Hallam Valley Wetland - 2022/23 Sediment Pond Desilts

Dandenong South, Vic

Project Duration

January to April 2023

Client

Melbourne Water

Project Value

$ 463k

As part of the FY22/23 Melbourne Water Desilt Program for Melbourne Water, Jaydo was engaged for the sediment removal of three inlet ponds at Hallam Valley Wetland. Each individual pond needed to be dewatered and inlet water flows managed, to allow for machinery to enter the ponds to remove all built up sediment within them.

key challenges

As the sediment ponds were interlinked into the larger wetland system the majority of the upper wetland system needed to be dewatered. Once the dewatering process was completed continuous bypass pumping was implemented to ensure that the sediment pond remained water free during
the desilting process.
Rain events – as the wetland system has three inlet points and a significant catchment area the system filled up extremely quickly after any rainfall event. To manage this Jaydo had several pumps on
site located in key locations to ensure the water was moved effectively and efficiently through the system.
Hallam Valley Wetland system is contaminated with alligator weed which required all removed sediment to be stockpiled on plastic then geofabric and to be bunded with haybales to contain
the material. Prior to disposal all trucks transporting the material were required to be lined with builders plastic, prior to being loaded.
The clay base of the ponds were extremely soft causing Jaydo’s machinery to become bogged, to prevent this and to reach the centre of the ponds, steel plates were used to create a safe working platform.

Key innovations

Steel plates were used to access the centre of the ponds and to create a safe working platform for our machinary, by preventing them from becoming stuck in the soft clay liner of the sediment ponds.