Naval Mobile Construction Battalion 74

Story by Petty Officer 1st Class Ryan Wilber

HELMAND PROVINCE, Afghanistan -Without the vital information provided through a topographical survey, it would be impossible to correctly form the foundations for the facilities that will comprise Naval Mobile Construction Battalion 74's new working space or to construct roads. The new Seabee camp at Camp Leatherneck in the Helmand Province of Afghanistan will occupy 21 acres with a main road that's more than 7,000 feet long.

The elevations for the foundations, referred to as pads, the slope of the area for drainage and the shape of the road were all determined by the Operations Department before the survey began. Surveying the expansion site was the first step in the actual building process after the planning phase was completed.

"[The Operations Department] decides what elevation everything will be, the slope or what the pad elevation will be, and then we take it from there. That way the equipment operators know how much to cut or fill," said Spc. Joel Quintanilla, Survey Team member, assigned to the 655th Concrete Team, 19th Engineer Battalion.

In an area full of unknowns, the one thing the engineering aides require to begin their work is what is referred to as a "known point." Fortunately, a group of civilian surveyors working in an adjoining area of the expansion were able to provide a couple of known points.

"It's great that we have the civilians telling us where the known points are. That way we can go off something that they have as [a] reference as opposed to going off [of] nothing," said Quintanilla.

Preparation for the survey begins in the office, setting up electronics. With a minimum of two known points and the camp layout diagram, coordinates are entered into the Trimble S-6 controller.

"We plug the numbers into the S-6 Geodometer and we know where to go from there and put in stakes," said Engineering Aide 2nd Class Adolfo Valdez, NMCB 74 Lead Surveyor.

The process may sound simple, but the fact is that these Seabees were introduced to the Trimble S-6, a rather sophisticated piece of surveying equipment, just two months ago during turnover. Yet, with little training, their own on the job training and a little trial and error, the engineering aides have become proficient in its use. Now they are happy to have the new equipment.

"More advanced equipment makes it a lot easier as opposed to doing it manually where you just have a transit and telescope, using a tape measure rather than a computer," said Quintanilla.

At the expansion site, the survey begins by connecting the base to the controller of the S-6 via Bluetooth. Once connected, the controller is moved to each of the two known points and their elevations entered. This process, called a resection, allows the base to know its elevation and coordinate. Now the surveyors are set to find the elevations of unknown points.

"Once we've entered the coordinates of each point into the controller and [synchronized] it to the base, the controller will lead us to the desired point using line of sight technology. I'll set the pole, level it out and press the button, and the base tells the controller the elevation," said Valdez. "All you have to do is click and measure whatever points you want into the machine, and it will actually take you right where it's supposed to be and it's pretty accurate," added Quintanilla.

Using line of sight technology in the desert where frequent and unannounced sand storms blow through is sometimes challenging, but after a number of long walks across the uneven sand entering elevation points, Valdez and his crew gather the information they need.

Before the survey is complete and the information is ready to be uploaded, the team will have walked nearly every foot of the 21 acre site, not to mention placing 500 stakes to mark off the main road along the way.

Once back in the office, the S-6 is connected to a sophisticated computer program, Terramodel. The Terramodel program provides a visual representation of the site once the coordinates and elevations from the survey points are uploaded.

"The software is made specifically to complement the controller," said Engineering Aide 2nd Class Asdru Arana, Leading Petty Officer. "The Terramodel program shows elevations and depressions, which show us how much dirt we need to bring in or cut to achieve proper drainage for our roads and plot."

With the print out from the program, called a site plan, NMCB 74's Alfa Company, who operates earthmoving equipment, is provided with an accurate representation of the site's topography. They know how much dirt must be removed or added to construct the camp site and road according to the site plan.

Even after the site plan is provided to Alfa Company, the team's work is not complete however. It is vitally necessary for surveyors to be on site to take elevations as the work progresses to ensure the final pad or slope of the road are constructed according to specifications.

"It's a lot of going back out there to make sure they are where they need to be," said Quintanilla.

The importance of surveying, as the first step in the building process is immense. An accurate survey leads to a sure foundation and a new functioning camp for NMCB 74.

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