• Working in or near private right-of-ways is another major cost risk factor for seemingly straightforward projects like trail creation.

    Credit: King County Dept. of Natural Resources and Parks

    Working in or near private right-of-ways is another major cost risk factor for seemingly straightforward projects like trail creation.

Most people wouldn’t consider building a trail particularly risky. But like any project there are inherent challenges that, if not addressed, will slow construction and increase costs.

East Lake Sammamish Trail was selected as a high-risk project in 2010, the year the King County, Wash.,auditor’s office launched the Capital Project Risk Scoring Instrument.

Designed to complete a 44-mile link in a regional trail system, an existing bicycle and pedestrian trail is being built and/or widened along 11 miles of former railroad corridor. The $68 million to $72 million alternative transportation project provides access to recreation, employment, and retail centers in the cities of Issaquah, Redmond, and Sammamish.

Risk scoring identified several design challenges.

1) All along the trail corridor, homeowners had built driveways, stairs, retaining walls, fences, and landscaping close to the existing trail and many times on the county’s right-of-way. Many driveways and/or roads to these homes are steep and don’t meet code. Currently, the trail is 8 to 10 feet wide; the master plan trail is 18 feet. This will require the design engineer to look at and design each one of these conditions individually.

2) The former railroad bed elevation is high. The trail will reduce the height of the former railroad bed and make the trail footprint wider, necessitating fill and/or retaining walls.

3) Much of the trail is surrounded by wetlands, so the trail must be designed to reduce environmental impacts.

4) Space for construction is limited and there’s limited access for construction equipment.

These and other considerations earned the project a 189. The auditor’s office calculates the average score of all county projects as 212, compared to the 256 average score of those projects selected as high risk.

Typical of all selected, high-risk projects, this project is subject to mandatory phased funding, specific risk management protocols and quarterly construction reporting.

“I’m happy to say the project appears to be on the trail for success,” says King County Capital Projects Oversight Manager Tina Rogers, PE, who developed the evaluation system.