Direct Rainfall Modelling
We developed bespoke direct rainfall hydraulic models to test different building locations and footprints, analysing surface water flow paths and flood displacement with each iteration.
Case Study
Dew Drop Inn, Peacehaven
Managing complex surface water flood risk to deliver a safe, resilient, and policy-compliant mixed-use redevelopment on a challenging coastal site.
Mixed Use
Surface Water
SuDS
Location
Peacehaven
Project Type
Mixed Use
Flood Zone
Zone 1
Flood Risk
1 in 30 year
The Challenge
High surface water risk despite Flood Zone 1
The redevelopment of this former public house into a mixed-use scheme with office space and residential flats presented significant flood risk challenges despite its favourable fluvial classification.
Environment Agency pluvial data showed the site was at high risk of surface water flooding, with potential flooding during a 1 in 30 year event. The chalk geology precluded infiltration-based drainage solutions, and building guidance standards required a 10m buffer distance from structures.
Our Approach
Iterative design through hydraulic modelling
Optimised Building Design
Working iteratively with the design team, we matched the building footprint to the existing structure while adjusting access and layouts to minimise flood impact.
Vulnerability Zoning
Ground floor space was allocated to less vulnerable commercial units, with residential uses placed on upper floors to manage residual risk.
Comprehensive Drainage Strategy
Surface water and foul drainage design with on-site attenuation, connection to existing networks, and SuDS aligned with CIRIA C753 hierarchy guidance.
Stakeholder Engagement
Early consultation with regulators
We engaged early with the Lead Local Flood Authority and Southern Water to ensure our drainage strategy aligned with their requirements and expectations.
This proactive approach avoided late-stage objections and ensured a smooth planning process with no technical holdups.
- Early LLFA engagement
- Southern Water consultation
- Coordinated technical approach
- Aligned expectations from outset
The Result
A safe, resilient, and policy-compliant redevelopment that successfully managed surface water flood risk while avoiding increased flooding to neighbouring areas.