To Drill or Trench?

When Jon Ersland purchased his first horizontal directional drill about 10 years ago, he figured he would use it only occasionally - likely just once or twice a week. But today, he finds he uses it much more often. "It goes out with us on just about every job," he notes. "With the changes we've been seeing [in this industry], it seems that we drill more and more. Now we tend to use the drill more than our trencher."

Ersland, his wife, Lori, and his son, Aaron, own/operate K & L Trenching, based in Huxley, IA.

K & L focuses on placing power, gas and phone lines. Tools in its underground equipment cache include a Ditch Witch JT921 horizontal directional drill and a 5110 combination trencher/plow. A Ditch Witch XT1600 excavator-tool carrier was also added last Fall.

One reason Ersland is drilling more frequently is economics. The significant difference in per-foot cost that previously existed between open-cut trenching and horizontal directional drilling (HDD) has begun to evaporate. Initial purchase price and maintenance costs associated with HDD equipment have come down, while restoration costs for open-cut trenching have gone up. In other cases, HDD may be the only option available to navigate the ever-increasing underground congestion of cables, lines and pipes.

Nonetheless, Ersland still finds plenty of applications for both equipment alternatives. For him, as well as many other contractors, trenching isn't going away, and is still a cost-effective approach for many jobs.

Evaluate the cost restoration
Determining whether open-cut trenching or HDD is more cost-effective on a particular job often boils down to your knowledge of the local area and its working conditions, and the affect they might have on machine and crew costs.

"We've been doing this a long time," Ersland says. "But every job is different, so coming up with an exact cost formula is difficult."

For many contractors, determining which method is the most cost-effective begins with evaluating the level of restoration required.

"When I started in this industry 18 years ago, restoration wasn't a big issue," says Richard Levings with the Ditch Witch organization. "You just trenched it, and it was what it was. But that has all changed. The cost per foot to trench is higher than it used to be. You might not get paid much more, but the cost is higher because people are more particular about their lawns and the restoration part of it."

Open-cut trenching is a fast, economical way to place utilities in undeveloped, rural areas. There is no added cost wrapped up in time and tools to identify existing utilities, and there is no chance of cutting through or damaging underground lines, pipes, cables, etc., which can cause additional downtime. Plus, machine setup time and operation are faster compared to HDD. You can also take advantage of a common trench for multiple utilities, further reducing installation costs.

Open-cut trenching may be your only option in states with specific requirements. "Some states require that you lay sand in the bottom of the trench when placing natural gas lines," says Bob Wren, training manager, Astec Underground. "It cushions the pipe to prevent damage. You aren't able to do this process with a drill."

But even in a rural setting, there will likely be some level of restoration required. You may be able to accomplish adequate restoration using the trencher itself. However, some jobs may require bringing in compaction tools, such as vibratory plates or rammers. If you are required to restore the ground to grade for gravity sewers, water drain lines, etc., you may also need to invest in a laser level system.

In addition, you need to factor in the time to restore the trench. "The costs and time constraints associated with restoration can become very expensive, especially when you consider the difficulty in finding laborers," says Levings. "If you go into an existing area with a trencher, you may have to restore it two to three times to get it back to its natural state. It might be less expensive to open-cut that trench initially, but it's more expensive to maintain it."