A CLASS RESERVE RESTORATION

Rehabilitation of the Perth
Seawater Desalination Plant Pipeline within a Class A Reserve between
Thomsons and Kogolup Lakes and surrounding areas.

360 Environmental has worked directly with the Water Corporation and the Department of Environment and Conservation (DEC) to restore native vegetation between Thomsons and Kogolup Lakes within the A Class reserve and surrounding areas after the main desalination pipelines were installed.

Weed control programs were implemented prior to the planting seasons to help eliminate any competition for native seedlings. To further increase the survival rates of the green stock, mulch composted to Australian Standards (AS 4454), certified weed and dieback free was spread throughout the rehabilitation sites at an optimal depth of 100mm before planting commenced. Mulch not only suppresses weed growth, it also helps to retain moisture content and provides nutrients for the seedlings when it biodegrades into the topsoil and soil layers. All seeding was carried out prior to the planting and mulching programs. Native provenance seed was collected and broadcast in June with a bulking agent to ensure an even coverage of seed. Seedlings for the reserve were grown from locally collected seed to ensure the provenance was maintained and seedlings were endemic to the area. There has also been some natural recruitment of native species germinating throughout the sites, which maybe partly attributable to good topsoil management. Green stock used outside of the A Class Reserve were sourced from dieback accredited nurseries.

All seedlings were planted with a slow release native fertiliser tablet to supply nutrients to the seedling over a period of time. Rabbit proof fences were installed at the entrance to the A Class Reserve and within the reserve to protect the seedlings. All green stock planted in areas outside the fences were protected with tree guards, which are maintained monthly until they can be removed. Site Meetings were held regularly for the duration of the project to ensure quality control measures and timelines were kept. Weekly toolbox meetings were established to improve project quality and efficiencies. All specifications for the project were followed and the planting program was completed successfully within the timeline given.

The 2006 plantings have progressed remarkably well both inside the reserve and the Buffer Lakes, showing a high density and a large diversity. Priority 4 species Dodonaea hackettiana has progress exceptionally well even dominating some planted areas. Areas where the success rate was not as positive, infill planting was undertaken as a part of the 2007 program.

This successful rehabilitation project will be the subject of ongoing maintenance and monitoring. Weed control throughout the site is instrumental in producing a rehabilitation area that has a high diversity, density, is self sustaining and aesthetically pleasing.