Mariners Cove

The Mariners Cove project on the Peel estuary in the City of Mandurah comprised a total of 1,000 canal and dry lots and included design, documentation and contract administration of extensive earthworks, breakwaters, canal walling, drainage, sewerage, sewer pumping stations (standard and vacuum), boat ramps, car parking and the floating marina.

A critical achievement for the project has been major canal layout revisions, which incorporated all water based and dry lot design experience accumulated by TABEC personnel over twenty years, to achieve a considerable net project enhancement that was readily acknowledged by the developer.

Mariners Cove presented a major geotechnical challenge due to existing ground conditions, with a silty layer of the order of 1m – 2m thick, that required either removal of the silty material or ground improvement to raise the lot site classification from a ‘P’ to an ‘S’. Rather than the constraints imposed by preloading and consolidation, the preferred solution was over excavation of material down to -5m AHD into the underlying limestone material which was then blended insitu with the dried silt. This process achieved a number of objectives; eliminated the need for disposal of impervious silty material and replacement with clean sand fill, reduction of the silt organics content to an acceptable level within the fill material, reduction in fines ratio for increased permeability for compaction and the advantage offered by blending limestone to treat potential acid sulfate soil conditions.