Land use changes give cause for hope

By JO-MARIE BROWN

Lake Rotoehu has endured almost a decade of toxic algal blooms but local efforts to remove them seem to be paying off.

Last summer, for the first time since 1994, the lake did not produce blue-green algal blooms and water quality expert Professor David Hamilton said that was great news.

"Rotoehu really does offer some promise in terms of retiring land around the lake's edges and reforestation.

"It shows there is potential, on smaller lakes at least, to make quite an improvement on lake water quality."

Maori land owners and local authorities have reduced the amount of nutrients entering the water by fencing out cattle and sheep and replanting native trees and shrubs.

However, nearby the picture is not as rosy.

Professor Hamilton said Lake Rotoiti was as sick as ever, although February's wet weather caused the algal blooms to disappear temporarily.

Professor Hamilton and students at Waikato University are doing extensive research on how lakes Rotorua and Rotoiti interact.

"We're now starting to develop quite a good understanding," he said. "That will be important if we're going to maintain some level of water quality in these important national treasures."