Summary

Complete replacement of an ageing stormwater drainage system for a residential property. We installed new PVC stormwater pipes, added additional drainage pits, and connected to the council main to prevent recurring yard flooding.

Project Overview

This Springfield property had been experiencing chronic yard flooding during heavy rain events for over three years. The existing stormwater system, installed when the house was built in the 1980s, consisted of undersized earthenware pipes that had partially collapsed and were blocked with tree root intrusion.

Site Assessment

We conducted a thorough site assessment including CCTV drain inspection of the existing stormwater lines. The camera survey revealed multiple points of failure: collapsed pipe sections, root intrusion from a large fig tree, and inadequate fall on several pipe runs that caused water to pool and back up during storms.

We also assessed the property's catchment areas, including the roof, driveway, and paved entertaining area, to calculate the required pipe sizing under AS/NZS 3500.3.

Scope of Work

The project involved a complete replacement of the stormwater drainage system across the property:

Removal of all existing earthenware stormwater pipes
Installation of 90mm and 100mm SN8 PVC stormwater pipes with correct fall
Construction of three new 450mm square grated drainage pits
Installation of an absorption trench along the rear boundary
New connection to the council stormwater main at the street
Reinstatement of all disturbed landscaping and turf

Challenges

The main challenge was working around the established fig tree's root system without causing damage to the tree. We used trenchless techniques where possible and installed root barriers around the new pipe runs to prevent future intrusion.

Result

The new system was tested during a 40mm rainfall event two weeks after completion and performed flawlessly. The yard remained completely dry, and stormwater was efficiently directed to the council main. The homeowner reported that it was the first time in years they had no pooling water after heavy rain.

All work was completed in compliance with local council requirements and a hydraulic compliance certificate was issued.