Trail Design

Heil Valley Field Trip with trail builder Mike Rutter

-Built in 2000 using a 4ft wide bulldozer (Sweco) (pic in the back of the pdf that you were assigned to read)
-Sandstone quarried there was used to build CU buildings
-Heil experienced a very wet spring this year
-The water table was already high because of snow and spring rains. Additional water created random springs and water flowed on and through the trail
-Area is very rocky and sandy
-Leads to Erosion issues
-Volume and speed of water=greatest threat
-more volume=more ability to transport sediment
-more speed also = more ability to transport sediment
-Water cuts into the trails and carries sediment downhill (sometimes into riparian areas)
-Water also exposes the many rocks underneath the trail
-Solutions to Erosion
-Can be fixed by making the trail UAM
-Undulate and Meander
-Grade Reversals also a common solution to divert water off of the trail
-This method forces water off the trail.
-The use of pavers and road base helps
-Pavers cover the width of the trail
-Road base doesn’t erode as easily and absorbs water
-Box culvert- allows water to run underneath trail by using two bricks and a paver
-Create climbing turns for MTBers
-Slight uphill before and after turn keep rider’s speed down
-Riders do not need to slam on the brakes going into the turn
-One turn can take over a week to build
-Ditching
-used to catch water coming downhill towards the trail and diverts it over pavers, box culverts, etc
-The original trail has been rerouted to make it more sustainable
-Optimal grade between 6-8%
-Trails designed to “feel fast” for MTBers
-Because bikers are forced to constantly think and watch the trail for choke points, etc. the feel as if they are going fast, but in reality they are not going as fast as they think they are
-Trees were used on the Wild Turkey Trail near a climbing turn to keep hikers from cutting thru and creating an undesignated trail
-60% of trail users are MTBs (on the County Parks and Open Space)
-Horses have the greatest single impact on a trail, but only account for 3% of trail users

Study questions:
1. Describe a grade reversal and explain its purpose.
2. Why is it so critical to get water off the trail?
3. Why are trails outsloped and how much should a trail be outsloped (look this up in the pdf).
4. What type of rock is the substrate for the soils at Heil Valley Ranch?
5. What must trail designers consider in addition to technical trail qualities such as slope and grade reversals when they decide where a trail is going to be located?
6. Name 3 hand tools used for trail building and describe their uses (look this up in the pdf).
7. How steep is too steep for a sustainable trail?
8. What is the difference between paving and pitching?
9. Who feeds the bears?