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City faces challenge with aging storm pipes

Consultant says it will cost millions to upgrade system
Tuesday, February 17, 2009 | 5:45 p.m. CST; updated 5:47 p.m. CST, Wednesday, February 18, 2009
A storm drain at the corner of East Walnut and Ann Street shows corrosion, a condition caused by excess water, salt from winter streets and surrounding soil content. This drain is one of several being assessed by Columbia's Public Works Department, which routinely monitors the drains for signs of wear and tear.

This story has been modified to more accurately describe the age of pipes in the city's storm-water system.

COLUMBIA — The potholes on Middlebush Drive near Fairview Road are not only inconveniences, but they also are warning signs that all is not well beneath the surface. Potholes on Brandon Road tell the same story. Under these roads sit deteriorating storm-water pipes that have outlasted their lifespan. Potholes are the first sign of failure.

When storm pipes fail, the damage can be severe. Flooding occurs, and roads can collapse. When the bottom rusted out of a pipe near the former Biscayne Mall Walmart a few years ago, the water flow twisted the metal, washed out the pipe and created a sinkhole about 12 feet deep and 30 feet wide in the store’s parking lot.

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Most of Columbia’s storm pipes are more than 50 years old, and some are more than 100. With no regular inspection program, the Public Works Department is battling time and limited money to fix the ailing infrastructure before more collapses become inevitable. A consultant for the city has recommended an aggressive inspection, repair, replacement and maintenance program that could cost as much $100 million over the next 20-plus years and require significant increases in monthly storm-water utility bills.

Elise Ibendahl, of the consulting firm CH2M Hill, said most storm pipes downtown were installed in the 1800s. But because the city has yet to experience major problems, replacing them has fallen low on the priority list for citywide repairs.

“When it’s under the ground, it’s easy to forget,” Ibendahl said. “Out of sight, out of mind.”

Pipe history

Tom Wellman, an engineering specialist for the Public Works Department’s storm-water utility, said there is no way to figure out the exact age of the city’s pipes. The department uses maintenance records, street and subdivision construction dates and aerial photos to make the best guesses it can. Because most of the pipes were installed as the city was being built, determining the age of the subdivision or the street under which the pipe is located is the best way to estimate.

Wellman acknowledged the need for maintenance and repair, but he said the pipes have held up well.

“The fact that they are still supporting the system means they are still in pretty good shape,” Wellman said.

Despite their age, Ibendahl said much of the several miles of pipes that date back to the 1800s are more stable than the eight miles of corrugated metal pipe Columbia installed in the 1960s and ‘70s. Pipes from the 1800s are called rock boxes because they are made of large rock built into the shape of a box. The city also installed concrete boxes in the early 1900s. Both the older types of pipes are in better shape than their corrugated metal counterparts.

The corrugated metal pipes installed in the ‘60s and ‘70s have a life span of 33 to 44 years, compared to newer corrugated metal pipes that have a lifespan of 50 to 70 years. These pipes are spread all over the city but often are found in subdivisions built between 1960 and 1970. A desktop corrosion analysis of Columbia’s corrugated metal pipes confirmed they are deteriorating.

“It’s a lot cheaper to put in corrugated pipe than to put in reinforced concrete pipe, but there can be a price to pay,” Ibendahl said. “Anything installed before 1980 needs to be inspected because there’s a risk of failing, and pretty soon.”

Changes will cost big money

In a 2008 report from Ibendahl, CH2M Hill recommended the city develop a program for inspecting, repairing and replacing its storm-water pipes within the next year or two. The report recommended the city replace within 10 years at least 75 percent of the corrugated metal pipe that has exceeded its life expectancy, then replace the remainder of that within the next 25 years. CH2M Hill estimated the cost at $5.8 million per year through 2019 and another $2.7 million per year from 2020 to 2033. That’s a whopping total of more than $100 million.

To help cover the cost of improving the storm-water system, CH2M Hill is recommending significant increases in monthly bills for storm-water management, which haven’t been raised since the utility was established in 1993.

Storm-water bills now range from a low of 65 cents per month for apartments and small houses to a high of $40 per month for commercial developments of more than 100,000 square feet. CH2M Hill recommended in its summer report that the city increase those rates by 105 percent this year and by 156 percent in fiscal 2010. That would boost the range in rates from a low of $2.08 per month to a high of $65.52.

After that, it suggested, the city should review its rate structure every five years.

Wellman said the actual costs might not be that high. He said once the city establishes an inspection program, it should show that not all the pipes need to be replaced.

“I expect most of them to be in decent shape,” Wellman said.

City Manager Bill Watkins agreed.

“Before we start talking about price, we need to get a real good handle on what the need is,” Watkins said. “I want to wait on spending all these millions of dollars on something there isn’t a need for.”

Watkins said the city is putting off discussion of the storm-water system’s needs – and how to pay for them – until fall.

Funding hasn’t always been so tight. Before 2002, the Public Works Department won state grants of between $160,000 and $245,000 per year to upgrade its storm-water system. Since the grants fizzled out a few years ago, the storm-water utility has paid the price. Much of its equipment is outdated, and there isn’t enough staff to adequately inspect and maintain the system.

“The budget is shot,” Wellman said. “We feel like we’re broke.”

Funding is so limited, in fact, that the Public Works Department had to lay off the only person who was inspecting surface pipes, and that was a part-time employee. Most city pipes haven’t been inspected in recent memory.

“It’s definitely not enough,” Steve Hunt, a civil engineer in the Public Works Department, said of the former one-person inspection unit.

Even when the city has an inspector, learning where problems exist in storm-water pipes can be difficult. The best way to get a look at the inside of pipes is placing a closed-circuit television camera inside them. It’s a tough chore, and some pipes can’t be inspected with a camera because they have no entry points.

Help on the way?

The city may get some help from Amendment 4, a change in the state constitution that voters approved on Nov. 4. The amendment eased restrictions on state assistance to storm-water utilities by eliminating a previous requirement that funds be offered as 50 percent grant and 50 percent loan. That means the state has more flexibility to send the money where it’s most needed. The amendment also eliminated the previous cap of $20 million per fiscal year on appropriations to the state’s storm-water control fund.

 

Wellman agreed with the recommendation from CH2M Hill that pipes installed before 1970 be inspected and either replaced or repaired as soon as possible. Some limited plans already are in the works. The city this fall will have contractors line the insides of a few hundred feet of badly deteriorating pipe. That project will focus on areas where pipe failure could cause particularly bad damage and where removing and replacing old pipe would be disruptive.

Despite the uphill climb, public safety remains a priority for the Public Works Department, Wellman said.

“Our goal is to have a program where we are keeping track of the pipe system we have and regularly inspecting them,” Wellman said. “The goal is to keep the public safe from flooding and infrastructure failures.”

 


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Comments

Lori February 17, 2009 | 10:27 p.m.

Can someone please tell me why some of the much anticipated stimulus money that the City of Columbia hopes to receive is not going to pay for a project such as this? Instead, a large portion of it is targeted to go towards useless projects such as the city airport that is failing for a reason. It will also be spent on new stoplights around town. Why can't the money go for something that is really necessary?

(Report Comment)
Ayn Rand February 18, 2009 | 6:34 a.m.

Because it's more politically correct to spend the money on even more upgrades to Douglass Park.

(Report Comment)
Charles Dudley Jr February 18, 2009 | 11:17 a.m.

Ya because the citizens of Columbia voted that way a few years ago with out realizing the evil they allowed to get away from them. Now look what we have.

(Report Comment)
John Schultz February 18, 2009 | 1:14 p.m.

The dangers of democracy (not that we live in one like most people think).

(Report Comment)

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