Record sediment capture helps keep Lake Hayes clear

The improving condition of Lake Hayes continues to provide encouragement for the community working to restore the lake, with clearer water and lower phosphorus loads being observed heading into winter mixing.

A major contributor to that progress has been the outstanding performance of sediment traps installed on the Dagg family farm. These traps capture run-off into Mill Creek  from above the farm including  Mt Dewer, Coronet Peak and new cycle trails. In years past this sediment and associated nutrients would have made its way to the lake.

Andrew Dagg with his digger showing what 670 tonnes of sediment looks like

Following the exceptionally wet spring of 2025, the traps captured record volumes of sediment during their third year of operation. The amount removed this year alone was equivalent to the combined total from the previous two years.

• Year 1: approx 400 tonnes removed

• Year 2: approx 600 tonnes removed

• Year 3: approx 1,070 tonnes removed

The result highlights both the scale of sediment movement that can occur during major rainfall events and the importance of intercepting that material before it reaches the lake.

The Dagg family’s ongoing commitment to the project has played a significant role in helping keep total sediment inflows to the lake below ~400 tonnes during 2025 – an important milestone for the long-term recovery of the lake ecosystem.

A photo showing Andrew Dagg beside a digger and one of the dried sediment traps tells the story better than any graph. Material that would previously have washed directly into Mill Creek and ultimately into the lake has instead been trapped, dried and removed from the catchment.

Nearly empty.