Beneath the Surface: What's going on in Beacon Hill Park lakes

By Janis Ringuette

Goodacre Lake Bridge

Weeping willows overhang the water, lily pads decorate the surface, ducks paddle serenely, turtles sun themselves. The lakes of Beacon Hill Park appear idyllic. To keep them that way, a major commitment by the city is necessary.

Poor water quality is an ongoing problem. All Park lakes are artificial. No natural spring or stream flows in and no stream flows out. Large quantities of leaves fall in steadily from overhanging bushes and trees and blow in from surrounding vegetation. There are copious additions of duck feces, dust, pollen, seeds, insects, feathers, bread, plus the occasional shoe, pop can, and dead rat. Sediment builds up.

The Goodacre Lake system

There are two completely separate lake systems in Beacon Hill Park with very different water quality challenges and solutions.

The largest recirculating lake system includes Goodacre Lake (by far the biggest at 2.43 acres), Fountain Lake and Arbour Lake. Park staff adds only enough water to equalize loss from evaporation.  No water goes out unless heavy winter rains overfill the lake causing overflow to spill into a storm drain by Arbutus Way.

Rampant algae was a major problem in Goodacre Lake from 1995 through 2005. Algae absorbs oxygen and as it decays, further reduces oxygen levels. Algae severely affects aquatic life and is very ugly. There was a dramatic change in 2006 when the dominant vegetation in Goodacre Lake changed to Elodia (Elodea canadensis). Also known as Canadian waterweed or Canadian pondweed, Elodia is a much healthier and preferable pond vegetation. In Spring, 2007, algae turned the lake water putrid green again, but by April 30 Elodea was visible in deeper water by the Stone Bridge; it increased steadily--while algae decreased--until Elodea was dominant in August. Ten years of concerted effort by the city to improve water quality had paid off at last. An aeration system to increase oxygen content--including underwater pumps, bubbler lines and three floating fountains--runs twenty-four hours a day. Many tubs of beneficial bacteria were added to the lake to consume algae and sediment. Calcium and pH levels are tested regularly and some sediment was removed manually.

Goodacre Lake attracts Mallards, Wigeons, Canada Geese, Great Blue Herons, Hooded Merganzers, as well as the occasional Kingfisher, Scaup and River Otter. The small fish in Goodacre Lake are called Pumpkinseeds (Lipomis gibbosus). Up to thirty-four Red-eared Slider turtles have been counted on sunny days. There are small crayfish in both Goodacre and Fountain Lakes.

The Goodacre/Fountain Lake system has the potential to be balanced and healthy because there is a good volume of water and because both lakes have soil bottoms and growing plants. Lily pads cover most of the surface of Fountain Lake and these plants provide needed shade for the water. (Arbour Lake contributes nothing to water quality. It is a shallow basin with a concrete bottom.)

The Circle Drive Lake System

The second lake system is a different story. Four small lakes--Queens Lake, Willow Lake, Deer Lake and Rose Lake--are situated along Circle Drive across from the Children's Farm. They are all very shallow (about 18 inches deep) and have concrete bottoms.

Rose Lake
Rose Lake - Photo: N. Ringuette, July 4, 2004.

For more than twenty years, Park staff regularly emptied dirty water from these "lakes" into the storm drain, hosed down the concrete and refilled with fresh water. (This is how Harrison Yacht Pond has been cleaned since it was installed in 1955 and how the Kiwanis wading pool was cleaned from 1925 until it became a constantly draining spray facility in 2002.) CRD regulations now prohibit draining lake water into the storm drain and park staff can no longer easily empty the water and clean the concrete. They tried emptying the ponds by running a fire hose from the ponds east across the road, pumping water and sediment onto the field south of the cricket pitch. That allowed them to clean and refill the ponds with fresh water but was time-consuming and made a mess on the meadow. With no other plan in place, the same green water remains month after month as the sun beats down, leaves and debris accumulate, and ducks defecate.

[Updated November, 2007.]