There are many aspects of trail design that combine to create a smooth-flowing, appealing, and sustainable trail, and where implemented successfully, these should result in minimum impact. Such technicalities include the location, slope, drainage, and soil type, which make the trail a great experience for the rider without damaging the surrounding environment. Design principles are the standards and guidelines which involve technical considerations for the planning and building of trails. The key principles for designing sustainable mountain bike trails focus on water drainage, trail grades, and minimising soil loss. A sustainably designed trail “limits both trail degradation and annual maintenance while accommodating intended amount and type of use.” (Marion and Wimpey).
Control points to be aware of along trails (Recreation SA, 2016)
Approximately, only one-third of trail erosion results from the use of trails by riders, the majority is caused by rainfall, runoff, terrain, soil texture, and vegetation cover (interacting factors). If erosion is not addressed, it can lead to secondary impacts such as reduced water quality. Design principles, including slope alignment and assessment of soil characteristics, aim at minimising loss of soil from erosion and water runoff. Tread armouring, berms (banked turns), and out-sloping are features to manage major soil displacement from the elements. Whereas, erosion from trail use can be prevented by regulating grades and following contours to control rider-speed and the need for braking.
In general, sustainably designed trails best minimise degradation where trails are located at mid-slope with moderate side slopes, have low trail grades (<10%), and follow the topography contours.
Photo courtesy City of Albany