Baradene College Gymnasium

Baradene College Gymnasium

Client: Watts & Hughes Construction
System: StormLite® Underground Detention System
Total Capacity: 56,400 L

Project Overview

Watts & Hughes Construction partnered with APD to deliver a stormwater detention system for the new gymnasium at Baradene College.
The original design called for four joined StormLite® tanks (4 × 12,700 L) installed under a landscaped lawn area, providing a combined storage capacity of 50,800 L.

Challenge

After the tanks were ordered, the project scope changed — the school decided to build a car park directly above the tank area.
This change introduced several structural and engineering challenges:

• The concrete slab above needed to bridge load across four tanks, but APD’s standard detail requires a six-metre ground section after the third tank to support the slab.
• Extending the footprint to meet this requirement would have made the system too wide for the available area.
• The sloping site created uneven cover depths, with one end exceeding the standard maximum depth.
• Adjusting the tank layout meant the outlet invert level also had to be raised, reducing usable capacity.

Solution

APD proposed an alternative configuration — three longer StormLite® tanks — which reduced the overall system width while maintaining structural integrity for the concrete slab above.

Two additional design adaptations were required:

1. Depth of Cover:
   APD engaged an independent engineer to develop a site-specific design and installation detail, tailored to the soil conditions and increased cover depth at one end.
2. Outlet Invert Level:
   To compensate for the raised outlet, 5,600 L of additional “dead volume” was added to the tanks, ensuring the total usable detention volume was maintained.

Final configuration:
3 × 18,800 L StormLite® tanks (1,200 mm dia × 17 m long)
Total capacity: 56,400 L

Outcome

Through careful redesign and collaboration with the engineering team, APD delivered a cost-efficient and structurally compliant solution.
The revised configuration enabled the car park construction to proceed safely above the installation — without increasing the project’s footprint or significantly impacting cost.

This project demonstrates APD’s ability to adapt designs quickly while maintaining compliance, performance, and client confidence.

Client Feedback

“You have been exceptional to work with… extremely pragmatic, refreshing.
Simply put, for suppliers like yourself and APD — this is how you obtain repeat business.”