Durango could spend $6 million over 10 years to address a long-standing problem around town: dirt alleys.
The city has 28 unpaved alleys in its inventory. For years, residents have pushed to upgrade the dirt routes, saying they can’t access their alleys in the winter or stormwater runoff is problematic. More than half of the unpaved alleys could be paved, if the city gets the go-ahead for new storm sewer systems, according to an April Infrastructure Advisory Board presentation.
“We’ve reached out to the EPA (U.S. Environmental Protection Agency) and CDPHE (Colorado Department of Public Health and Environment) for guidance,” said Levi Lloyd, director of city operations. “We’re still waiting to hear back if what we are proposing would be allowed.”
Of the 28 alleys, five can be paved with some design work, reconstruction and possible relocation of underground utilities. Those are located between East Fifth Avenue and East Sixth Avenue, Main Avenue and East Second Avenue, West Third Avenue and Columbine Drive, and Delwood Avenue and Hermosa Avenue.
Four aren’t currently used and don’t need rehabilitation, according to the city. The rest, however, would have to overcome significant barriers before they could be paved.
Some don’t have the grade needed for asphalt to drain without ponding. They would need extensive work, including a redesign, a concrete drain pan in the center, subgrade reconstruction, and utility relocation for sewer, water and natural gas lines.
Two alleys are concave and could cause flooding in nearby basements if paved. Those, plus about 13 others, would need significant storm sewer improvements to be paved.
One way to address those challenges is to install vertical in-ground storm sewer vaults, which requires less space than traditional in-ground storm sewer vaults and works around conflicts with in-ground utilities.
“Traditional storm sewer systems are not going to work,” Lloyd said. “That’s why we’re looking for alternative storm sewer methodology and techniques.”
The vertical systems are experimental and need governmental approval. If Durango receives permission to use the systems, it could pave 16 of the 28 dirt alleys.
Using the vertical systems also depends on the permitting requirements, Lloyd said.
“If we’re in a position we’ll have to pay thousands of dollars in permits every year, we would have to look at other options,” he said.
In the meantime, the city plans to apply new surfacing to eight alleys in 2021. All dirt alleys will also be graded this summer.