Darwin : Hidden Valley Motorsports Complex Civil and Erosion control upgrades

For: Department of Planning Infrastructure & Logistics

Contract Value: $1,986,000

Description: Works were aimed at remediate existing flood damage and minimise future damage. These works are broken down into several separate works:

• Improvement 1 – Retention basins in northern carpark - provide 8 hour retention dams for a Q100 storm event across the three watercourses. This will increase the capacity and performance of existing drainage infrastructure by approx. 50%.

• Improvement 2 – Turn 1 erosion control – erosion control measures between turn 1 and 2. The current drain needs to be cleaned often and is not working properly. Earth mound level bank is proposed, which will improve the drainage in the area.

• Improvement 3 – Turn 1 surface runoff – earthworks need to be done to re-contour and provide levee banks to redirect stormwater runoff away from the track at turn 1.

• Improvement 4 – Turn 2 to 4 embankment – a proposed 600mm high rock barrier and reworked drain behind 1 line of protection. Currently the stormwater runoff overflows at the existing kerb along the speedway pit area on to the racetrack below.

Variation was included to construct a viewing mound at turn 10. Works included concrete footings, block work retainer walls, subsoil drainage, bulk filling, hand rail/ balustrades, concrete slabs and associated works

Results: Project successfully managed on time and to budget.