Fixing the Straight & Narrow

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Carolina Environmental Contracting (CEC) has made a name for itself in the northcentral part of the Tar Heel State by successfully blending the old with the new. On a regular basis, the Mt. Airy, N.C.-based environmental contractor makes great strides in offsetting the scars of development by restoring natural beauty to many of the region’s streams, creeks and other waterways. While that was once a time-consuming, stake-intensive effort, the company today uses GNSS technology to improve both the speed and efficiency of that effort. CEC’s stream restoration jobs are now virtually stakeless, accuracies are impressive, and the end product is once again a sight to behold.

Good Idea Gone Bad
To see a naturally flowing, meandering stream is to see both the beauty of nature on display and some very basic principles of physics at work. Streams meander or take a snakelike path through an area when the water, as it follows its natural downward trajectory, erodes the outer banks, depositing silt on the inner part of the stream where less energy is present. Over time, the result can be a picturesque winding stream that, while beautiful to behold, can present serious challenges for farmers and landowners as the stream encroaches on farm land or structures. In the past, to resolve that concern, streams and channels were simply straightened in order to maximize the amount of farmable land.

If, for example, a stream ran through a farmer’s field, government funds were made readily available to re-route that waterway to one edge of the property, essentially replacing a winding stream with a straight ditch. This was a particularly widespread practice in the first decades of the 20th century. While straightening a waterway is certainly effective at maximizing the available land, it did nothing to lessen erosion–in fact, it actually worsened it. The by-product of this program was a huge number of ditches nationwide which lacked both the beauty and natural effectiveness of the original stream.

Fast forward to the early 1970s and The Clean Water Act of 1972 which had, as one of its main statutes, the resolution of wetlands adversely affected by development, and the offset projects that are driven by such encroachment. Essentially it dictated that, if a government agency or private developer’s project impacted wetlands or a waterway as a part of its project, an equal number of linear feet or acres of existing "damaged" waterway in that watershed or one adjoining must be mitigated. As a result of that Act, today, companies like CEC, in concert with engineers, designers and surveying professionals, work hard to bring area streams back to their original pristine state. By so doing, they not only meet a critical mandate to allow development to proceed elsewhere, they also improve the overall quality and viability of that stream for generations to come.

CEC-ing a Need
Founded in 1991 by Joanne Cheatham, Carolina Environmental Contracting, Inc. excels in a range of environmental-focused projects including stream mitigation, the construction of wetlands and greenway trails, the installation of storm water management systems, and more. According to Wayne Taylor, CEC’s specialty division manager, while the company’s commitment to environmental work has not changed in their nearly quarter-century in business, the manner in which they do so most definitely has.

"A recent stream remediation project in the Marion, N.C. area is a great case in point," he said. "That project, remediation of the Neighbor Branch/Walton Crawley Branch, includes restoration of 2,500 linear feet of stream and the construction of more than 90 stream structures. The stream had not only been straightened over the years, it had also begun to flow into a pond. From an environmental perspective, that is rarely good, since a pond will allow sediment to settle rather than move along. So, based on a plan from ICA Engineering in Raleigh, we had to take the pond out, move the stream back in the location where it originally ran and then reconstruct the pond alongside it."

Work on the project–which included additional remediation of 1,000 lineal feet at nearby Bob’s Creek Reach–started in February of 2015 and had a five-month timeline attached to it. While that could have presented a problem in the past, CEC’s use of GNSS based machine control from Topcon Positioning Systems on its dozer and excavators made it easily do-able. CEC has been a staunch user of GNSS solutions for more than seven years now, a move made easier thank to the support of their dealer Benchmark Supply and Mike Gaillard in the Concord, N.C. branch.

"One of our former project managers had heard about the strengths and advantages of this technology and talked us into it. Today, in addition to several Topcon base/rover/ data collectors, we have Topcon machine control on three excavators and a dozer. It was definitely the right move for us to make."

Familiarity Breeds Success
To get to the point where they could begin work, CEC needed a digital model to provide guidance to the machines running Topcon 3D-MC2 and 3D-MC systems. Raleigh-based Turner Land Surveying, PLLC, one of the area’s most in-demand survey services, answered the call, providing both initial control and the necessary models.

