Waterways transform our Catchment each year as wetlands, creeks and river systems fill and empty with water.
The Carbanup, Buayanup, Lower Vasse, Sabina, Abba, Ludlow and Capel river systems support local biodiversity and are among 16 major water courses that flow into Geographe Bay. Urban wetlands provide a refuge for wildlife and migratory birds, and sustain a sense of place for our growing community.
Vasse Wonnerup Wetlands
The Vasse Wonnerup Wetlands provide habitat for thousands of waterbirds every year and are recognised internationally under the RAMSAR Convention. The wetlands support over 90 species of waterbirds and have recorded over 30,000 of individual birds at any one time.
Since European Settlement, our waterways have been modified and diverted to allow for agricultural and urban growth. Floodgates were installed near the mouths of the Vasse and Wonnerup estuaries during the early 1900s to prevent flooding of the surrounding agricultural land with saltwater. The floodgates have enabled the expansion of the Busselton town site and transformed our estuaries into more freshwater environments. As part of the flood mitigation for the Busselton townsite, the headwaters of the Vasse and Sabina rivers were diverted in the 1920s in to the Sabina diversion and then the Vasse Diversion Drain following directly into Geographe Bay.
Most waterways in the Catchment used to feed into a chain of coastal wetlands or estuaries, however they now flow directly into Geographe Bay. As a result, the Vasse Wonnerup Wetlands now received around 20% of their pre-European freshwater flows.
Groundwater also flows from the Catchment into Geographe Bay. The superficial aquifer is approximately 10m thick and below this lies the Leederville aquifer, which in turn is underlain by the older and larger Yarragadee aquifer. Both the Leederville and Yarragadee are confined aquifers that are recharged by direct infiltration of rainfall on the Blackwood Plateau. The Capel River is the only perennial river system that intersects the Leederville aquifer; all other waterways receive contributions only from the superficial aquifer and surface runoff.
Water Quality Improvement Plan
The Water Quality Improvement Plan for the Vasse Wonnerup Wetlands and Geographe Bay (WQIP) was released by the Department of Water in 2010. The plan guides management strategies to reduce the flow of nutrients to these important ecosystems. The plan brings together the best available scientific knowledge about the current water quality status of the Vasse-Wonnerup Wetlands, Geographe Bay and their waterways, for the purpose of nutrient management planning.
Our aim is to restore the ecological, cultural and community values of our iconic waterways. We work with our partners to implement the WQIP, including farmers and the community, to prevent nutrients ending up in our precious waterways and Geographe Bay.