Streets For Tomorrow
A Priority Green Street proposal
By Kali Flynn Burke, Design Studio Intern
10 min read This blog explores how a Priority Green Street policy complements Metro’s Green and Complete Street ordinance. It highlights a project proposal for transforming Davidson Street into a model Green Street, demonstrating how sustainable design can enhance urban infrastructure and improve community resilience.
Educational Poster Example
Urbanization has significantly altered our landscapes, leading to pollution and degradation of nearby water bodies. To mitigate these effects and restore ecological balance, I am proposing the implementation of green streets, soil stabilization along river and creek banks, and floating wetlands for streets adjacent to bodies of water, aiming to reduce pollutant runoff, stabilize soil, enhance aquatic ecosystems, and connect communities with their local waterways.
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Understanding green streets
Definition: Green Streets enhance sustainability and resilience by incorporating features such as bioswales and street trees. These elements improve water and air quality, mitigate urban heat, and support biodiversity. Additionally, these strategies help reduce traffic speeds and provide separation between different modes of transportation. Green Streets utilize vegetation (such as perennials, shrubs, and trees), soil, and engineered systems (like permeable pavements) “to slow down, filter, and clean stormwater runoff from impervious surfaces like streets and sidewalks. They are specifically designed to capture rainwater at its source.” EPA
History and Evolution: In January of 2024, Mayor O’Connell signed Executive Order 45: Green and Complete Streets Policy, reaffirming and expanding Nashville’s commitment to Green and Complete Streets. NDOT has produced a Complete Streets Implementation Guide that serves as a roadmap for navigating existing resources and outlines the process for aligning all projects with this approach.
Core Principles: The Complete Streets approach strives to create a safe transportation system for all users whether that be walking, biking, using transit, or driving through a holistic and proactive design strategy. Complete Streets represent both a process and a product. This approach ensures that when streets are modified, the needs of people of all ages and abilities are considered, regardless of their mode of travel. While not all Complete Streets projects look the same, they are defined by their enhancements to multi-modal mobility and safety.
Green infrastructure is a component that is necessary to achieve Complete Streets. There are six principles that green streets should involve to help mitigate stormwater runoff. These principles include, “(1) protect & restore natural resources (2) promote health, equity, & human habitat (3) design for safety & mobility (4) design for life cycle (5) design for resilience (6) optimize for performance.” - National Association of City Transportation Officials. “Urban Street Stormwater Guide”
In downtown areas or locations that might be good places for public space, we may consider implementing a Green Street parklet. Parklets are small park-like public spaces that usually take the form of parallel parking spaces and can be used to provide seating, dining, or landscape features. The Design Center worked with CSDG in 2017 during PARK(ing) Day to develop a concept for a depave parklet that looked to remove asphalt and create a public space that filtered stormwater run off on 2nd Ave N.
The image above shows a view southeast of downtown view with potential upcoming river-oriented development that will have a substantial impact on stormwater runoff. White boxes indicate Civic Design Center projects and Blue Boxes indicate ongoing developments (Drawing By Remington Lynch, Landscape Planning Associate)
Designating street parallel to the Cumberland River as Priority Green Streets is an exciting idea to act as a "green buffer" and stormwater filter. Integrating Green Street elements—like bioswales, permeable pavements, rain gardens, and enhanced tree canopy—could create a natural filtration layer to treat urban and industrial runoff before it reaches the river. This not only protects the Cumberland's water quality but also enhances flood resilience, supports biodiversity, and improves urban air quality. For industrial zones, including water detention basins or even constructed wetlands along these streets, could be particularly impactful.
As NDOT updates Nashville’s Major and Collector Street Plan, we hope that we can create a special designation for Priority Green Streets for roads that run along our important waterways such as rivers, creeks, and lakes.
Design Center’s Recommendations for Priority Green StreetsThe map above shows streets that were selected based on urban and industrial areas as well as roads that bordered the river and were toward the bottom of neighborhood slopes.
Cumberland River Compact worked with CSDG in 2019 to create a preliminary design that focused on turning Davidson Street on the East Bank into a Green Street.
Designs were created from 6th St to Shelby Park along Davidson and could be implemented with the construction partially shown in the above documents.
Dreaming Big
Master Plan
Plan for connecting Davidson Street green assests
I am proposing the creation of a green street on Visco Dr. in conjunction with the Davidson St. Plan. This comprehensive initiative aims to reduce pollutant runoff, stabilize soil, and enhance aquatic ecosystems, while creating a stronger connection between communities and their local waterways. By integrating bald cypress trees and floating wetlands throughout the area, the plan will create a natural, immersive environment for residents and tourists.
The key feature of this project will be a boardwalk that connects to the greenway at Shelby Park, with additional links to the bike path on Davidson St. This boardwalk will include elevated lookout points, offering views of the cypress trees and floating wetlands, further enhancing the natural beauty of the area.
A bridge designed by a UT Studio a few years ago will be repurposed to connect Davidson St. to Visco Dr., providing easy access to the greenway for people on both sides of the river. Additionally, the Naval Reserve Building has plans to have a kayak launch along with the Hargreaves Riverfront Master Plan. To further increase accessibility and utilization of the river, I propose adding another kayak launch point, creating more opportunities for launching and exiting along the Cumberland River.