"A project like this was ideal for GNSS, but it was still a complex job" said David Turner, a managing partner in the firm. "However, my wife `Lissa’–also a PLS and head of the company–and I, both have previous experience working with design engineers and, as a result, are probably better suited than most other firms to giving contractors like CEC the total product they need. The pattern of the streams±the meandering characteristic being brought back in–would have made staking extremely difficult. In such a case, we would stake the beginning, the mid-point and the end of each curve, set out the radius points, establish offsets to the structures, and so on, and then manually pull tapes and use a differential level to determine elevations. Doing so for each of the curves in that design would have been brutal."

Critical Files
By comparison, he said, GPS, when it can be used, is much more cost-effective in terms of both speed and manpower. "It can take a full field crew ten hours to stake out a segment of a stream project like this. By comparison, I can create the model which makes staking unnecessary, by myself in my office in half that time."

When Turner’s work was complete, he presented CEC with a series of files including a line file (.LN3) that included all the line work contained in the ICA engineer’s drawing. More than just the top and bottom of banks and a centerline, it also indicated the outlines of the structures, the easement line, areas that would get silt fence, etc. "At this point," he said, "we can also determine what type of machinery this will be output for. Since most of my North Carolina customers use Benchmark Supply, the bulk of that work is done with Topcon equipment in mind."

Additional files included a roadway alignment file (.RD3) to indicate the centerline and tell the operator where they are at–with regard to the design–when they place their bucket or blade anywhere on the stream or site. The package was wrapped up with a .TN3 file, essentially a converted version of the DTM surface, which allows the operator to not only see their bucket’s elevation, but also tells him how much to cut or fill to get to the design elevation.

"For CEC’s newer machine control systems, we also gave them a .TP3 file which is a compilation file generated by Topcon 3D Office software," said Turner. "It takes those three individual files mentioned above and combines them so CEC only has to load one file when they get into the machine."

Bring Back the Beauty
At the Neighbor/Walton Crawley Branch site, many of the areas were extremely wet prior to work being done. To alleviate that, a Godwin DRI Prime pump with a 6-inch line was used to dewater the area, diverting water downstream past the active work site and allowing it to dry out. CEC then used a mix of equipment to begin the restoration effort.

"We used a John Deere 700 dozer with Topcon 3D-MC2 to create all the outside slopes, the adjacent flood plains, and so on," he said. "But the structures themselves– whether they were rocks, logs or a combination of the two–were done using Volvo EC 220 and EC290 excavators. A number of the structures were log vanes which involved placing entire logs across the stream, both to reduce the velocity of the water and to help step down the elevation of the stream. The Topcon system was so accurate that our operators would regularly place the teeth of the bucket on a log to confirm that they were on grade."

That degree of confidence is hard won. According to Taylor, many engineers, when they first work with CEC, get onsite and become concerned when they don’t see any stakes. "That’s understandable," he said. "Old habits die hard. But once we show them the accuracies we are getting, they are fine. There’s no denying that, with machine control, we’re faster and can run leaner. Without it, an operator working on a structure would need someone to help lay it out, someone to shoot grades, etc. Using GPS, one man can completely build these structures by himself–and the end product is always right on the money."

Long-Term Benefits
Additional work on the project included firming up the stream’s embankments, occasionally through armoring with rip-rap but more often through the use of Coir Mats and the planting of live stakes. This approach takes dormant, live, de-branched, woody cuttings of a species–silky willow, silky dogwood, elderberry, and nine bark were among those used by CEC–and driving them into the ground. When the plants mature, this technique creates a root mat that stabilizes the soil by reinforcing and binding soil particles together. More than 2,400 live stakes were planted at the Walton Crawley project.

When this particular restoration project wraps up, CEC will have a sense of pride that their efforts have helped improve the overall quality of the watershed and the stream at Walton Crawley. They will also be confident in the fact that, using machine control, they did the job in the most efficient and cost-effective manner possible.

"There’s no doubt in our mind that this technology pays for itself pretty quick," said Taylor. "We’ve had jobs on which we eliminated more than $20,000 in survey costs alone. Plus we can do the job with at least one fewer position, so there is substantial savings there as well. When looking into new technology like our Topcon systems, we are fortunate to have an owner like Joanne who will ask: `Do you need it?’ and if the answer is yes, she’ll immediately say: `Go get it.’ That’s really allowed us to grow and become the company we are today."

Larry Trojak is a communications writer for his own firm, Trojak Communications, in the town of Ham Lake, Minnesota. He is a frequent contributor to The American Surveyor.

A 5.443Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE