10/02/2026
Flooding occurred in front of two garages at a residential unit complex in Kensington Gardens. Epic Projects was engaged to provide expert stormwater management advice to prevent future flooding. We completed the design plans and technical specifications, and also provided tendering, contract administration, project management, and construction supervision services to ensure the solution was delivered effectively.
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The property had two separate stormwater drainage systems, one located at the front of the site, and another at the rear, near the garages that were affected by the flooding. The front drainage system collected runoff from the shared driveway and surrounding paved areas near the front units. The rear system, where the flooding occurred, included a 300 x 300 mm grated drain designed to capture runoff from the rear section of the property. This rear drain was connected to a pump chamber containing a submersible pump. The pump transferred water through a rising main, which discharged into the same grated drain at the rear. From there, a 100 mm PVC pipe carried the water to the roadside gutter.
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All roof downpipes from the surrounding residences were connected to a separate underground drainage system. Based on site observations, no connections from the roof drainage system were found to be linked to the driveway drainage system. It was concluded that stormwater from the roofs did not contribute to the flooding issue.
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To resolve the problem, the existing pump was retained and improved the system by installing a new underground stormwater storage tank beneath the common driveway. The tank had a capacity of at least 5000 litres. A new pump was also installed, capable of delivering flows of at least 1.8 litres per second through the existing rising main. Additionally, the original drain grate was enlarged to 450 x 450 mm to reduce the risk of blockages.
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These upgrades successfully eliminated the minor flooding in front of the garages. The works also provided 100 mm of freeboard (protection) above the garage floor levels during a 1-in-100-year average recurrence interval storm event. Overflow along the eastern side of the affected unit was also prevented for events of this magnitude.
