Dig We Must: Small City Manhole Rehabilitation

In “Considerations for Selecting Manhole Repair Systems,” Dennis Pollack and Mike Oriol take the stance that manhole rehabilitation is an orderly, well-developed, planned maintenance activity. In large cities, such as Atlanta, Chicago, New York or LA, it might be.

A big-city project begins with extensive planning. Engineers select manholes which would benefit the city ifrehabilitated. They select the proper strength for materials for use in the rehab and make the project environmentally friendly. Then the engineers choose a proper technique for rehabilitation, determine the long-term viability of the rehabilitation, and perhaps, conduct apilotproject. One manhole from the group gets rehabilitated. Then, further studies determine if the pilot project succeeded. Only then would full-scale rehabilitation begin.

Tight Budgets for Mid-sized Cities

According to Statisca.com, there are 10 cities in the United States where the population exceeds 1 million persons. Most cities in the U.S. – a total of 35,975 – have a population of less than 10,000. When you look at Cookeville, TN, it’s one of 726 cities with a population of between 25,000 and 49,999 people, and is just below the median population for all incorporated places in the country. If you include the surrounding unincorporated areas that depend on Cookeville for water and sewer services, Cookeville might easily be seen as a representative of most mid-size cities in America.

Its employees face a tight city budget. As far as manhole rehab goes, multiple departments share responsibility for sewer operations. Staff members wear multiple hats in their own department, and sometimes, others. If you ask about manhole rehabilitation, you may find yourself talking to the city engineer, who creates the specifications for all city projects or a clerk who lets you know that manhole rehabilitation’s is a topic the city doesn’t readily discuss. You might speak to a Water Department employee who tells you, in a frustrated tone, that, “that kind of work almost makes staff members cry.” A Sewer Department employee might not know who to refer you to, because so many departments are involved. Although such matters are nominally under their control, other departments, including the Electric Department and Water Quality have a say in the process, as well.

Cookeville, incorporated in 1902, has a city budget that speaks to robust early construction and newer manholes acquired by recent construction and annexation. The basic information is straightforward:

Population (est)	H20 QC Budget - June 2017	Water QC	Repair & Maint. - Lines
32,113	$21,463,861	$1,738,110	$55,000

The city engineer, water, sewer, water quality and electrical departments play a role in manhole maintenance and rehabilitation. However, all say that there's no uniform approach; it begins "somewhere else." Departments and offices mix responsibilities. A city official, who asked to remain unidentified, said, "everything about manhole repair and rehabilitation came from overflows, water damage, broken lines, collapsed streets and resident complaints."

When Manholes Finally Get Repaired

“They’re all plumb full of water,” says Ricky Green of Loftis Underground, atrenchless承包商为肯塔基和田纳西州,“the first thing you have to do is pump them out. Water gets in every way it can, from infiltration/inflow (I/I) to heavy rain or light flash flooding that washes over the cover.” The cover is little more than a means to keep people and vehicles from dropping into the manhole, quipped Green.

Green said he found evidence of brick repointing in the 10 or 12 of the oldest Cookeville manholes he’d been inside. Green said that, “even with light, you had to feel for the mortar joint.” He said the company’s owner had probably been in 10 times that many. “There are a lot of the manholes that are near 100 years old, at least.” Green said that the work he’d done in these manholes wasn’t rehabilitation, unless rehabilitation included conduits for electrical and communications cabling.

As the city expanded, newer areas and subdivisions have brought newer manholes with them. Newer subterranean construction might be part of the reason that this Tennessee city doesn’t experience a substantial need for manhole rehabilitation. A city official, who asked not be identified, said flatly, “Rehab? If one of the older manholes collapsed, it would be a simple matter to yank it out and drop in a new, prefabricated unit.” Green echoed his thought: “It’s easier to dig the manhole out and replace it with a ready-to-use concrete unit.”

Manhole rehabilitation is often the last stage of a minor emergency – an overflow or a street sinking because of broken water or sewer main -- with political implications and consequences. In Cookeville, as in other small cities, the result often ends up in a voter’s yard. That might explain why a clerk at the Sewer Department, when asked about manhole rehabilitation, was confused and said nobody wanted to talk about it. As long as the worst issue they face with manholes is an overflow or some water from a break undermining a street, they don’t discuss manhole rehab.

Maintain Manholes, Don't Rehabilitate Them

Green, however, noticed a difference in the city’s planning for its subterranean world: “In a lot of places, new cabling isn’t being run in manholes.” He said that on one of the city’s main thoroughfares, the access to all communications cables is by handholes. Some of the newer subdivisions have made use of handhole technology – they’re less expensive to install and function as well as a manhole when they’re part of initial subdivision planning. Perhaps the answer to the cost of manhole rehabilitation: follow the small cities’ lead: Don’t rehabilitate them, maintain them or replace them – trenchlessly -- when needed. (Read more in "7 Types of Trenchless Rehabilitation Methods and How They Are Used.")