Deere & Ault Consultants, Inc. staff prepared the final engineering design, specification preparation, and services during construction for improvements to the secondary fish separator screens, the counting house, and the juvenile fish bypass facilities at Tacoma Power’s Mayfield Dam.
Mayfield Intake – The Secondary Fish Screens are a 250 cfs capacity Vee arrangement using stainless steel woven wire
for the screens. Modification to the screens included the design of a series of 180 degree adjustable louvers and an
innovative cleaning mechanism with a flotation boom which could operate in a very restrictive physical space.
A new counting house facility was designed to attach to the existing fish separator and raceways which included parallel fish counting and tagging trains with chutes for sorting, anesthetic baths, tagging equipment, and recovery tanks. A lift mechanism carries the tagged fish up and over the top of the counting facility and delivers the fish to the flume leading to the transport pipeline.
In addition, the pipeline from the counting house to downstream of the tailrace required significant rehabilitation, which included the recabling and replacement of joints and protective coating for a 460 ft suspension bridge carrying a fiberglass reinforced plastic pipe. The portion of the pipeline running down a steep slope was slip-lined with HDPE pipe, with a new expansion coupling installed at the upstream end.
Client: Tacoma Power
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