Vasse Estuary Gates Opened Mixing Seawater To Reduce Algal Blooms

Vasse Estuary Gates Opened Mixing Seawater To Reduce Algal Blooms

Western Australia Minister for Water Dave Kelly

Science Backs Vasse Seawater Inflow To Reduce Algal Blooms

Victor P Taffa

  • Vasse gates opening to support the ecology of Vasse Wonnerup rivers and wetlands
  • Gate opening strategy the result of three years of scientific trials
  • Rapid input of seawater is predicted to reduce major algal blooms

Gates at the Vasse Estuary surge barrier will be opened this month to let seawater mix into the estuary in a plan to reduce algal blooms over summer.

“Toxic algal blooms are a regular occurrence in the Vasse Estuary over summer, and poor water conditions have led to major fish deaths, with the most recent in 2014.” Minister for Water Dave Kelly said.

Based on a successful 3-year scientific trial carried out by the Department of Water and Environmental Regulation, the early and rapid input of seawater is calculated to reduce major algal blooms that occur each year over summer upstream of the Vasse surge barrier. 

Trial revealed that the timing, frequency and period of time the gates were opened produced different results, and the chosen opening strategy for this summer is the one that provides the most benefit to water quality.

A study to better understand the relationship between water flows and the ecology of the Vasse Wonnerup wetlands is also underway.

“Protection of the Vasse Wonnerup wetlands is an issue of importance for the local community.” South West Region MLC and Vasse Taskforce chairperson Dr. Sally Talbot said.

Departments of Water and Environmental Regulation and Biodiversity Conservation and Attractions have partnered with Murdoch University to carry out the 2-year study to monitor seasonal water levels and water quality alongside aquatic plants, invertebrates, fish and birds.

Internationally listed Vasse Wonnerup wetlands support tens of thousands of birds a day over summer, and the study will assess any impacts to the ecology through possible changes to the management of water flow into the wetlands.

Both projects are part of the Revitalising Geographe Waterways initiative.