Phoenix Dam is a historic water supply 3km northeast of Lawrence, constructed about 1863 for goldmine sluicing.
Clutha District Council deputy chief executive Jules Witt said the bypass had been a top priority following dam owner Port Blakely’s notification to decommission due to ongoing age-related safety concerns.
The flood protection work involved lowering the dam’s water level by 3 metres, between November 2023 and January this year.
"It is reassuring to have the bypass operational and working effectively.
"It has been providing the township with clear water at around 9 litres/second."
Mr Witt said the council was acutely aware that its Phoenix catchment water source would be insufficient to ensure continued supply to Lawrence. Alongside the bypass work, further work was under way to pipe water from Bungtown Creek.
The council sought approval from Heritage NZ before undertaking any works on the Bungtown race and siphon, as they were constructed before 1900.
This work had been split by two contractors responsible for the section from "the tunnel" (an archaeological feature within the race) and the upper section of the race.
"Observant locals may have noticed a helicopter at work in the area to lower around 200kg of pipework into the forest," Mr Witt said.
"We hope to have the Bungtown race operational, likely by mid-June, weather conditions permitting."
The bypass is a temporary solution until the new Greenfield bore, which will supply water from near the Clutha River, is operational and able to supply Lawrence.
The bore was under construction and involved a new water treatment plant, the amalgamation of pipe networks and 48.5km of pipeworks.
The present boil water notice in Lawrence related to a separate issue due to problems with water chlorination.
The council has lifted the stage 3 Water restrictions for Lawrence as winter approaches but asked residents to stay mindful of their water use and report any leaks.
