The pros and cons of green streets
Some cities are said to have streets paved with gold — these cities have “green streets.” City officials in Monona, Iowa, and Shawnee, Kan., were happy to share the pros and cons of having green street projects in their cities.
Monona completed two green street projects and was able to capitalize on funding so the city only paid a fraction of the project’s cost.
Jon Biederman, PE, LSI, branch manager of Fehr-Graham Engineering & Environmental, Monona’s engineering firm, explained in 2013 the city had a State Revolving Fund loan for improvements at the wastewater plant and the Department of Natural Resources was holding out a special prize — adjustable interest rates that would allow funding for a separate water improvement quality project. Biederman said it wasn’t a grant but basically enabled the city to get a free project.
“The timing was such that they fit into that and were the first sponsored project in the state,” he said.
The first project was the parking lot at the aquatic center. Biederman said the center was new, but “the lot was rough — it had steep slopes, crushed stone and no organization to how people parked.”
The aquatic center is right next to a stormwater quality improvement project so it fit within the framework to get the sponsored project funding. Monona put in permeable pavers and used pavers for striping in between spaces instead of painting stripes. “We were able to make a smaller footprint and park more cars,” Biederman said.
With the permeable pavers, any water in the lot or oil, transmission fluid or metals that might fall off a vehicle are all taken below in the ground stone base where it treats the water and releases it very slowly. By greatly reducing runoff, it improves water quality.
Biederman said the pavers require a little more maintenance but not having to paint and repaint stripes every couple of years probably balances it out.
“I think about 90% of this project was covered by the sponsored project,” he said.
This project was completed in the summer of 2014 and the cost was $260,907.02, and the SRF sponsored project paid $245,000 so the city’s portion of the cost was $15,907.02.
The second project was a couple of years later. The city received another SRF loan for a wastewater improvement and was able to improve an adjacent street to the aquatic center, Bulldog Boulevard. The street had been marked for improvement, but the city wasn’t able to do concrete or asphalt, so when able to pull it into the wastewater project, it became more affordable. This project was completed in 2016 and the total cost was $205,526.99. Biederman wasn’t sure the exact amount but thought SRF paid for about $150,000-$175,000 of that cost.
According to Biederman, permeable pavers can be plowed just like any road, but sand can’t be used because it would get into the cracks. Deicer and salt can be used. As for other green infrastructure projects in Monona, he said the only thing that he was aware of was the city had put a stormwater management ordinance in place.
Biederman admitted the permeable pavers cost more, but in some instances, cities may be able to reduce the cost in other ways.
Monona City Administrator Barbara Collins shared the benefits of a green street project, including the visual appeal of the pavers and controlling the dust of a gravel road and parking lot.
“The great stormwater management benefits of the pavers and the financial aspects of running the costs through our SRF loan — getting two projects for the price of one,” Collins said. “There really aren’t any disadvantages. If I had to list something, it would be that there’s some maintenance to the permeable pavers. You have to have a vacuum sweeper to go over it occasionally to suck up any dirt that may clog the small rocks between the pavers.”
Collins added if a city applies for a SRF loan and the sponsor project is still being offered, “I would really look around the town to see where you could do the project.”
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