Standards and Procedures:
Locust Log Water Bars
Water bars have become something of a controversial structure within the trail building community. The USFS 2007 Trail Notebook notes: “Most waterbars are not installed at the correct angle, are too short, and don’t include a grade reversal. Poorly constructed and maintained waterbars become obstacles and disrupt the flow of the trail. The structure becomes a low hurdle for travelers, who walk around it, widening the trail.” The Notebook goes on to consider the fact that water bars clog easily, often cause problems for cyclists, and that horses can kick log water bars out of place. Finally, the Notebook suggests: “You can build a good rolling grade dip quicker than you can install a waterbar, and a rolling grade dip works better.”
So are water bars ever worth building? Yes, particularly on steeper slopes with over 15% grade, or where other site-specific conditions make a reinforced drain desirable. A modern water bar is ultimately just a reinforced drain, and in steeper spots, that reinforcement can help to stabilize a drain. Keep in mind though, that it is essential to build water bars properly. Otherwise, as the USFS notebook warns, they can cause more harm than good.
Black locust logs are a good, durable material to build water bars with. When material is available, it’s generally easier to build a log water bar than a rock water bar, since there is simply one unit that needs to be embedded in the soil. Keep in mind, though, that black locust is an extremely valuable and precious resource in our district and should only be used where it is truly needed. In many if not most cases, a regular drain will serve just as well as a water bar, so only use bars where the extra reinforcement is necessary.
In areas with abundantly available rock within the trail corridor, consider building a rock water bar instead, as rock will never rot and preserves precious black locust resources for other needs.
Below is a list of the essential items for building log water bars.
- Draw Knife (axe, pulaski, or even a shovel can also peel logs in a pinch)
- Chainsaw PPE
- Single-jack sledge hammer
- Pick mattock or other digging tools of choice
- McLeod - useful for finish work and tamping soil
- Shovel - useful for moving excavated soil
- Prospectors pick/mini-pick/rapid-digger - for digging in tight spaces
- Drag slings or log tong/carriers
- Buckets or canvas rock bags for transporting gravel/crush
- Tennis ball for testing drainage
- Use a single log if possible for the entire bar.
- Peel all bark from the log using a draw knife or other tool to provide greater rot-resistance.
- The log should be buried so the top is flush with the original tread surface. Minimize the amount of log protruding from the surface. The log merely reinforces a drain, and should not create an obstacle that trail users may avoid.
- Align the log at a 45 degree angle to the trail to facilitate water moving off the trail without losing speed. If water hits a sharp turn and slows down, it will deposit sediments and clog the drain more quickly.
- Keep the log level from side to side. One end of the bar shouldn’t be sticking up out of the ground.
- Extend the bar 12” into the backslope/bank. This prevents water and users from cutting around the side, and provides more stability.
- Fill empty space around the log with crushed rock. Pack tightly in place with hammers.
- Log should not wobble at all when stepped on. It should be virtually all beneath the surface. The log should not be in danger of being kicked out by a horse.
- Dig a wide (4ft or more), substantial drain (adhering to the principles in the Drainage section) just above the bar.
- The drain should ramp up to the bar. The low point of the drain should be several feet before the bar. Flowing water should never actually touch the structural bar.
- Aim to create a drain and water bar combination that is gradual enough that the average trail user won’t pay it much attention or even notice it.
- In most circumstances, stakes or rebar should not be necessary to keep the bar stabilized, if it is properly embedded in the soil.
These procedures are intended to provide a helpful reference guide to building log water bars, ensuring that you cover the essentials. If you are new to building this structure, it is best to learn hands-on from an experienced trail builder.
A. Survey the Site
1. Determine whether a water bar is needed or if a regular drain would suffice.
2. Is there locust available?
3. Determine the layout before you start building. Line out your angle.
B. Cut locust to length
1. Measure to ensure log spans the entire tread width at the proper angle, plus at least 12” into the bank.
2. Cut log to length.
C. Set Log
1. Dig a trench for the log, aiming for a precise fit with as little empty space as possible.
2. Set log, top flush with the tread surface, extending into bank.
3. Pack empty space with crush and mineral soil to stabilize.
D. Dig Drain
1. Start 2-3 feet uphill from the bar and dig a wide outlet.
2. Sculpt a ramp between the bar and the low point of the drain so that the log is barely exposed, if at all.
3. Sculpt a gradual ramp extending uphill, creating a wide, subtle drain.
4. Consider using a tennis ball to test the drain. The ball should roll smoothly down the trail and out the drain.
E. Finish Work
1. Tamp all soil thoroughly.
2. Revegetate work area.