demonstrate that there would not be any residual effects on biodiversity. We wanted to demonstrate an overall net gain applying the Biodiversity Action Plan and Mitigation Strategy (BAP MS).
The site was an urban brownfield habitat, undervalued for biodiversity and other natural capital values.
The goal of the BAP MS was to minimize, quantify, qualify and monetize biodiversity impacts and ultimately deliver a net gain for biodiversity.
Targets and parameters were set for onsite and offsite mitigation. We monetized different ecosystem services and allocated a maximum deficit value for natural capital to support the offsite delivery. This helped to communicate the investment requirements to the client, provided targets and auditable values for such mitigation. In addition, this study served as a pilot example for future assessments and stakeholder engagement.
This approach has the potential to release valuable land for development and to establish a robust process for on and off-site mitigation to ensure that we retain valuable and functional habitats for the local and wider community.
In the case of Transport for London’s (TfL) proposed Silvertown Tunnel under the River Thames, Arcadis was able to demonstrate a net gain in biodiversity while maintaining or enhancing ecosystem functions.
No Net Less (NNL) has been achieved through a combination of onsite mitigation and off-site compensation using natural capital valuation. This reduces project costs by avoiding the need to acquire expensive, adjoining land with complex ownership issues. Stakeholder expectations have been managed and regulatory obligations met, both critical requirements to secure the necessary planning approval.
Dr. Martina Girvan (firstname.lastname@example.org) Technical Director Ecology and Arboriculture London
Gregor Pecnik (email@example.com) Environmental Economist