Project Profile: Infrastructure Repair in One of America’s Fastest-Growing Cities

Sept. 1, 2009

As the 15th-fastest growing city in the United States, Raleigh has seen its population expand by more than 40% since 2000, making it North Carolina’s second largest city.

Located in the state’s central region in the area commonly known as “The Triangle,” Raleigh now supports nearly 400,000 residents in a 115.6-square-mile city incorporated in 1792. As a result, Raleigh offers a contrast in not only styles, but also in maintenance needs, with historic neighborhoods, a major downtown revitalization, and new expansive developments rising rapidly throughout the city.

At the center of the city’s efforts to serve the best interests, safety, and welfare of its citizens is the Raleigh Public Works Department, which consists of 11 distinct divisions including separate Stormwater Utility and Street Maintenance divisions, together composed of nearly 70 trained personnel involved with stormwater infrastructure.

Responsible for the maintenance of nearly 1,000 miles of city and state highways within Raleigh, Chet Lepley, supervisor of Street Maintenance for the past six years, has become the official overseer of the city’s efforts to ensure safe streets through cost-effective maintenance practices. Included in this mission is the identification and repair of problems related to the stormwater pipe system residing under the city’s streets and adjacent to more than 2,000 miles of city-owned curb lines.

“Our job is to ensure the positive flow of our city’s stormwater pipelines,” says Lepley. “We identify the cause of problems as they arise, spot-check potentially troublesome areas, perform some repairs ourselves, and review the repair efforts of outside contractors upon completion.” Large capital projects are sent to the Stormwater Utility Division for design and cost.

“However, this is no easy task, since many of Raleigh’s existing pipelines are designed with corrugated steel, which has a tendency to rust at the bottom within 10 to 20 years of installation,” says Lepley. “Many times, this results in the accumulation of debris that can definitely impede flow rates and create street overflows under extreme rain conditions.”

To combat the ongoing challenges posed by the public stormwater system, as well as to expedite inspection and repair, in 2004, Raleigh initiated a new stormwater utility fee. One of the first benefits of this new funding was the city’s investment in a remotely operated video inspection crawler. The crawler is designed to carry a robotically articulated camera hundreds of feet into pipelines to identify corrosion, deposits, foreign matter, cracks, deformations, offsets, and erosion.

Supplied by Envirosight, a leading manufacturer of video pipeline inspection equipment based in Randolph, NJ, the 12-inch ROVVER crawler selected by the Raleigh Stormwater Utility is fully modular, allowing it to be easily reconfigured with interchangeable wheels, lamps, and cameras to accommodate the inspection of varying line sizes. The compact crawler’s short wheelbase and six-wheel drive enables users to maneuver the device around protruding pipe taps, over thick patches of sludge, up offsets, and around tight turns in piping ranging in diameter from 6 inches to 24 inches.

All of these features were important to the Street Maintenance and Stormwater Utility divisions in Raleigh, because inspections prior to the purchase of the crawler were performed visually by the department’s team of infrastructure professionals. “It was hit or miss,” explains Lepley. “We were constantly guessing on problems and locations. Many times, our crews would dig up three to four sections of pipe to find one bad joint. From day one, the ROVVER increased our productivity and decreased our costs by allowing us to easily and quickly identify all forms of problems, including stress fractures, holes, and intrusions.”

Today, the ROVVER is housed and operated by the Street Maintenance Division. Two-person crews use the crawler’s remote handheld pendant to steer the device through pipe interiors and around multiple elbows and solid obstructions while controlling its focus, lighting, speed, travel direction, and camera orientation. Additional maneuverability is supplied by the system’s automatic motorized cable reel, which senses crawler movement and automatically feeds or retracts cable as needed.

“It is a sophisticated piece of equipment that you don’t have to be sophisticated to use,” says Lepley. “I really had no experience with cameras before now. We received a two-hour, in-field training session from Envirosight, and, in turn, I trained two other employees in its use. Operating the system is easy, and it has greatly reduced our field maintenance time and costs. We are literally completing multiple jobs in one day, when the same amount of identification and repair work would have taken several.”

Raleigh also improved the ability of its Public Works Department to identify and describe its existing public stormwater pipe infrastructure with the purchase of two Envirosight QuickView zoom inspection cameras. Since 2006, the Stormwater Utility Division has used the QuickView cameras as a tool to better describe belowground drainage systems that were previously inaccessible to field crews.

Spot-checking potentially troublesome areas helps avoid problems.
A stormwater utility fee helps the city purchase inspection equipment.

Raleigh’s Stormwater Inventory Program was launched in 1999 to address federal mandates requiring cities to locate and describe drainage systems and identify sources of pollution in waterways. “Our division is working hard to be more proactive,” states Dustin Brice, GIS specialist with the Raleigh Stormwater Utility Division. “We’ve used a two-man QuickView crew to better locate illegal connections to the drainage system. In addition, this equipment helps the city to generate more accurate maps of the stormwater system, as well as check for buried inlets, corrosion, debris, and other infrastructure issues. This information is then shared with all departments–as a resource for infrastructure planning, illegal and hazardous spill containment, and rapidly identifying pipe locations when necessary.

According to Brice, the QuickView is an ideal tool for rapidly observing subsurface infrastructure conditions without the need for confined space entry, as well as capturing detailed color video and digital imagery. Consisting of camera, lamps, positioning pole, and video display, the QuickView is lowered into a manhole and oriented to view pipe sections. Starting with a wide-angle view, the operator slowly increases zoom, enabling the camera to peer deeper into the pipe. In this manner, an operator can inspect entire pipe lengths in minutes, documenting specific anomalies and conditions.

“We’re now able to accomplish in 10 minutes and with one crew what used to take three people at least an hour,” says Brice. “With a straight line of sight, we’re also able to easily observe 100 to 200 feet of pipe in a single session, depending on diameter and endpoint lighting. The QuickView has certainly been a good investment.”

This sentiment is seconded by Lepley, who is hoping to upgrade his department’s ROVVER in the near future with a new selection of wheels and additional imaging equipment. “At a time when municipal budgets are becoming increasingly tighter, the ROVVER and QuickView have combined to greatly speed pipeline repairs and reduce manpower hours,” says Lepley.

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