NHRR Source Protection Zone
Groundwater Protection & Drainage Strategy in SPZ
Location: Lincolnshire
Project: North Hykeham Relief Road – Catchment 10
Focus: Groundwater Protection in SPZ2
The Challenge
A section of the NHRR falls within a Source Protection Zone 2 (SPZ2), where infiltration drainage posed a risk to public water supplies. The goal was to allow sustainable drainage without compromising groundwater quality.
Our Approach
Courous Ltd developed a multi-layered pollution mitigation strategy aligned with HEWRAT, LA113, and CIRIA SuDS guidance.
Key Measures:
🌀 Vortex separators for removing hydrocarbons and metals
🌱 Sediment forebay and grass channels for natural filtration
🛑 Penstock valves for emergency shut-off during spills
📊 HEWRAT and spillage risk assessments demonstrating compliance
🧪 Ground investigation confirming low permeability and no groundwater within 10m
Outcome
✅ Infiltration drainage approved within SPZ2
✅ Pollution risks mitigated to “acceptably low” levels
✅ Fully compliant with EA and groundwater protection policies
✅ Sustainable, maintainable, and resilient design
This project highlights Courous Ltd’s capability to deliver compliant drainage solutions in sensitive groundwater zones, balancing environmental protection with practical design.