Crawley Green Infrastructure & Biodiversity Net Gain Sites

The Client

Crawley Borough Council (CBC) commissioned a strategic study to identify and prioritise opportunities for Green Infrastructure (GI), Biodiversity Net Gain (BNG) and nature recovery across the borough.

The work supported CBC in responding to the Environment Act 2021 and the mandatory requirement for development to deliver more than 10% measurable BNG, while also supporting the emerging Local Plan and its proposed use of Urban Greening Factor (UGF).

Importantly, the project was designed to move beyond simply identifying theoretical BNG opportunities. It provided CBC with a clear, evidence-based route from borough-wide opportunity assessment through to BNG-ready sites that could support future mitigation.

The Work

The initial commission covered 17 key sites identified by CBC. The work included ecological desktop assessment, habitat mapping, site prioritisation and opportunity assessment to identify where investment in GI, BNG and nature recovery could deliver the greatest benefits.

The sites were assessed against a range of ecological and strategic datasets, including Biodiversity Opportunity Areas (BOAs), Local Wildlife Sites and priority habitats such as urban habitat, deciduous woodland, lowland heathland and lowland meadow.

The assessment helped CBC distinguish between sites better suited to Urban Greening Factor interventions and those with sufficient habitat and land area to provide meaningful off-site BNG opportunities.

The project subsequently progressed into more detailed site-level work, including:

• Baseline BNG assessments and habitat condition assessments.
• Habitat creation and enhancement scenarios.
• Opportunity mapping and prioritisation.
• Habitat Management and Monitoring Plans (HMMPs).
• Feasibility assessments for additional sites.
• Practical discussions with CBC Parks Managers and site management staff to reality-check proposed habitat management and ensure recommendations were deliverable.
• Advice on the practical requirements for establishing and managing BNG sites, including support around the potential use of conservation covenants and habitat banks.

The work ultimately focused on developing a pipeline of BNG-ready sites capable of supporting future S106 or conservation covenant arrangements.

What we did

We worked collaboratively with CBC throughout the process, providing support at each stage of the BNG site identification and development process.

The project began with a longlist of council-owned sites, allowing CBC to understand the borough-wide potential before committing resources to more detailed assessment. This strategic approach enabled the most promising sites to be taken forward for baseline assessment and feasibility work.

Following the initial assessment, we were on-site baselining the selected sites and developed habitat creation and enhancement proposals designed to improve both the condition and connectivity of existing habitats. Recommendations included enhancement of woodland, ponds and heathland, alongside creation of grassland and scrub habitats and improvements to green corridors.

We then progressed selected sites towards BNG delivery through the preparation of Habitat Management and Monitoring Plans based on agreed baseline BNG assessments.

A key part of the work was ensuring that proposals were not developed in isolation from those responsible for managing CBC's land. Our team engaged with Parks Managers and other relevant site staff to understand existing management, operational requirements and practical constraints. This helped ensure that the proposed habitat creation, enhancement and long-term management measures were both ecologically appropriate and realistic to deliver.

We also provided wider strategic support to CBC, including guidance on establishing a framework for securing and delivering BNG opportunities and consideration of how sites could ultimately be positioned for S106 or conservation covenant arrangements.

Alongside BNG, the wider study considered Urban Greening Factor, helping CBC identify where predominantly urban sites could deliver GI improvements through development-led greening measures rather than being treated solely as BNG sites.

The outcome achieved

The project gave Crawley Borough Council an evidence-based pipeline of potential BNG and Green Infrastructure sites, helping the Council move from identifying opportunities to preparing sites for potential delivery.

The results were a practical, deliverable BNG pipeline rather than a purely theoretical assessment — with sites assessed, opportunities identified, management requirements considered and selected sites progressed towards mechanisms for securing long-term biodiversity outcomes.

With ABEC now a Defra-approved Responsible Body, we can support clients through the full BNG process — from strategic site identification and feasibility, baseline assessment and BNG calculations, through to HMMP preparation, habitat bank/conservation covenant support, long-term management and monitoring, and delivery of biodiversity units.

This project demonstrates the value of taking an end-to-end, partnership-led approach to BNG, combining technical ecological assessment with strategic planning and the practical realities of managing land.