NHRR Source Protection Zone

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.