The 16-mile multi-use Lake to Sound Trail is being built in segments and will ultimately span from the south end of Lake Washington to the shoreline of Puget Sound. It offers a non-motorized transportation alternative to South King County and strengthens regional trail connections between communities, making it convenient to walk, run, or bike and connect to high-capacity transit. The trail is typically 12 feet of pavement with 2-foot shoulders.

Parametrix completed a feasibility study and evaluated alternative alignments for the trail, considering environmental impacts, existing right-of-way, connections to local communities, and planning level cost estimates. We helped prepare successful federal transportation grant applications and have subsequently completed design, permitting, and construction services for the various segments.

Segment A is 1.1 miles, from Fort Dent Park in Tukwila to the Black River Riparian Forest in Renton, where users can catch glimpses of the largest heron rookeries in the region. The trail crosses over the Black River via a new pedestrian bridge, traverses under high-speed rail, and includes a new HAWK pedestrian signal that allows users to cross a heavily traveled industrial road.

Segment B is 1.5 miles connecting SeaTac and Burien along Des Moines Memorial Drive. The design includes a boardwalk over Walker Creek and associated wetlands. Parametrix negotiated lease agreement and construction approvals from WSDOT for traversing under SR 509, and coordinated with Seattle City Light for the undergrounding of utilities.

Segment C connects Segment B to the Des Moines Creek Trail. It traverses a densely developed area requiring coordination with a number of stakeholders, including WSDOT for use of a portion of the right-of-way intended for an extension of SR 509, as well as the cities of Burien, Normandy Park, and SeaTac. Other portions of this segment traverse forested natural areas, including a segment of boardwalk that crosses a stream and associated wetlands.