Raising the height of the St. Mary Lake weir is required to ensure water supply, protect sensitive fish habitat and improve water quality, according to the manager of the North Salt Spring Waterworks District.

“It is our feeling that it would be better to do so sooner rather than later so that residents around the lake and other users such as swimmers, boaters and fishers can get used to a new ‘permanent’ regime,” wrote Trevor Hutton in a letter sent to lakeside property owners.

The NSSWD proposes to raise the weir’s crest elevation to 41 metres from 40.7 metres.

The weir was constructed only three years ago to better regulate lake water levels.

Hutton said the district needs permission from the province’s Ministry of Environment to obtain a new water licence and conduct the work.

As of Monday, the water district had received one letter that indicated concern about the proposal.

The letter’s author, a Bradbury Road resident, wants the district to gather more public input and produce more information about the proposed change’s impact on lakeside vegetation, septic fields and water quality.

Hutton said the district’s September letter to property owners was the first stage of the input gathering process. Discussion, he added, will focus on the 81 property owners who reside near the lake.

“We have not ruled out a public meeting,” he said. “It all depends on what kind of response we get from property owners.”

As part of the licence application, the water district must provide the province with an updated island population projection study through to 2030.

“The ‘demand’ for water from St. Mary Lake is increasing as Salt Spring Island develops and the supply is likely to become more erratic as a result of global warming,” Hutton wrote.

Historical data reveals that yearly peak water levels have decreased since the weir was built in 2006.

A study conducted for the water district by biologist Kathy Reimer determined that keeping the lake water close to the historic 41-metre level “will best protect the lakeshore vegetation and the important associated fish habitat.”