Baseline environmental studies of Ruth Lake and Poplar Creek

• Main Author: Syncrude Canada Ltd.
• Format: Other/Unknown Material
• Language: English
• Published: 1975
• Subjects: envir; geo; Athabasca River; Minnows
• Online Access: https://doi.org/10.7939/R3BV79W70; https://era.library.ualberta.ca/items/2875041a-0c11-466d-b35d-66ba08549b14

Factors involved in the ecology of Ruth Lake and Poplar Creek are discussed. Ruth Lake is a small, littoral, moderately eutrophic lake. It has clear water, a muddy substrate, and is shallow (mean depth 1.5m). Winter stagnation /occurred but the water was well oxygenated in summer. Phytoplankton populations were moderate (3,000-6,000 cells/ml), relatively constant through the summer, and dominated by small and motile algae. Macrophytes were found at all points in the lake and Nuphar variegatum (lily pads) was very abundant where the water was 2 meters deep or more. Benthic invertebrates (3,000-9,000/m2) were dominated by chironomidae larvae. Zooplankton were most abundant numerically in late May and averaged 20,000/m3 over the summer. This community was typical of a moderately eutrophic pond. Probably because of low winter oxygen levels, brook sticklebacks and fathead minnows were the only fish found in the lake. Poplar Creek is a small, brownwater tributary of the Athabasca River. Oxygen concentrations in the creek were always greater than 8 ppm, the stream pH was near 8.0, and the total dissolved solids and chloride levels were highest in winter. Tar sand is common in much of the substrate. Benthic invertebrates were more diverse and abundant (about 250/2ft2) on rubble substrates than in sand/silt bottoms (about 30/2 ft2). Populations were lowest in May and highest in August-September, and dominated by clean water organisms (mayflies, stoneflies, caddisflies) in rubble substrates. The stream is slower, deeper, and wider with a sand/silt substrate below the proposed spillway. Above the spillway, a higher gradient occurs with more gravel/rubble riffles. A small resident, reproducing population of grayling in the upper section, and of suckers in both sections, is indicated.