Sediment Removal - Lower Vasse River

⁠⁠⁠The City of Busselton (the City or the Principal) is inviting Tenders from suitably qualified suppliers to provide a methodology and to undertake the removal of nutrient rich organic sediments that have accumulated throughout the bed of the Lower Vasse River and providing safe transportation of contained excavated material off-site to Busselton Transfer Station, Rendezvous Road, Vasse.

The City of Busselton aims to remove approximately 70 per cent of accumulated sediment from the target area, and as close to the riverbed as possible. The Contractor’s methodology needs to be able to achieve this outcome.

As detailed in the RFT02/24 Sediment Removal - Vasse River and in particular Attachment B - Specification

Background information / Compatibility requirements

The Lower Vasse River is impacted by high nutrient concentrations (eutrophic conditions), exposed sediments and seasonal algal blooms. Noxious algal blooms persist throughout summer and autumn each year, impacting public amenity and water quality.

The layer of nutrient-rich, fine organic sediment that has accumulated throughout the lower reach of the river exhibits an average depth of approximately 500mm. The accumulated sediment provides a significant internal source of nutrients that contributes to ongoing algal growth.

Removing the bulk of these sediments is a recommendation from the Lower Vasse River Waterway Management Plan (City of Busselton, 2019).