Shawnee has just begun its green streets projects with a couple of trial projects starting construction soon, aimed at spurring development on its west side. Assistant City Manager Caitlin Gard, senior development engineer Raegan Long and community development Director Doug Allmon are spearheading this project and said city officials and planning boards have praised their plans.
Gard said over the course of the past year, the city started working on a strategic plan, something it hasn’t had until now. Shawnee is a large geographic area of about 42 square miles with a population of about 68,000; it’s not very dense, but it has board demographics — physically and in terms of age and income. Some of the city would also be considered rural.
As thoughts focused on Shawnee’s future, Long and Allmon were brought into the planning process. A couple of the things they looked at included how to promote development and get infrastructure installed; how to get a comprehensive plan for a land use guide in sync with how they wanted the city to be; and then they considered whether or not all the streets needed to be the same.
Long said everyone considered what they wanted the street to feel like when drove on. Finding cost savings was another discussed topic.
“Not having much of a tax base (in that part of town) makes it difficult,” she said.
There were a lot of flood plain issues and a lot of rocky material in western Shawnee, making it difficult for large developments. When looking at ways to save, not installing curbs and gutters or a traditional enclosed storm sewer system would cut costs. Instead, more of a ditch system approach was examined, where water would flow through a creek system and out to the Kansas River. Most of western Shawnee has residential enclaves where the streets were never properly engineered and site distancing is difficult, according to Long.
She said a big priority for the green streets project was “incorporating our trail system into the green streets providing connectivity to parks, subdivisions, even schools.”
“We’re known for our trail systems and our outstanding park department. Every one-third of a mile has green space, parks or trails, and we want more connectivity to the trails,” she said.
Shawnee also plans to reduce the lane width; instead of the traditional three-lane road with a center turn lane, it would reduce the lane width on these green streets. Narrower streets reduce pavement, which saves on costs, labor and maintenance as the city is plowing one-third less. Green streets also provide better water quality by decreasing runoff.
“The big picture for us was recreational use and sustainability. We’re hoping to encourage economic development in a most cost-efficient way,” Long said.
Gard said the cost estimate for construction of 1 mile of road was $5.48 million versus the cost of a mile of green street at $3.38 million. That’s a savings of $2,104,080 in construction due to eliminating curbs and gutters, one lane and enclosed storm sewer. Over a 10-year period, a cost savings of $19,490 per mile in milling, overlay and plowing has been estimated.
Long said Shawnee is incorporating the green street projects into the comprehensive plan for 2021, but it has a couple of trial projects to be completed this year, and the first is starting construction next month.
Allmon said, “Part of the profile that’s different from a typical ditch-style road is that we’re including trails and connector streets adjacent to the ditch using sidewalks and multimodal as part of the street section.” This should make them more useable for residents.
According to Allmon, many of these streets were annexed into the city from the county, and as they were developed, it happened “almost piecemeal with no connectivity. In many cases, the horizontal and vertical alignments were not safe for some of the travel capacity we’ll be experiencing.”
He said in the past when development started, Shawnee required that streets be developed to the highest standard, but that meant sometimes only one side of the road was improved or that there was no connectivity to the collector or arterial road. Ultimately, planners decided to have a more strategic plan and make sure the road is developed to the best extent and that improvements are made on both sides of the road.
As fas as benefits, Long stated, “Hopefully, (there will be) more economic development. If we enhance the businesses and restaurants in the western portion of Shawnee, people will stay local.”
Stormwater treatment and quality is also a benefit as the temperatures are kept down since it’s not going through an enclosed system and, instead, flows more naturally through the ditches. More improved streets mean better walkability and quicker response times from police and fire. A long-term benefit is the discovery that there’s no need to overbuild roads if not necessary, creating extended cost savings.
“We’re not building ultimate roads and having them go nowhere,” Allmon said.
As for disadvantages, Allmon noted, “This is an interim solution. If density increases or changes, they may end up having to widen the street someday.”
It is possible that in 50 years Shawnee may have to go back and widen the road, which might be costly; however, Allmon said because of the city’s study, this is not expected to occur. Still, some measures are being taken just in case. Shawnee is acquiring the ultimate right of way now, and any trees or utilities will be placed outside of a possible widening of the road.
Long said another potential disadvantage is the mowing of the ditches and how it’ll look, but every subdivision has a homeowners association, and the HOA will be responsible for mowing and maintaining the ditches.
“The city may have to go in and re-ditch at some point,” she said, but that’s not unusual.
Gard said there’s also an educational piece to this project. “For so long we’ve said curbs and gutters were better.”
So if residents are questioning their omission in these new green streets, they can be shown the amenities that are a part of the design, including streetlights and walkability.
Allmon said part of that educational piece is letting people know with green streets there’s not as much disruption. “With this we have the flexibility to plan around obstacles, we can engineer around them so it’s not as significant an impact as a true curb-and-gutter street.”
Long added the green street project can use recycled asphalt or crushed aggregate as a base and the streetlights will be LED.
“This is great safety improvement as well,” Allmon stated. “Those inherited county roads are real narrow and unlit, so from a safety standard, this is big.”
Finally, Long noted, “We’re striving to make it as green as possible. Each green street is unique.”
When it comes to initiating green infrastructure in your city or town, it may mean looking around your city with green-colored glasses.