City invites experts to check effects of saltwater in Beacon Hill Park lake
Dec 29 2011
Beacon Hill Park’s lakes attract both people and wildlife. Salt in the system is not thought to be a serious problem.Photograph by: Arnold Lim, timescolonist.com
The City of Victoria wants to find out to what extent Beacon Hill Park's Goodacre Lake has been affected by saltwater-contaminated well water that was being used to top up the lake.
The city is advertising for proposals from consultants to analyze the lasting impact, if any, of the saltwater.
Goodacre is the largest of Beacon Hill's manmade lakes, on the park's western edge near Douglas Street.
For years, the lake was replenished with city water. In 2003, a well was dug and used to top up the lake during the dry summer months. But last year, it was noticed that the salinity in the lake had risen and was linked to the well water.
David Speed, Victoria's assistant director of parks, said the city has stopped using the well.
"We've used it in the past, mostly to top up the lake system. So we'd pump water out of the well and put it in the lake to keep the levels at the height we wanted," Speed said.
"But we found last year that there was quite a bit of saltwater getting into the well, so we've actually shut the well down."
Laboratory tests already undertaken show salt levels to be considerably below those considered to be dangerous for agricultural use.
According to the city's request for proposal, the selected contractor will evaluate the effects of the present salt levels, if any, on freshwater aquatic organisms associated with the Goodacre Lake system. The contractor will also determine an estimated threshold salt level that, when exceeded, would be harmful to freshwater organisms that are health indicators of the aquatic system.
"I think the concern is how much salinity have we gotten into the water in the lake system," Speed said. "We're concerned mostly about flora and fauna, any of the animals or any of the plants that would be freshwater plants."
Salt in the lake water system is not thought to be a serious problem at this time, he said. However, use of well water is thought to be behind the deaths of some fish last summer.
"We think the water is fresh in there but we've also had a problem with the recirculating pump system in the lake this year. That's a piece of aging infrastructure and we've just recently patched it back up where the system is back working."
Goodacre Lake dates back to the 1800s. For about 80 years, it was fed with fresh city water entering the system through the fountain at Fountain Lake and draining continuously out the northeast end of Goodacre.
In the early 1970s, a recirculation system was installed to save money. Ever since, water has been pumped from the bigger lake up to Fountain Lake, flowing back down the artificial stream in an continuous cycle.
Over the years, the city has battled algae problems exacerbated by feces from waterfowl overloading the water with nutrients. Since 2002, aerators have been used to increase oxygen levels and algae has not been as much of an issue, Speed said.
Small fish, including sunfish, live in the lake, attracting river otters and fish-eating birds.