Project: City of Roslyn Pennsylvania Place Bottleneck & SW Treatment Retrofits

Bid Date: Tuesday, July 18th, 2023 @ 2:00pm

Pacific Civil & Infrastructure, Inc. is seeking proposals from qualified and certified DBE Subcontracting, Supplier and Equipment firms for various scopes of work including Trucking, Erosion Control, Hydroseeding, Fencing (split rail), Reinforcing Steel, Asphalt Saw Cutting, Traffic Control, and Survey.

The Project’s Scope of Work as described in the Invitation to Bid is:

A high-flow bypass stormwater pipe running along Coal Mines Trail to alleviate capacity concerns within the City storm drain system between East Pennsylvania Avenue and East Washington Avenue as identified in the City of Roslyn Stormwater Comprehensive Plan, July 2014, Gray & Osborne, Inc. (SCP). This bypass will route excess flows directly to Crystal Creek, beginning at East Washington Avenue and following the Coal Mines Trail eastward and then southeastward for approximately 1,660 feet. The undersized pipe in the existing trunk line will remain in place, conveying all low-flows and baseflows along the original route. The proposed bypass begins with a 7’ x 9.5’ x 14.5’ cast-in-place concrete box structure with spring-assisted access hatch. The bypass structure contains an overflow weir that diverts high flows into a 36” HDPE pipe that travels 412’ in length before transitioning to a 42” HDPE pipe for 1,286’. This pipe outfalls into a proposed ditch that has riprap lining for 23’, then streambed cobble mix for 30’ before outfalling into Crystal Creek. A small portion of the existing stream bank will be re-graded to provide an appropriate transition between the outfall ditch and Crystal Creek. The project also includes interception of an 8” storm drain where it intersects the bypass alignment, paving, replacement of gravel pathway along the pipe alignment, plantings, and installation of a split-rail fence and hand-placed boulders separating the existing path from the outfall ditch.

Stormwater treatment retrofits consisting of biofiltration swales to improve water quality within the local waterway, Crystal Creek. The City currently has limited Best Management Practices (BMPs) within the urbanized areas of the City. The BMPs will provide stormwater runoff treatment for the reduction of Total Suspended Solids (TSS) and other pollutants. Nine biofiltration swales will be constructed on Utah Avenue, 1st Street, A Street, Idaho Avenue, Washington Avenue, and the intersection of Pennsylvania Avenue and B Street. The outfalls from each biofiltration swale will be connected to the existing stormwater conveyance network. The connections to the existing stormwater conveyance network will be made using CPEP pipe, ranging from 6” to 15” in diameter. There will be approximately 560 linear feet of pipe required to connect the biofiltration swales to the existing stormwater conveyance network.

Obtaining plans and contract documents:

Contract Documents are available via the City of Roslyn’s website: https://www.ci.roslyn.wa.us/departments/public-works.php

Pacific Civil & Infrastructure, Inc. is an Equal Opportunity Employer.