Tip # 12: Pigs Love Mud Holes...

But trail users don’t. If you need to fill a hole in the trail, first get any water out. Then fill the hole with damp dirt, not wet dirt. Layer the fill in stages and pack each layer so that the fill compresses. Filling ruts and holes in the dry season is not very effective, as the fill will not stay in place.

For a great series of documents about trail building and maintenance, check out the IMBA (International Mountain Bike Association) site. www.imba.com/resources/trail_building/index.html