Underground, unglamorous and largely unseen by the public, a multimillion-dollar public works project is as important to the renaissance under way in downtown Des Moines as the glitzy new buildings that are transforming its skyline.

Any doubt officials had about the condition of underground infrastructure in the oldest section of the city evaporated a month ago when a sewer in the 600 block of Locust Street partially collapsed and again less than a week later after city crews discovered a nearly collapsed sewer at Grand and Second avenues. Des Moines Public Works Director Bill Stowe says similar problems could pop up elsewhere in a city whose sewer infrastructure has outlived its life expectancy.

“We will continue to have failures, and that’s troublesome to us,” Stowe said. However, an aggressive public works project aimed at limiting failures has, for the most part, mitigated the danger to the public, he said. “The prognosis is improving and accelerating, but we still are vulnerable, just like any old river city in the U.S. We’re behind the curve, as I think all major metropolitan cities are.” (See related sidebar.)

Downtown is a top priority in the city’s aggressive public works project to systematically replace its aging, crumbling infrastructure. About $100 million of the 15-year, $500 million project will be dedicated to repairing downtown sewers, some of which were installed in the late 1800s. For example, the sewer line in the vicinity of Grand and Second was built in 1890. Interestingly enough, though, it wasn’t the age of the sewer that caused its near collapse in mid-May, Stowe said. As nearly as crews can determine, the sewer line was nicked during directional boring by a utility company, which has the right to dig on public easements. City crews don’t employ directional boring because of the potential for just that kind of accident, Stowe said.

City Council members emphasized the need for an ambitious public works schedule to address the infrastructure problems. “It’s not at a point of reaching a crisis or being detrimental to the public, but every now and then, there will be a sewer collapse, but by and large, we’re repairing much, much, much more prior to the time they collapse,” said City Councilman Tom Vlassis. Along with Councilman Archie Brooks and City Manager Eric Anderson, Vlassis represents the city on the Des Moines Metropolitan Wastewater Reclamation Authority, a 14-member intergovernmental agency authorized under the Waste Pollution Control Act Amendments of 1972 to clean up the nation’s public waters.

On July 1, the WRA will begin operating under new bylaws that give its members the final say on projects. In the past, the Des Moines City Council had ultimate authority since it owns and operates the wastewater treatment facility. Another significant change allows the WRA to float bond issues. Member governments still have to repay their per capita share of the bonds, but the borrowing doesn’t count against the individual municipalities’ bonding capacity. That’s especially important in Des Moines, whose bonding capacity is often stretched.

Des Moines will repay its share of bonds issued by the WRA with sewer user fees, which may be increased in the coming months. “We want to be careful we don’t get out of sync with the suburbs, but we also have to be realistic,” Stowe said. “Des Moines has unique needs.”

Stowe said the city has lower water user fees than most of its neighbors, which compensates for the higher sewer user fees. Property taxes aren’t tapped for such work, he said.

The city’s sewer improvement project also figures to help cure age-old environmental problems associated with the combination sewers, which provide both storm and sanitary sewer service with the same line. In periods of heavy rains, combination systems can experience extreme backup problems. Combination sewers are being replaced throughout the city and overflows are being closed to enhance water quality in the Des Moines and Raccoon rivers. Des Moines is the only metro-area city with such sewers, and separating the storm and sanitary lines is a arduous task, especially in the densely developed downtown where excavation is difficult, Stowe said.

But without improvements, the environmental problems associated with combination sewers could jeopardize the success of quality-of-life projects, such as the planned Principal Riverwalk, that are part of downtown revitalization efforts. “You don’t want to have combined sewer overflows while you’re walking down the Riverwalk eating a sandwich and thinking of dangling your feet in the river,” Stowe said. “There’s a real desire on the part of the council to improve recreational use of the riverfront in downtown.”

For the most part, the downtown sewer work parallels the construction on Interstate 235, Martin Luther King Jr. Parkway and the Iowa Events Center, but a top priority for the city is sewer work in advance of construction of the Riverwalk. “Any time we have construction projects, it’s the right opportunity to do it,” Stowe said.

Public works crews face special challenges associated with the core city’s proximity to the confluence of the Des Moines and Raccoon rivers. It’s a low-lying area that attracts water, particularly when areas upstream experience torrential rains. Though permitted by both federal and state agencies, the old design of the sewers can result in the release of small amounts of untreated sewage into the rivers.

When the sewers were originally designed, that was “an easy solution,” Stowe said. “Back then, the solution to pollution was dilution.”

The age of the sewers isn’t the only challenge. In addition to old sewers constructed of two layers of bricks held together by mortar that disintegrates over time, there are still a number of wooden box sewers constructed in the 1930s by the New Deal Works Progress Administration program. Within two years, most of the wooden box sewers will be replaced.

Stowe said he is surprised the wooden structures have held up as well as they have. “You would never have thought of building a wooden bridge in the ’30s, but they decided to do that with sewers for some reason,” he said.

U.S. INFRASTRUCTURE IN CRISIS

Crumbling sewer infrastructure is an issue not just in Des Moines, but in most older U.S. cities as well, according to the 2001 “Report Card for America’s Infrastructure” by the American Society of Civil Engineers. Wastewater infrastructure, one of 12 infrastructure categories graded in the report, got a “D,” or near-failing grade.

“The nation’s 16,000 wastewater systems face enormous needs,” according to the report, which cited some sewer systems, like Des Moines’, that are more than 100 years old.

The report noted a $12 billion annual shortfall in funding for infrastructure needs and said federal funding to meet those needs has remained flat for a decade. As a result, the ASCE said, more than one-third of the nation’s surface waters do not meet water-quality standards.

“America’s farmers, fishermen, manufacturers and tourism industries rely on clean water to carry out activities that contribute over $300 billion to our economy each year,” the ASCE report said. “However, the challenge to continue providing clean water remains, as our existing national wastewater infrastructure is aging, deteriorating and in need of repair, replacement and upgrading.”

According to the report, the U.S. Environmental Protection Agency has said that without improvements to the nation’s wastewater treatment infrastructure, the environmental gains achieved since passage of the Clean Water Act of 1972 could be lost.

Grades given in other infrastructure categories were:

Roads and bridges — D+/C

Transit — C-

Aviation — D

Schools — D-

Drinking water — D

Dams — D

Solid waste — C+

Hazardous waste — D+

Navigable waterways — D+

Energy — D+

The bottom line in all categories — D+ — $1.6 trillion in infrastructure needs over five years

A 2003 update by the ASCE shows little progress in any of the areas measured.

GREASE TRAP

It’s not just the age of Des Moines’ downtown sewers that’s putting a crease in city leaders’ brows, but what goes into them as well.

City Councilman Archie Brooks, one of the city’s three representatives on the Des Moines Metropolitan Wastewater Reclamation Authority, said an accumulation of grease is contributing to the instability of the sewers. He believes it may be necessary to enforce regulations requiring restaurants to use and maintain grease traps.

After using automated technology to televise downtown sewers, city crews discovered “a bunch of accumulation of grease from all the restaurants downtown,” Brooks said.

He favors more vigilant inspections, and perhaps requiring restaurant owners and managers to provethat their grease traps have been emptied, cleaned and maintained. The system could work similar to the inspection process for fire extinguishers, which are affixed with tags showing when they were serviced.