Understanding where fresh water meets the sea

Nelson Lagoon in 2016.
Nelson Lagoon in 2016.

The way we look at Cuttagee Lake, Nelson Lagoon and Middle Lagoon may change after the completion of an extensive study.

Bega Valley Shire Council’s Draft Targeted Catchment Management Plans of the estuaries was conducted by Bega based environmental assessment, research and management consultants, Elgin Associates, and included extensive public consultation with nearby communities.

Estuaries are dynamic ecosystems where saltwater from the sea enters creeks and rivers with the rise and fall of the tides.

They are recognised for their importance in decreasing the effects of flooding and storm surges, their importance commercially and recreationally and their cultural significance all over the world as food sources and transportation routes.

“The three estuaries selected for this study are all extremely sensitive to catchment disturbance which directly affects water quality,” council’s coastal management officer Kyran Crane said.

All three are defined as intermittently closed and opened lakes or lagoons or ICOLLs, and “possess significant ecological, recreational and socioeconomic values”, he said.

Cuttagee Lake in 2014

Cuttagee Lake in 2014

“Issues such as unsealed roads, intensive land use, natural and man-made erosion all impact on water quality,” Mr Crane said.

“This impact can be particularly intensified for ICOLLs as there is reduced tidal flushing when the entrance bar is closed, therefore catchment inputs can inadvertently affect a range of water quality parameters.”

The study highlights artificial opening at Middle Lagoon as occurring since the late 1800s.

“The historical management practice of regularly opening the lagoon entrance maintained lower water levels in the estuary to provide regular access to low-lying lands for grazing and other agricultural uses,” the study says.

According to the study, this practice has caused a “colonisation of foreshore areas by vegetation and tree species typically restricted to higher areas”, which is beginning to shift back since the practice was made illegal.

Nelson Lagoon has the issue of private property and oyster commercialism via Tathra Oysters, while Cuttagee Lake faces erosion problems with low lying roads.

Estuaries are one of the most important places on the Australian landscape to Indigenous people according to Wallaga Lake Elder Warren Foster Sr.

Wallaga Lake's Warren Foster Sr.

Wallaga Lake's Warren Foster Sr.

“It’s our main source of food supply” he said.

“Certain plants tell us what food is ready to eat, like oysters and we still maintain that knowledge.

“If we had too much iodine from the seafood and salt we’d go to other meat like wallabies so it gave us a balanced diet.”

Mr Foster said estuaries a place where medicines grow, and he said some species are becoming more difficult to find.

“There’s lots of those plants that are starting to disappear,” he said.

Mr Crane said council has comprehensive Coastal Zone Management Plans in place for all of its major estuaries, but some of these smaller ICOLLs can be managed and rehabilitated without the need for full scale plans.

The plans will be on public exhibition until September 20.