Buffalo Pound Water Treatment Plant Lake Intake ExpansionHydraulic Design and Water Quality Considerations

摘要

Buffalo Pound Lake (Lake) is a source of raw water supply for a number of municipal andindustrial users. The Lake, located in south central Saskatchewan is also a regional recreation destination.One of the largest water users on the Lake is the Buffalo Pound Water Treatment Plant (Plant), whichserves the Cities of Regina and Moose Jaw (Cities). The Plant has a capacity of 170 ML/day. Lake wateris conveyed to the Plant via a lake intake, pump station and raw water pipeline. The existing intake andCSP connecting conduit was constructed in the 1950's. Due to concerns for intake reliability and the needfor additional capacity, the Cities proposed to expand the intake capacity in 1999. This paper will presentthe design considerations, challenges and construction aspects associated with the intake expansion.Issues that will be discussed include:? Hydraulic design;? Water quality sampling, monitoring and assessment;? Environmental consideration;? Impact to existing works and construction challenges.As part of this study, an innovative raw water sampling system was developed for continuous monitoringof raw water quality. As the result of the site-specific study, the designer was able to substantially shortenthe lake intake without compromising the raw water quality. The final design included a 6.4 m × 6.4 mintake and a 1650 mm diameter concrete connecting pipe. The change in the intake design resulted in alarge reduction in capital cost and environmental impact. As part of the final design, alternativeconstruction methods were also assessed. The final construction method utilized to construct the intakewas an earth cofferdam and well point dewatering method. A system of floating siltation curtains wasutilized within the lake during the construction period to minimize lake water quality impact. The projectwas successfully completed in 2001/2002 with substantial cost saving to the Owners.