Waituna Lagoon exceeds 2m level

The Waituna Lagoon was opened to the sea at Walker's Bay yesterday after the water level exceeded the 2-metre trigger level.

Environment Southland environmental management director Warren Tuckey said the water level was dropping very slowly and more rain was forecast this week.

''This was an optimum time for opening as spring tides were forecast,'' Mr Tuckey said.

Heavy machinery was used to dig a channel allowing the lagoon to drain into the sea. It was last opened in October last year and closed naturally only recently.

Environment Southland aquatic ecologist Andy Hicks said the October opening had resulted in a missed key growth period for ruppia, a species of sea grass used to indicate the ecological health of the lagoon.

''Studies of previous openings indicate that if we open the lagoon now it will close before summer, which is important because it allows macrophytes (similar sea grasses) to grow in the freshwater,'' Dr Hicks said.

It would also minimise the opportunity for nuisance algal growth to occur, he said.

The opening of the lagoon was funded by Environment Southland, and was endorsed by the Lake Waituna Control Association.

The Southland Times