Sustainable Trail Building Techniques for Mountain

Bike Trails

The Half Rule

Ensure the grade of the trail doesn’t

exceed half the side slope. Otherwise

water will flow down the trail and not

across it resulting in erosion.Water is the enemy of all trails

The 10% Grade

Average

An average grade for the trail of below 10% is the

most sustainable.This may not be achievable

throughout the trail but it is important to use this as the baseline for construction

Grade Reversal

Periodic Grade reversals ensure that water is not

trapped on the trail and flows slowly of the edge and not down the fall-line

Outslope

An outsloped trails ensures that the

water drains gently in a non erosive

manner via “ sheet flow”

Knicks

Like grade reversals and

de-berming trails these allow water to escape slowly from the side of the trail. These

can add in a trail feature for riders

Rolling Grade Dips

These are larger

features than Knicks and provide consistent

drainage on up slopes

and climbs

Climbing Turns

These allow controlled climbs on

steep slopes without the

erosion associated

with a direct climb

Rolling Crown Switch Back

This requires a more advanced

approach by using retaining walls but allows sustainable

construction in upland situations

where high rainfall

is present

Insloped Turns

• These are excellent for descents where you want retain flow and fun without causing braking. Grade reversals and a semi-banked turns help to reduce erosion via sheet flow.