Approximately 600 tonnes of sediment was removed over seven weeks. The area dredged spanned from the Causeway Road Bridge to upstream from the pedestrian bridge, on Peel Terrace.
Sediment will continue to dewater for an additional 6-8 weeks whilst being tested for the presence of acid sulfate soil, treated if required and transported off site for reuse. It is expected these works will be completed by August 2022.
Water quality in the river was closely monitored for the duration of the works to ensure no detrimental impacts from the dredging operation and the dewatering of the sediment occurred.
Mayor Grant Henley said, “This first stage of sediment removal in the Lower Vasse River has been widely successful, with a large quantity of sediment removed. This represents a significant amount of nutrients which won’t be released next summer, going towards improving water quality in the river”.
A thick layer of nutrient-rich, fine organic sediments has accumulated throughout the Lower Vasse River, providing an internal source of nutrients that contributes to algal growth and poor water quality in summer. While sediment removal alone is not expected to prevent algal blooms occurring in the river, it is an important step for improving water quality.
Planning for additional sediment removal is progressing, with a future stage planned for later this year. A funding application was also submitted to the WA Government Community Stewardship Program for additional sediment removal in 2023.
This project is part of Royalties for Region’s Healthy Estuaries WA and Revitalising Geographe Waterways programs. These State Government initiatives aim to support the long-term health of our south-west estuaries.
More information about the project is available at www.busselton.wa.gov.au/lower-vasse-river-management.