David Evans and Associates, Inc.: Fanno Creek Trail Improvements Project

 

EXECUTIVE SUMMARY

The Fanno Creek Trail is a regional multi-use trail located within the cities of Beaverton and Tigard, Oregon. As result of successful habitat improvements along the creek, beavers have recolonized the area, which has, in turn, led to flooding along various trail sections. The project includes a 160-foot-long trail section parallel to the creek underneath the Scholls Ferry Road bridge, at the boundary of Beaverton and Tigard. This area includes park land owned and maintained by Tigard and the Tualatin Hills Park & Recreation District (THPRD).

The Fanno Creek Trail Improvement Project, led by Clean Water Services (CWS), with Tigard and THPRD as partners, sought to reduce the frequency of flooding at this short trail section under the bridge. The project serves as an interim solution by raising the existing trail by several inches until a planned at-grade crossing can be constructed in the future. This project presented multiple challenges that the David Evans and Associates, Inc. (DEA) team worked through closely with CWS staff. These challenges included receiving no bids the first time around in part due to pandemic-related constraints, which delayed construction for a year; bids that were too high due to inflation, resulting in CWS field staff taking on the construction themselves; challenging construction conditions due to very low overhead clearance; and shifting the staging area into a wetland because the previous location was being occupied by a major infrastructure project. Design challenges included elevating the trail while still achieving a modeled no net rise for the creek. Permitting challenges included the project occurring in multiple jurisdictions (Beaverton, Tigard, and Washington County right of way) and, as previously mentioned, the change in location of the staging area, which required late-in-the-game permit modifications.