Awareness of the biodiversity crisis is leading developers to commit to protection rather than merely mitigation, which opens a wide range of design choices. Do new roads necessarily need to leave a footprint more damaged that the pre-construction environment? Incorporating nature from the outset of the design process involves shaping routes to avoid valuable biodiverse areas like wetlands or ancient woodlands. The wider intersections with water, geology, and topology are as important to navigate as the demands of existing infrastructure and the needs of the local community.

If the project involves an urban area, it becomes an opportunity to enhance biodiversity in previously degraded sites to increase diversity, aid in flood protection, and provide areas for community enjoyment. With the Pocket Parks initiative in Islington, for example, WSP helped build a project plan and financial framework to turn underused grey stub roads into biodiverse public spaces which reduce both flood risk and air pollution.

Stakeholder consultation

Linear infrastructure is planning for the future, which is why incorporating biodiversity improvements into transportation design requires early and diligent engagement with all stakeholders, including the surrounding community. Full transparency includes not only honesty about any design-related trade-offs but also the demonstration of quantifiable data proving how nature-inclusive design will lead to better outcomes for everyone.

Public consultations provide a platform for stakeholders to voice their concerns and contribute to the decision-making process, so each project addresses local community needs and values. Obtaining dedicated local buy-in is a priority. Implementing a green bridge or wetland without support can lead to elevated costs with minimal return. Additionally, social needs must also be balanced with nature considerations, particularly in remote locations. The only way to find the balance point is through thorough dedicated consultation.

Indigenous communities are emerging as invaluable knowledge holders when incorporating nature into design. Consulting with Indigenous Peoples allows for the integration of traditional learnings early into the planning process, vastly increasing the likelihood that they and other custodians of the land will support design decisions and choices.

In Windsor, the development team for the Rt. Hon. Herb Gray Parkway consulted with the Walpole Island First Nation on the design and construction of the complex highway project, which includes the 100m-wide T 5 Eco Passage across highway 401. The collaboration enabled the preservation of at-risk species and contributed to the restoration of the surrounding ecosystems, and even influenced the aesthetic and artistic elements of construction.

The Looe Harbour Flood Defense Scheme for Regeneration is another example of innovation in community engagement. The portal clearly explains the proposed harbour development, the scope of the environmental impact assessment, and the subsequent steps of the process, all accompanied by photos and diagrams. There’s also an easily accessible tab for feedback, allowing the local community the chance to understand and interact with the project.

Environmental assessment

Well-regulated environmental assessments (EAs) provide an opportunity to develop innovative new nature-positive solutions. Following the order of the mitigation hierarchy (avoidance; minimisation; restoration; offsetting) is crucial if we are to design linear infrastructure positive impacts on nature because avoiding loss is the first priority.

New digital tools, like remote sensing, automatic trail cameras, and data analytics, are also changing the way environmental impact assessments are performed. These technologies enable more accurate and comprehensive data collection, allowing for better prediction and management of potential impacts.

One such innovative tool is WSP’s GoldSET, a web-based set of tools that integrates a rigorous multi-criteria analysis (MCA) approach with geospatial information management. Clients use it to evaluate alternatives or monitor ongoing projects with data from environmental, social, economic, and technical dimensions. This systematic process quickly identifies the most sustainable corridor or site, which facilitates cooperation among multiple stakeholders.

In addition to technological advancements, regulatory frameworks play a crucial role in driving positive change. The U.K.’s Biodiversity Net Gain (BNG) is an excellent example of how national legislation can lead the way. BNG requires developers to generate a 10% biodiversity gain, measured by the quantity and quality of habitat in the proposed development boundary. This biodiversity gain can be delivered entirely on-site, mixed between on- and off-site improvements, or through the purchase of statutory government biodiversity credits, which will be used to fund habitat creation across England.

Project engineering & construction

The next key step is integrating nature-based solutions into the engineering and construction phase. Replacing grey infrastructure – traditional stormwater infrastructure in the built environment – with green alternatives minimises flood risk and enhances climate resistance, often at a reduced cost. Bold design and construction choices are available to dramatically increase nature-positive outcomes, including:

• Bioswales: Small channels that absorb, concentrate and convey stormwater, bioswales also remove debris and pollution, aiding in the recharge of groundwater.
• Naturalized highway crossings dramatically reduce wildlife mortality. In Banff, wildlife overpasses and underpasses have dropped animal-vehicle collisions by more than 80%, and have encouraged the construction of wildlife passes in several other countries and continents.
• Permeable pavements like porous concrete filter water through and into the soil instead of contributing to runoff. These alternatives are up to 50% less expensive to install than traditional pavements, and generally cheaper to maintain.

Building nature into design means considering all the ways a project has embodied impacts on nature. The impacts of a new transportation route extend beyond the finished form, beginning with the extraction of raw materials and occurring throughout the entire supply chain.

Operations and maintenance

Soft Estate, the term for the verges, hedgerows, and planted areas along highways and roadways, is undergoing a renaissance. The growing cultural understanding of the serious need to protect biodiversity has influenced public opinion. Instead of being considered messy landscape barriers, naturalized verges are evolving into thriving biodiversity corridors. 
By reducing grass cuts to twice a year and removing topsoil to allow wildflower spread, National Highways is creating shelter for pollinators and managing invasive species while cutting maintenance costs. The agency also uses satellite mapping to track habitat changes in their Soft Estate and monitor the improvement of biodiversity across their entire road network.

Think big: act now

Biodiversity is no longer at the bottom of the list when it comes to transportation design. Instead, it provides an opportunity to create lasting impact, benefiting the wider ecosystem services for local communities in the sense of flood relief and increased green space and contributing to national and global targets for nature recovery.

Integrating nature into the design process offers a chance to make significant, positive changes. The Stitch, an ambitious project in Atlanta, aims to reclaim the Downtown Connector by adding over 56,000 square meters of green space to the city’s core. This bold project will also enhance community access to housing, jobs, and resources. Other large-scale transportation interventions that boost biodiversity include eco passages, exclusion fences, fish passes, and green bridges. Governments often recognize the value of these schemes and provide support to help gain approval. 

We’re in the process of recalibrating the ways in which our built environment interacts with the natural world. The best way to start is right at the beginning, by design.

Ben O'Hickey - Senior Advisor, ESG and Nature Advisory 

Ben O'Hickey is a Senior Advisor, ESG and Nature Advisory at WSP based in Toronto with a specialist knowledge in natural capital, corporate biodiversity strategies and environmental assessments. Ben works across the variety of sectors including mining, infrastructure and finance to support clients with nature related disclosure requirements such as TNFD and support them in the development of corporate biodiversity strategies. Ben previously worked at WSP UK in the Nature advisory team where in particular he supported client navigate the new mandatory Biodiversity Net Gain policy and where he was the lead author of WSP UK’s Nature Positive Report. Ben is a chartered environmentalist and a Member of Institute of Environmental Management and Assessment (IEMA).