Broad-based Dips
Filed under: Ask Grant, Habitat Management
I am a hunter and landowner interested in the techniques that you have for stopping road erosion. Pat
Pat,
Road systems are one of the most important aspects of any property. In many cases they also require the most attention of all management activities. By installing a few structures these maintenance costs can be significantly reduced.
The main cause of road degradation is water movement. When water accumulates on a road surface and has no way of getting off it builds up momentum. This accumulation and momentum lifts gravel and other sediments and carries it down the hill. With this known the main goal of any road project is to get the water off the road surface as quickly as possible.
A system that works well is the creation of broad-based dips (BBD). A BBD forces water to run off and across a roadway while allowing smooth travel by vehicles. When determining placement of a BBD look for natural dips in the road that may need only minimal modifications to remove water from the road surface. Also, try to preplan where BBDs will be positioned before beginning. Generally, BBDs should be every 20 or 30 yards depending on slope. A BBD should be positioned at a 30-45 degree angle to the roadway. Start by removing soil from the uphill portion of the road and dumping on the lower portion until the dip is of sufficient depth to cause water to run off the road during all rainfall events. When creating the dip, slope the entire dip and 20 feet of the road above the dip, toward the edge of the road. The entire BBD will require a minimum of 30 feet to allow smooth travel of vehicles and equipment over the BBD surface. Rock may be placed on the outflow portion of the BBD to slow water and reduce erosion. Rock is not necessary if adequate vegetation is present after BBD completion. Once a BBD is completed use the entire surface of the road when traveling over it. By spreading the vehicle compaction and wear across the surface of the BBD, little maintenance will be required in the future.
BBDs are a great tool to stop erosion of roads. I use them extensively at The Proving Grounds.
Growing Deer together,
Grant