The bridge project at Liberty Lake Park – Cedar Grove [ Six days ]
Here is a photo-rich and text-deficient report of a project of Washington Trails Association (with Spokane County Parks support) in far eastern Washington. This site is about 1/3 of a mile from the WA/ID boundary line.
Many of the photos were taken by volunteer Belinda Cron, with some by John Hultquist. Sorry if I miss others, but thanks Belinda.
The project was directed by Alan Carter Mortimer, WTA Seattle. Spokane area crew leaders were Holly Weiler and Jane Baker.
Photo #1: Existing CrossingThe trail comes downhill on the far side – shown by orange dots – and crosses to the near side on a well aged bridge. The orange arrow points to a fallen tree, used as a support. Being late September, after a dry summer, the stream is low – just a few inches deep. Stream bed is just 18 inches below the log.
Photo #2: Concept sketch
The concept is to replace the old bridge (left) with a 2-log flat walking surface, with a handrail on the up-stream side. The new structure will be about 6 feet above the stream bed. The design will accommodate those riding bicycles.
Photo #3: Measure
The supports for the two ends are being located, then digging can begin. There are tree branches and downed material still in the work area.
Photo #4: Platform started, rocks gathered
Looks like lunch time. Note the pile of rocks. Gatherers are taking a break in the background. The four folks in the foreground are well on the way to having the near-side platform dug.
Photo #5: Gabion constructed
Orange dots show the location of the trail. Note the right-most dot is at the place where someone in a blue shirt is hiking.
The center of this image shows a wire basket-like structure filled with rocks. This is a Gabion; LINK.
Photo #6: Near side Gabion
On the near side, the Gabion is ready for filling. Rocks need to be larger than the holes. The edges are held together with a metal spiral, much like that used on some note books.
Photo #7: Sill placement
The gabion is a foundation but not the best thing to connect the logs to. Wood sills do this job. These could have been formed from trees. The County Parks folks chose cut-in-a-mill sills.
Under the rocks a metal bar/plate anchors 2 long steel rods. These are threaded on the top end. Note the orange oval on the right, and the second rod top just to the left of the yellow level.
Photo #8: The logs
Two trees were cut on the slope in the distance. They were brought off the hill and the bark removed. In spring, inner bark (phloem) is soft and wet. This can be peeled easily, but does vary. In fall, the bark holds more tightly and the thick outer material requires more work to get it off. Thick, old, bark from close to the ground is no fun at all.
Bark holds water and becomes a habitat for critters that damage wood. That’s why we take it off. I like to use a sharp axe on the tougher parts. “Draw knives” can be used, but are better on the thinner bark.
Photo #9: One log peeled, another to go.
Over several hours there were crew changes, as we went off to do some other things.
Photo #10: Topping the log
The three green lines indicate cuts across the top of the log. Deciding what the top is, and marking how deep the cuts will be, is time consuming, but not physically demanding.
The red oval shows chunks that have been knocked off the log. There is much of this material. It gets cleaned up and dispersed off in the forest.
Photo #11: After the saw makes parallel cuts
Getting the top off requires work. There are several techniques.
The young lady on top of the log is using an adze (adz) LINK to adze This very ancient tool is in the hands of a soon-to-be highly skilled medical doctor. How cool is that!
We showed her how and she got busy. I used an ax. Two others used 2″ wide chisels and hammers. After a time, it got crowded with safety becoming and issue. I left this task and worked elsewhere.
Photo #12: Laying out equipment
We have just retrieved tools from a cache up the slope. The folks lined up pass a tool down to the next, and the next; a human chain or brigade. Important equipment in the foreground are grip hoists and wire rope (cable).
That’s all for now. We’ve got 2 big logs to move. Later! John