Jenny Horsfield, historian and local writer standing near the former Tuggeranong Creek at the back of the Tuggeranong Homestead.

Historian and writer Jenny Horsfield stands near the old creek course behind the Tuggeranong Homestead. Photo: Melissa Adams

From a sparkling, frog and fish-filled creek catchment to a foul, sulphur-smelling valley that forces residents inside behind closed doors and windows, Tuggeranong is at the sharp end of Canberra's water stench.

Historian and writer Jenny Horsfield said when Tuggeranong Creek was a permanent water source Aborigines held corroborees there, and Europeans later watered their stock and grew wheat on the plains nearby.

In the 1970s, town planners concreted water courses all the way to Lake Tuggeranong, which was too small for its catchment.

Southern ACT Catchment co-ordinator Martin Lind said the causeways had became freeways for sediment, nutrients and rubbish from all Tuggeranong suburbs except Gordon, Conder and Banks, to feed Lake Tuggeranong's blue green algae.

Ms Horsfield said the old creek course remained intact and was quite deep in parts.

''In the two years we had heavy rain, last year and the year before, we had water in there for six months, '' Ms Horsfield said.

''We had fish, we had water birds, we had frogs breeding, so we know that actual creek line is capable of holding creek water.''

Her community group, Minders of Tuggeranong Homestead, has planted native grasses, yellow box and black sallee gums to re-establish the water course, and want the ACT government to make use of the creek and restore an underground aquifer.

Emeritus professor of biochemistry Dr Ian Falconer, who has studied blue green algae for 30 years, said Lake Tuggeranong was the worst of Canberra's lakes, followed by Lake Burley Griffin.

Microcystis, a toxic blue green alga, irritated the skin, eyes and throat. ''If you accidentally inhale spray, you can get pneumonia,'' Dr Falconer said.

The organism surfaces at night and with a dawn wind drifts to shore, rots and stinks.

''The problems if you are just fishing, or carefully kayaking, are not great, but if you are swimming in it, or if you swallow some, if you fall out of your kayak and swallow some, the problems are considerable because the actual algae has a liver toxin in it which is quite harmful,'' Dr Falconer said.

The only way to rid water of nutrients was to run it around and over plants to pick up the nutrients before they flowed into the lake.

A family in Mortimer Lewis Drive which fronts Lake Tuggeranong says the problem has worsened over the eight years they have lived there, peaking last summer.

''The smell was horrendous,'' said Evelyn, declining to give her surname. ''When we go out the front to get in the car, you think, 'Oh no the lake is smelly again'.

''You can't go outside and stand there. It hurts your eyes, it hurts your nose. It is offensive when you have guests. They sleep upstairs on the lake side and they can't open a window because the smell is awful.''

Residents, rowers and community leaders wonder why new units are being built around Canberra's lakes, while blue green algae's summer stench remains unresolved.

The ACT government will bid for $84 million from the Commonwealth to improve water quality but has no commitment for wetlands in Tuggeranong.

Southern ACT Catchment Group chairwoman Glenys Patulny said wetlands had been developed in north Canberra, and incorporated into new suburbs at Molonglo, but not in Tuggeranong.

''The whole feeling of the south is of being neglected,'' she said.