Performance of a coanda screen raw water intake on Norrish Creek

Description:Performance of a Coanda screen raw water intake on Norrish Creek. Presenter: Roderick MacLean, M.Sc., P. Eng. Associated Engineering. Additional Contributors: Brent Schmitt, P. Eng. Water Planning Engineer, City of Abbotsford. Norrish Creek is a major water source within the Fraser Valley Regional District, City of Mission, and City of Abbotsford. The City of Abbotsford operates a water treatment plant approximately 7 kilometers up Norrish Creek Forestry Road. The old intake to the facility was a constant operations and maintenance issues being prone to sedimentation, debris, fish entrapment and exposure to the creek’s large flow fluctuations. The City installed a new weir and Coanda screen intake upstream of the original. At this time, few, if any, Coanda screens have been used on a municipal system, but was a viable option to help the City meet all regulatory and operational requirements for water quality and fish exclusion. The new intake’s capacity is 141.5 ML/day, and slightly above the current capacity of the slow sand and newer membrane filtration systems in the water treatment plant. The project design was subjected to a complete Environmental Impact Assessment, and was monitored regularly by the Department of Fisheries and Oceans. The Coanda screens operations have significantly reduced the quantity of sediment, pine needles and turbidity of the intake water. Fish entrainment in the system has been eliminated, and frazil ice issues have been reduced significantly, but not completely eliminated. The authors will be presenting some of the interesting design and construction challenges involved in the project, and provide some updated results of raw water quality entering the water treatment facility following two years of operation.

Authors: Roderick MacLean

Subjects:

Tags:2015 Conference Presentations,2015 Annual Conference,AC15

Citation:Stream 2: Ensuring Water Quality & Supply

Publication Date:May 28th, 2015 Upload Date:Jun 25th, 2015

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