Call Before You Dig

Understanding the regulations can lead to big savings on infrastructure projects

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The city of Quincy, Mass., has long been plagued by inflow and infiltration. Over half (9.1 mgd) of its 17 mgd average wastewater flow is estimated to result from leaking sewer infrastructure. Addressing the issue was critical, and every dollar had to count.

The city partnered with the regional water and sewer authority and established programs to generate revenue to address the I&I challenges. Not surprising for a coastal city though, the costs for corrective action outflank the ability to fund the repairs. The city established an annual program to fund $1 million to $1.5 million in annual repairs, with a stern focus on stretching every dollar. Part of the path to success is obviously controlling change orders and minimizing costs. One tactic the city used to accomplish this was to put Call Before You Dig regulations to work as a cost mitigation tool for a recent project.

Many older municipalities frown upon the Call Before You Dig requirements due to unreliable or nonexistent records. However, through Quincy’s knowledge of Call Before You Dig, the city reduced project change order claims by 75 percent on the project. With knowledge and understanding of these regulations, Call Before You Dig requirements can significantly help municipalities during underground utility construction.

Quincy’s coastal structure repairs project

Quincy retained the services of Woodard & Curran to help manage, investigate, design and perform construction administration services of their multiyear, multiphase I&I repair program. In the summer of 2012, the city completed the first phase of the Coastal Structure Repairs Project, a challenging effort involving removal and replacement of over 20 tidally influenced brick sewer manholes with watertight precast concrete manholes. This sewer infrastructure is located along the coast and is submerged by the tidal cycle. A salinity testing program found concentrations as high as 70 percent during high tides in these areas and sewer inspections showed that nearly all of the structures had defects.

The Dig Safe process

Call Before You Dig requirements vary from state to state, and in Massachusetts, the program is referred to as Dig Safe.

Massachusetts law requires that the party conducting excavation notify Dig Safe a minimum of 72 business hours p rior to breaking ground. To do this, the specific area to be excavated must be pre-marked to identify construction boundaries. This allows utilities registered with Dig Safe (referred to as a member utility) to mark utilities in the respective areas. Dig Safe itself does not mark out the utilities and simply acts as a notification medium between the excavator and member utilities. Furthermore, Dig Safe does not notify public utilities. The excavator must notify the respective municipality directly (even though the municipality may be the project’s owner).

Member utilities are then required to mark their respective utilities within the 72-hour window prior to construction. Member utility companies mark out the utility within 15 feet in any direction of the pre-marking, which then sets the Tolerance Zone for the respective utility. The Tolerance Zone specifies an 18-inch zone around the utility in which hand-digging must be performed. A standard color is assigned to each utility to distinguish the various pipes/conduits that may be present. Most private utilities are required to join Dig Safe, but it is wise to consult state laws and online resources to identify member and nonmember utilities in your region.

Once completed and after all other local by-laws, ordinances and excavation permits have been satisfied, construction may begin.

Replacing coastal manholes

The manholes to be replaced were located in a busy four-lane road along Quincy Bay with average depths between 12 and 15 feet. Each was leaking groundwater at 7,000 to 14,000 gallons per day.

During construction, the contractor submitted claims due to utilities encountered at nine of these manholes. However, only four claims were approved, resulting in a cost avoidance of nearly 75 percent.

One of the manholes that was replaced had an adjacent 10-inch water main that was hit during construction. A claim was promptly placed against the owner for downtime and additional materials necessary for replacement. The city easily navigated this claim for two main reasons.

The contractor should have been aware of the water pipe because it was shown on the GIS-based contract documents and was marked in the roadway.

Due to the pipe’s proximity to the existing sewer (as shown by the Water Department’s markout and GIS records), state law requires that hand digging be performed within the 18-inch Tolerance Zone. Hand digging did not take place, however and the city cited both of these reasons and this claim was not approved.

Another conflict arose regarding two manholes located where multiple large-diameter sewers converged and utility markouts indicated gas and water piping within the excavation limits. To verify these markings prior to replacing the structures, test pits were conducted that confirmed the tight conditions. These gas and water mains were the primary supply lines for a large portion of the city and all parties were concerned over the potential for interruption.

After several meetings, the contractor negotiated with the city to complete a trenchless cement lining of the two manholes instead. Due to the complexity of excavating in the location, this was viewed as the best resolution. Trenchless cement lining avoided other possible headaches, such as potential water main breaks and difficulty aligning the various converging sewers, and illustrates how complicated utility conflicts may be better resolved with a full understanding of all factors.

Of the claims that were approved, one involved a water service connection that was hit near a manhole structure. The Dig Safe marking for this service was approximately 10 feet away and the contractor could not have been reasonably expected to avoid this unforeseen utility. The century-old water tie card was unclear in this case and the service was not installed in a straight line from the main to the building. Cases such as these are difficult to incorporate into contract documents and the city agreed to process this claim.

More ways to avoid change orders

These examples demonstrate a few of the Dig Safe requirements that may come into play on utility construction projects and that, in most instances, help serve the best interests of the municipalities such as Quincy. Additional measures that Quincy put to use to avoid costly change orders included:

  • Contact private utilities in advance – they often have GIS-based mapping available for a small fee
  • Contractually require emergency materials and equipment on site in the event of damaging a utility
  • Take existing-conditions photo and video report prior to construction and after Dig Safe markouts are painted
  • Work gate valves prior to construction and verify accessibility
  • Conduct test pits every 20 to 25 feet and/or at every marked change in direction for excavations parallel to a utility

“Dig Safe truly played a part in helping Quincy avoid claims and costs,” says Lawrence Prendeville, superintendent of Public Works in Quincy. “This was a highly complex project given the age and coastal location of the sewer lines along a busy road. It’s tough enough to pay for major infrastructure projects without change orders blowing the budget, and knowledge of the Dig Safe regulations played an important part in helping us contain our costs.”

Adam Butler is an engineer at Woodard & Curran and may be contacted at abutler@woodardcurran.com.



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