History was made in August this year when a joint initiative of Gosford City and Wyong Shire Councils, pumped the first drops of water along the $120 million Mardi-Mangrove Link, the largest infrastructure project on the NSW Central Coast in decades.
By linking the largest dam in the region, Mangrove Creek Dam, with Wyong River, Ourimbah Creek and the smaller Mardi Dam, the Mardi-Mangrove Link project will help to secure the water supply for the future.
The Mardi-Mangrove Link project is an initiative of Gosford City and Wyong Shire councils with Australian Government funding of $80.3 million provided through the Water Smart Australia Program – Water for the Future initiative, and an additional $40 million combined from the two Councils.
The project is part of WaterPlan 2050, the long term water supply strategy for the region.
It involved:
- a 2.1 kilometre buried water pipeline from Wyong River to Mardi Dam
- a 19 kilometre buried pipeline from Mardi Dam to the existing Boomerang Creek Tunnel leading to Mangrove Creek Dam
- a new pump station at Mardi Dam
- a new pump station beside Wyong River
- an upgrade of the Lower Wyong River weir and fishway.
To keep costs low and limit the impact on the local community a number of engineering innovations were applied during construction.
Project Director Greg McDonald said the most significant of these was to use horizontal directional drilling technology to lay 260 meters of pipe under Wyong River.
“Successful completion of this section meant the project achieved an Australian first for installation of a pipe this size, length, and pressure rating using this technology.
“This method was faster, safer, cheaper and less intrusive for residents than other techniques such as microtunnelling.”
The project was also the first to install an integrated fishway and flow gauge to bring about environmental improvements. The flow gauge monitors the amount of water passing the weir and transfers the data back to the pumping station.
This limits the impact on local wildlife and the environment by taking water according to the natural flow of the river.
The fishway was designed on leading edge practice in Europe and will also help to increase local fish stocks by operating in all but the driest of times.
The Mardi-Mangrove Link will help to boost dam storage levels, speed up drought recovery and help protect the region against future extended periods of below average rainfall.
This will ensure there is enough water for a growing population and may assist in the easing of water restrictions.
