The pipes, sewers and basements that lie beneath the coastal city of New Haven, Conn., could be flooded by rising groundwater by the end of the century, according to a preliminary study from Yale University and the U.S. Geological Survey.

Much of the city's downtown is less than 30 feet above sea level, and advancing waters in the Atlantic could raise groundwater levels as much as 3 feet near the shoreline, the report said. This has the potential to "inundate underground infrastructure," flooding basements and submerging sewer pipes and utility lines that deliver water and electricity.

Groundwater damage will take a rising toll on property owners, and "utility bills will also rise to re-engineer utilities that were not designed to be installed completely aboveground," said Marcia McNutt, director of the Geological Survey.

If conditions are particularly wet in coming decades, as some regional climate models have predicted, New Haven's groundwater levels could rise even farther. A 12 percent increase in the rate of aquifer recharge from added precipitation, combined with a projected 3-foot rise in sea level by the end of the century, would raise groundwater levels in some parts of the city by an additional foot -- up to 4 feet higher than current levels.

Much of New Haven's groundwater has already risen by as much as 4 feet over the past 100 years, partially because the waters are no longer being used for industrial purposes as they were in the early 1900s.

The specific impact of another 3- to 4-foot rise in groundwater levels is unclear, but many of the city's water mains are already below the water table, according to Tom Chaplik, vice president of water quality and outreach for the South Central Connecticut Regional Water Authority.

Because groundwater near the coast is often salty, it speeds up the corrosion of pipes that it comes in contact with, meaning they need to be replaced more frequently. Chaplik said some of the current water mains date back to the mid-1800s, and replacing them is already an expensive process.

If groundwater levels keep rising, "the water rates would go up because of the costs associated with keeping the system functioning the way it's intended," he said. He added, "Could it be managed? I would say yes."

The report, released yesterday, is the first the New Haven mayor's office has seen on these groundwater issues, said the director of communications, Elizabeth Benton, after reading it briefly.

Yale University, which has more than 300 buildings in New Haven, is planning new construction projects and renovations, and it has voiced concern over how it will deal with the rising waters.

"Rising groundwater levels are expected to be a chronic problem and will likely be a major issue for all large cities along the coast in the future," said David Bjerklie, a Geological Survey hydrologist and lead author of the report.

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC., 202-628-6500