City of Kenmore, Washington - City Projects: Swamp Creek Project

Project Status Report

Swamp Creek Flood Reduction Projects

Location:

Swamp Creek, along 73^rd Avenue NE, between NE 185^th Street to NE 192^nd Street

Background:

In 2001, King County provided $10.75 million through a Memorandum of Agreement (MOA) to the City of Kenmore for the design and construction of flood reduction improvements in the Swamp Creek watershed, to mitigate for the impacts of constructing King County Metro sanitary sewer projects in Kenmore. The MOA between the City and King County requires that these funds be used for specific flood reduction projects identified in the 1997 Swamp Creek Action Plan (King County, 1997). The City’s design consultant for both phases is Otak, Inc.

The purpose of the Swamp Creek Flood Reduction Improvement Project is to reduce flooding in the Swamp Creek basin within the City of Kenmore. The improvements will eliminate or reduce flooding for approximately 15 to 20 properties, return Swamp Creek to a more natural condition, prevent flooding of King County Metro’s sanitary sewer trunk line, and reconstruct a portion of 73^rd Avenue to its current minor arterial standards.

Status:

Phase 1

Phase 1 improvements were completed in 2005-2006. The Phase 1 improvements included the following elements:

· Replacing the 73^rd Avenue Bridge over Swamp Creek.

· Raising approximately 700 feet of 73^rd Avenue NE north of the Swamp Creek bridge to meet the new bridge elevation, and bringing the street up to current standards for a minor arterial.

· Reconstructing the secondary access street to Kenmore Elementary School to serve as a flood control levee. A sidewalk will also be added to the north side of the street to improve pedestrian safety.

· Realigning the Swamp Creek channel upstream and downstream of the bridge.

· Creating a floodplain wetland upstream of the bridge to increase flood storage capacity.

· Constructing a woody debris jam along Swamp Creek upstream of the Wallace Park Sediment Pond to prevent the creek from jumping banks during high flows.

Phase 2

The Phase 2 improvements on 73rd Ave were completed in 2005-2006.. This phase covers the following improvements:

· The Wallace Park Sediment Pond improvements will be constructed during summer 2006.

Extend the Phase 1 street construction approximately 1,100 feet south of the Swamp Creek bridge and elevate the street on average 18 inches to protect against future flooding.

· Provide mitigation to four homes east of 73^rd Avenue NE that may be impacted by a slight rise in the proposed 100 year flood elevation.

· Reconfigure the Wallace Park Sediment Pond to better regulate the passage of sediment through Swamp Creek and establish an approved sediment removal protocol. Where possible, enhance the habitat features through the project area.

Staff Contact:

Rob English, City Engineer

Office (425) 398-8900; Fax (425) 481-3236

e-mail: renglish@ci.kenmore.wa.us