Urban River Restoration, River Condition Assessment & Biodiversity Net Gain (BNG) Case Study

Urban River Restoration and Biodiversity Net Gain Opportunities

For the Love of Water (FLOW) CIC was commissioned to assess the potential for river restoration and Biodiversity Net Gain (BNG) delivery across a series of urban river sites.

This work combined a catchment-wide BNG scoping assessment across multiple locations with a detailed River Condition Assessment (RCA) at a priority reach, providing both strategic and site-level insight.

The aim was to identify where meaningful, deliverable restoration could improve river condition and generate measurable biodiversity uplift.

As a not-for-profit, our focus is always on ensuring BNG drives genuine ecological recovery, with funding reinvested into long-term river health.

What is Watercourse Biodiversity Net Gain and River Condition Assessment

Watercourse Biodiversity Net Gain (BNG) links development to measurable improvements in river condition, including:

Habitat diversity
Channel morphology and natural processes
Riparian condition and connectivity
Fish passage and ecological resilience

River Condition Assessment (RCA) underpins this by providing a structured, evidence-based evaluation of river health using MoRPh surveys and desk-based river typing.

Together, these approaches allow restoration to be quantified, funded, and secured for the long term.

Catchment-Scale River Surveys and BNG Modelling Approach

Across the project, we undertook:

Walkover surveys across multiple river reaches
Mapping of riparian and in-channel encroachment
Targeted River Condition Assessments (RCA)
Biodiversity Metric modelling to estimate baseline and uplift potential

This provided a clear framework to prioritise sites based on ecological benefit, feasibility, and BNG unit generation

River Condition and Restoration Opportunities Across Urban Catchments

Across the wider study area, we identified a spectrum of river conditions:

Heavily modified urban channels with limited natural processes
Partially naturalised reaches with strong recovery potential
Higher-quality sections where protection is the priority

The most effective restoration interventions consistently included:

Removing engineered banks and revetments
Reintroducing natural channel features (wood, berms, flow diversity)
Improving riparian buffers
Addressing impoundment from weirs

Constraints and Challenges in Urban River Restoration

Key constraints identified across the project include:

Large weirs causing extended impoundment
Urban infrastructure and adjacent land ownership
Limited space for channel re-naturalisation
High baseline condition limiting uplift potential in some areas (a nice problem to have!)

Balancing restoration with community access and existing infrastructure is often a key consideration.