After the last log is loaded and the equipment leaves, skid trails often remain as the most visible mark on a woodlot. These compacted pathways act like channels, concentrating rainfall and sending it downhill fast enough to carve gullies, undermine roots, and wash sediment into nearby streams. Installing water bars is the simplest, cheapest way to prevent this damage. A water bar is nothing more than a shallow ditch or berm laid across the trail at an angle, designed to intercept runoff and spill it onto stable ground before it can pick up speed.
When and Where to Place Them
Spacing depends on slope. On gentle ground with less than five percent grade, one water bar every hundred feet is usually enough. As slope increases, tighten the spacing. On grades steeper than fifteen percent, place them every fifty feet. Each bar should cross the trail at roughly thirty to forty-five degrees, pointing downslope so water follows the angle instead of punching straight through.
The outfall—the place where water leaves the bar—matters just as much as the bar itself. Always direct flow into undisturbed vegetation, a broad flat area, or a stable ditch. Never dump water onto another skid trail, a landing, or a stream channel. If the slope continues below the trail, make sure the outfall is far enough from the edge to prevent the toe of the slope from collapsing.
Types of Water Bars
There are two common styles suited to small-scale operations. Choose based on the tools you have and how permanent the fix needs to be.
- Rolling dip or cross-ditch: A shallow trench dug across the trail with the spoil piled on the downhill side to form a low berm. This style drains quickly and works well on trails that will see occasional future use.
- Berm or mound: A ridge of compacted soil, rocks, or brush built across the path without a deep trench. This is faster to build and fine for trails you plan to close completely, though it may need more frequent maintenance.
Building a Cross-Ditch Water Bar
If you have a shovel and a rake, you have enough equipment. Start by marking a line thirty to forty-five degrees across the trail. Dig a trench twelve to eighteen inches wide and six to eight inches deep along that line. The upslope side of the trench should be vertical or nearly so; the downslope side should taper gradually. Pile the excavated soil on the downhill edge and pack it lightly to form a berm. The top of the berm should sit a couple of inches lower than the original trail surface so water enters the ditch rather than skipping over it.
Once the bar is shaped, seed the disturbed soil with a fast-germinating grass or a native erosion-control mix. Cover the seed with straw mulch. Vegetation is what ultimately holds the structure together through heavy rains.
Mistakes to Avoid
- Running bars perpendicular to the trail: Water hits the berm head-on, builds pressure, and blows out the structure. Always keep the angled orientation.
- Too shallow or too narrow: If the trench cannot handle the peak flow from a thunderstorm, it will overtop and erode.
- Directing flow onto unstable ground: An outfall on bare soil or a steep bank will simply move the erosion problem downhill.
- Using rotten logs as berms: While a log seems convenient, it decays and leaves a gap that funnels water exactly where you do not want it.
Maintenance and Long-Term Care
Water bars are not a build-and-forget solution. Inspect them after the first hard rain and again after the spring thaw. Look for rills cutting around the ends, sediment filling the trench, or mulch washed away. A quick ten minutes with a shovel is usually enough to restore function. If the trail is being retired, consider broadening the water bars into a full trail decommissioning by ripping the compacted surface and planting shrubs.
Taking a single afternoon to install proper drainage can save years of soil loss and keep your woodlot in working condition for the next harvest. Water bars are low-tech, but in sustainable forestry, simple tools used well often outperform expensive fixes used poorly.