13/10/2025
Case Study: Integrated Drainage System – Coffs Harbour Bypass
In ground-engineering projects, drainage is the quiet achiever — unseen, but critical to performance and longevity.
At Shotcrete Australia, we design and deliver integrated drainage networks that work hand-in-hand with our retention and shotcrete systems. From hydrostatic pressure relief drains that manage in-ground water, to precision-formed bench channels that control surface runoff — every detail matters, especially in high-rainfall and humid regions.
Our recent work on the Coffs Harbour Bypass showcases this capability in action — combining innovation, precision, and resilience across multiple lifts of retention and drainage works.
💧 Project: Coffs Harbour Bypass
🏗️ Client: Transport for NSW
📐 Scope: Integrated hydrostatic relief + surface drainage network
The Solution
We implemented a dual-function system combining:
• Hydrostatic pressure relief drains with strip drains, outlets, and subsurface pathways to relieve groundwater pressure.
• Bench runoff channels and outlet drains, precision-formed in shotcrete to safely direct surface water down slope profiles.
Each lift was built with exacting tolerance, connecting in-ground relief lines to runoff drains through purpose-built transitions — ensuring controlled, predictable, and durable water management.
The Outcome
✅ Mitigated groundwater pressure + stormwater load
✅ Enhanced retention system stability
✅ Improved surface water flow across multiple bench levels
✅ Full compliance with TfNSW specifications
This project exemplifies our ability to integrate drainage design with complex shotcrete systems — delivering resilient infrastructure built for Australia’s toughest conditions.
