Trail Work with Rocks:
An Uplifting Experience
10 July 2018
Intro: Why are we here?
• Part of a developing Trail Workshop Series by TKO
• Focus on developing TKO team expertise in Trail
• 8-10 person focus-teams with Rock Work
• Called into work parties for a specific rock work
• Some “classroom” discussion but 90% field
“hands on” learning
• Build trust with Land Managers and Staff
Many types of Rock work
• Protection for vulnerable trail sections: retaining
walls, creek crossings, soggy/wet areas.
• Only durable solution for heavy use soggy trail
sections (horse or heavy hiker usage)
• User protection from dangerous/risky areas.
• Aesthetic uses… guide and focal point rocks or
• Trail and structure durability and sustainability.
For instance, a properly completed rock retaining
wall will last for many decades compared to a log
Broad Classification of Rock Work
• Retaining Walls:
– Switchback walls (anchor and focal rocks)
– Upslope retaining wall, downslope tread support
– Guide or gargoyle rocks
– Soggy area tread support
– Hole fill -> tread support
– Seasonal creek swale and french drains
– Fords for small creeks
– Raised treads: turnpikes
• Rock Stairs: Attached and detached
• Rock Shaping: splitting, wedge/feathers, bushing
Ok…What’s in it for you?
• A different trail work experience. 50% a learned
skill, 50% art and aesthetics.
• A lot of exercise…..different than tread work.
• Team work essential. Women are welcome –
actually a safer rock team!
• Constant team communication necessary.
• Lots of skills: rock shopping, fitting, planting,
some shaping – a new vocabulary!
• Friends, fame, fortune…well, maybe not fortune.
• Learn the geology of the Pacific Northwest:
become a geology wonk!
(You, others near you, visitors)
• Always a JHA – “Jobsite Hazard Analysis” briefing
• “Never throw a rock away – always save it uphill”. You
will always need that rock…sometime
• “If you can lift a rock, it’s too small.”
• Anybody on the rock team can close the trail/work
section for safety reasons
• Trails team should always ask for permission to pass
through an active rock team section -> safety
• A runaway rock could ruin someone’s day -> “Rock
(You, others near you, visitors)
• “Brains first, muscles last”
• Remember that the two most common injuries in
rock work are pinched (or smashed) fingers, smashed
toes, and tweaked (or blown out) backs/knees. Both
sets of injuries are a result of using muscles first and
brains last. High-quality rock work is almost always a
methodical, even a tedious task. Safe work is ALWAYS
faster than taking time out for a trip to the infirmary.
Tools for the Rock Trade
• Lots of high-quality, high tensile strength steel rockbars.
• Pick mattock, grub hoe, rockbars are the primary work tools.
• Eye protection, gloves, and hardhat. Don't even think of
swinging a tool at a rock without wearing the required
personal protective equipment (PPE). Basalt rock often
splinters – think arrowheads!
• Rock nets, rock sling, straps—all useful for carrying rocks of
• Grip hoist and rope puller systems. Many rocks can be
dragged into place or removed from the trail.
• All sorts of equipment, including rock drills, wedge and
feathers, shaping hammers, chisels, and other tools. Lots of
Really nice trail rock…
• Initial new trail flagging:
2” of this rock showing
• After duffing, 8”
• “Ok…take it out…..”
• 2 hrs later, we have a
30” diameter and a
1200 lb rock!
• Now what????
for Moving Rocks
• Rock nets, web straps, two-person lift, grip
hoist, rope pullers, and choker(s) with block
• Skidding a rock safer than rolling a rock which
safer than lifting the rock
• Rock bar techniques: the Flip, the Pick and Pry,
the Waddle, the Row
• A runaway rock can be deadly!
Remember These 4 Guidelines
1. Bars and Hands, never the two should meet (on a
rock)! Only use one or the other when moving a rock,
never at the same time.
2. Communication! Especially when working with
someone to move a rock, use phrases like “Got it” to
let your partner know when things are steady and
ready to change. If you are working near the area but
not actively involved in the rock moving be aware of
your own blood bubble and theirs!
3. Always ask before helping. Do not assume someone
needs your help moving a rock.
4. Patience!! Slow and steady is safer
Goals for Building Rock
• “Simple is best” – Don’t over-engineer a solution
• Quality of Work vs Scope of work effort vs project
• Rock Team participates in the design of the structure
• Solutions dependent on the availability of “good”
Project Objective Tradeoffs
Quality of Work Scope of Work Effort
Competing Project Objectives:
• Quality of Work
• When complete
• Scope of Work Effort
Balance these Project objectives:
• Scenario 1: “Get it done ASAP”
• Scenario 2: “Make it last – Do it
• Scenario 3: Limit/size the work
effort (constrained by resources)
Be ready: These objectives will change during the project!
Retaining Wall Structures
• Complex, demanding work effort, and sophisticated
• Actual structure requirements are site specific
• Generally two to four layers of rock
• Will generally take several days to build
• Each rock is “fitted” – 50% of shopped rocks not usable
for wall -> backfill
• Foundation rocks, tie rocks, cap stones; backfill rocks
• Each wall rock is placed and “tested” for stability: min 3
points of contact
• Frontside shimming not allowed
• Harden the entry/exit of a small drainage
• Reinforce the tread mud pothole
• Rock turnpikes: tread is a soggy mess (McIver)
– Larger rocks for base, medium rocks as fill, crown with
• Rock as fill for holes or trail segments (the
“grave” at Augspurger)
• Raised tread: log turnpikes through a wet area
Switchback Rock Requirements
• Well-designed switchbacks are complex trail
• Can have several retaining walls based on site
• Tread slopes (in slope, out slope) change in the
• Hillside hydrology issues; drainage ditches often
• Use guide rocks to “steer” the user through the
1st Switchback: Angels Rest
Decades of cutting the switchback corner. Live roots badly damaged.
Washout: From the front From the top: 3 ft depth into tread
• USFS Trail Construction and Maintenance Notebook (2007 Edition). See
• Lightly on the Land: The SCA Trail Building and Maintenance Manual, 2005. Robert
• PCTA Trails Skills College Courses. See https://www.pcta.org/volunteer/trail-skills-
college/trail-skills-college-course-curriculum/ for Powerpoint, Word, and PDF
• Natural Surface Trails by Design, by Troy Scott Parker. (2004 Edition). NatureShape,
• Roadside Geology of Washington, by Marli B. Miller (2017 Edition). Mountain
Press Publishing, Missoula, MT
• Roadside Geology of Oregon, by Marli B. Milller (2014 Edition). Mountain Press
Publishing, Missoula, MT
• A new Geological Era?, Youtube TED talk by Johan Rockstrom: Let the environment
guide our development, https://www.youtube.com/watch?v=RgqtrlixYR4
Type Basic -A Advanced -B Complex -C
Upslope Wall Downslope Wall
Modernize or Repair New structure
Splitting; wedge &
• My email: