How did they do that? Water main installation using directional drilling

With all the construction activity around town in recent weeks, we at the "New Rockford Transcript" are enamored with all the machines, people and processes. So, Publisher Amy Wobbema went on scene to capture all the phases of the water main replacement project to help readers understand what's actually going on. In this week's edition, we're highlighting the directional drilling process used downtown and in select other areas, where the existing water main remains in place while a new one is pulled through a hole made underground. In future issues, we'll document the excavation process- where crews physically unearth the old cast iron lines and replace them with new ones, the street rehabilitation process, and even profile some of the workers on the crew.

Download the photo story in our print edition here: https://www.newrockfordtranscript.com/home/cms_data/dfault/pdfs/misc/2020-05-04.pdf

Phase 1: Utility location

Crews locate all the water service lines to residences and businesses as well as other utility service lines such as fiber optics and sewer. In order to locate these lines, small holes are dug using a vac truck.

Phase 2: Directional drilling (boring)

A horizontal directional drilling machine is used to create a hole for the new water main to follow at 8 ft. depth. This machine uses a metal rod and a special bentonite clay slurry similar to concrete to bore a hole through which the water main can be pulled. The boring is done at least three times, first to dig the hole, second to ream the hole, and third to pull the pipe. A 12-inch diameter reamer and bore head are used to create the hole.

Phase 3: Pipe Installation

The new PVC water main is pulled through the bore hole 16 feet at a time. In the photo at right, a backhoe bucket guides the new water main through the bore hole. Go to our Facebook page to see a short video of the pipe installation phase.

Phase 4: Testing

Testing is done to ensure the water main does not have any leaks, and that the water is safe to drink per the ND Department of Environmental Quality standards. The photo at right shows a pressure gauge used to determine if there is sufficient water pressure in the line. Low pressure indicates a leak somewhere in the new main, which must be addressed.

Phase 5: Service line connection & operationWorkers use an excavator to dig down to the new main near the corporation stop, or valve that controls the flow of water to a business or residential service line. Once the valve is closed, they disconnect the service line from the old main and attach it to the new main. Then the hole is backfilled with dirt and leveled off. Businesses along Seventh Street, including Miller's Fresh Foods, were getting their service lines connected this past week.

Progress Update

As of Thursday, directional drilling was underway along Eighth Street from First Avenue North to Second Avenue North.

BEK also installed new water mains on Central Avenue and First Avenue North from the west frontage road to Second Street last week. Once Carstensen Contracting completes its drilling along Eighth Street, their crew will connect the two blocks of pipe by installing new main along Second Street from Central to First Avenue North using the directional drilling process.

BEK Consulting plans to begin digging in new lines under Central Avenue downtown, from Eighth Street to 10th Street, soon.

For up to date information on where crews are working and what you might encounter on those streets, please go online to http://www.interstateeng.com/newrockford/. The interactive map highlights the progress throughout the city and alerts residents and travelers as to where activity is imminent or already underway.

Note: A shout out to Jeff Douty of Interstate Engineering for showing me around the work sites and taking photos in my absence, and for Wade Senger of Interstate Engineering for his help with the technical terms. Also, a special thank you to the workers who have been so "photogenic!"