Hiker's bridge

 

Bridge Creek Foot Bridge Design 
The Bend/Fort Rock Trails program proposes to construct a 28’ single-log “Standard Foot Log Trail Bridge” across Bridge Creek on the Swampy Lakes Trail, approximately one mile upstream from the Tumalo Falls trailhead. This proposed design was developed for a variety of applications by Dave Nordenson, Willamette National Forest bridge engineer and has been signed by the Willamette Forest Engineer, per his authority to approve bridge designs for structures under 50’. This design has long been in use for bridges on the heavily-used McKenzie River Trail and is currently being utilized for new bridges in appropriate circumstances on the Willamette. It is similar to bridges found throughout the Deschutes. We believe that such a rustic design is most compatible with the Bridge Creek bridge setting for a variety of reasons.

The proposed bridge site is located in the City of Bend Watershed, approximately one mile above the drinking water intake. This area is closed to all stock, bicycles, and dogs, allowing hikers only, to protect water quality. The city and Forest Service discourage use through minimal trail maintenance, requiring self-issue permits, and prohibition of camping. This crossing is on a segment of trail that is the least used in a little used area. The more commonly used segment between Bridge Creek and Happy Valley has never had a bridge across the upper Middle Fork of Tumalo Creek. When the previous log bridge at this Bridge Creek crossing failed several years ago, it was decided not to replace the bridge and allow hikers to use a fallen log. However, because of the greater depth and velocity of Bridge Creek, it was decided to propose construction of a new bridge. Threaten mollusks may be protected by a bridge as well.

The watershed area is designated “Semi-Primitive, Non-Motorized” (SPNM) in the Deschutes Forest Plan. On the USFS “Recreation Opportunity Spectrum” poster, SPNM calls for “Rustic and rudimentary facilities primarily for site protection. No evidence of synthetic materials. Use undimensioned native materials.” The closest foot bridges on the South Fork and lower Middle Fork of Tumalo Creek are such simple structures.

In summary, for the following reasons we propose a “Standard Foot Log Trail Bridge” 
1) To provide a design consistent with “Semi-Primitive Non-Motorized”.
2) To prevent potential contamination of Bend drinking water from leaching chemically treated material.
3) To insure a consistent design with surrounding bridges. 
4) Bend/Fort Rock trails staff believe it is just the right thing to do in this location for such a small bridge in a little-used hiker-only setting. Anything more is over-kill in time, design, and cost.