Regional authorities plan to launch a pilot project this year to help restore Beaver Lake, but time is ticking on the larger ecosystem.
Glenn Harris, senior manager of environmental protection, said the region risks losing the social and economic benefits of Elk/Beaver Lake Regional Park without efforts to improve water quality.
“Overall, water quality in the lakes is declining and with cyanobacterial [blue-green algae] blooms increasing in frequency and duration in Elk and Beaver Lakes, the risk to health of humans and pets and park use is rising,” said Harris.
He made these comments in a report to the CRD’s regional parks committee meeting. The CRD last year hired temporary staff to co-ordinate and develop a remediation strategy and to establish a watershed management plan with three goals: reduce blue-algae blooms, improve fish habitat, and manage weed growth to improve recreational use.
The CRD also tasked staff to investigate the installation of an oxygenation system for Beaver Lake and to develop a business case for the remediation Elk Lake. To this end, staff plan to implement a pilot aeration system this summer near the Rowing Centre on Elk Lake.
The project will test whether aeration — the addition of oxygen — can control algae blooms and whether it is feasible for Beaver Lake.
While connected, Elk and Beaver function as separate systems because of their different sizes. This means remediation measures for Elk Lake will have little impact on Beaver Lake. Each lake will require its own approach. Beaver Lake was once a shallow, submerged wetland. Significant amount of organic matter overlay its lake sediments. Elk Lake is a bigger, deeper lake. But both lakes are subject to seasonal blue-green algae blooms often at different times of the year.
“These blooms of naturally-occurring bacteria have the potential to release cyanotoxins into the water, which are hazardous to people and pets that ingest the water,” said Harris.
Phosphorous bears responsibility for the blooms. During the summer, lake-bottom sediments release phosphorous, which the oxygen-deprived lower water level traps. Once the temperature of the higher water levels has dropped, the phosphorous can rise to the top, where it becomes available for use by blue-green algae. “This results in sudden population growth or “blooms” of blue-green algae and greatly increases the potential for the production of cyanotoxins,” he said.
They turn in threaten an ecological, but also economic asset. Elk / Beaver Lake Regional Park ranks as most-used park in the region, generating 1.5 million visits. The lakes also are home to Rowing Canada, the national rowing team, and the national triathlon team and related events. “These activities can bring significant economic contributions to the region,” said Harris.
They include the Subaru Ironman 70.3 that draws some 1,600 competitors to the region every summer, generating an estimated $5 million in economic value to the region.
“The park also hosts many community events, day camps and nature programs that educate and benefit citizens year-round,” he said. “The swimming beaches in the park are extensively used by the public throughout the year, especially in the summer months.”
But extended blue-green algae blooms in 2016 and 2017 led to a spike of beach closures and cancellation of park programs, community festivals and sporting events.
An intergovernmental stakeholder group formed in 2015 that includes the District of Saanich and a stakeholder group that includes recreational users have been working towards solutions.
Various efforts have started to pay off and the CRD plans to a present its business case for remediation this fall. It might not be cheap.
“The lake system is complex and will likely require a multi-pronged approach to remediation and long-term management,” he said.
But if so, the issue is also pressing. “Overall water quality in the lakes is declining and with cyanobacterial blooms increasing in frequency and duration in Elk and Beaver Lakes, the risk to health of humans and pets and park use is rising,” he said.