Nashville has many underutilized waterways with limited access. By establishing multiple kayak launch points along the Cumberland River, we can begin transforming it into a vibrant and accessible waterway for recreation and transportation.
The Imagine East Bank document includes a proposed road, and I suggest incorporating a bus and bike lane into this road to enhance connections between the two sides of the river. To make the greenway more inclusive and accessible, a bike path with a buffer lane will be created along Visco Dr. This path will connect with the UT Studio Bridge, the Imagine East Bank Road, and Wharf Park, forming a cohesive network for cyclists and pedestrians.
In summary, this multifaceted green street proposal on Visco Dr. and Davidson St. is designed to improve environmental health, promote outdoor activities, and strengthen community ties by creating a more connected and accessible urban landscape.
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What Should Be Included in Green Streets Adjacent to Water Ways?
Signage
Landscape Areas
Transit Orientated / Multimodal
Soil Stabilization Techniques
Rain Gardens
Bioswales
Street Trees
Bike Lanes
Pedestrian Friendly
Permeable Paving
Visco Dr. Planting Plan
Phyto by Kate Kennen and Niall Kirkwood
Phytotechnology Implementation
On Visco Dr., we plan to plant numerous trees, along with shrubs, grasses, and perennials. Various phytoremediation techniques will be employed to help clean the water before it reaches the waterways. Given that Visco Dr. is primarily industrial, these techniques are crucial for preventing contaminated runoff from reaching local water sources.
The bike lane will be constructed from permeable pavement to aid in runoff management, and a buffer zone will be created between the bike lane and the road to ensure pedestrians feel safe. Additionally, near the intersection of Fesslers Ln and Visco Dr., a new kayak launch will be installed, providing access to Browns Creek.
Source: Google
Plant options
Click the + to expand and see recommendations for the different planting types:
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Trees
Common Alder: Alnus glutinosa
Ash: Fraxinus spp.
Loblolly Pine: Pinus taeda
Serviceberry: Amelanchier arborea
Shrubs
Inkberry: Ilex glabra
Red Twig Dogwood: Cornus sericea
Dwarf Fothergilla: Fothergilla gardenia
Vernal Witchhazel: Hamamelis vernalis
Oakleaf Hydrangea: Hydrangea quercifolia
Common Winterberry: Ilex verticillate
Spicebush: Lindera benzoin
Arrowhead Possumhaw: Viburnum dentatum
Perennials
Blue Star: Amsonia tabernaemontana
Columbine: Aquilegia canadensis
New England Aster: Aster novae-angliae
Blue Wild Indigo: Baptisia australis
Purple Coneflower: Echinacea purpurea
Rose Mallow: Hibiscus moscheutos
Blue Flag Iris: Iris versicolor
Dense Blazing Star: Liatris spicata
Cardinal Flower: Lobelia cardinalis
Great Blue Lobelia: Lobelia siphilitica
Beebalm: Monarda didyma
Wild Bergamot: Monarda fistulosa
Meadow Phlox: Phlox maculate
Brown-Eyed Susan: Rudbeckia fulgida
Ironweed: Vernonia gigantea
Grasses
Silver Beardgrass: Bothriochloa laguroides
Fringed Brome: Bromus ciliate
Roundseed Panicgrass: Dichanthelium sphaerocarpon
Eastern Bottlebrush Grass: Elymus hystrix
Little Bluestem: Schizachyrium scoparium
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American Lotus: Nelumbo lutea
Fragrant Waterlily: Nymphaea odorata
Spatterdock: Nuphar advena
Southern Waternymph: Najas quadalupensis
Giant Cut Grass: Zizaniopsis miliacea
Pickerelweed: Pontederia cordata
Water Primrose: Ludqigia sp.
Bushy Beardgrass: Andropogon glomeratus
Broomsedge Bluestem: Andropogon virginicus
Swamp Milkweed: Asclepias incarnata
Spotted Joe Pye Weed: Eutrochium maculatum
Swamp Sunflower: Helianthus angustifolius
Oxeye Sunflower: Heliopsis helianthoides
Scarlet Rosemallow: Hibiscus cocccineus
Path Rush: Juncus tenuis
Longleaf Lobelia: Lobelia elongate
Big Blue Lobelia: Lobelia siphilitica
Beaked Panicgrass: Panicum anceps
Switchgrass: Panicum virgatum
Black-eyed Susan: Rudbeckia hirta
Wrinkeleaf Goldenrod: Solidago rugosa
Swamp Verbena: Verbena nastata
Sweet Flag: Acornus americanus
Fringed Sedge: Carex crinite
Hop Sedge: Carex lupulina
Shallow Sedge: Carex lurida
Broom Sedge: Carex scoparia
Fox Sedge: Carex vulpinoidea
Blueflag Iris: Iris versicolor
Crimsoneyed Rosemallow: Hibiscus moscheutos
Soft Rush: Juncus effusus
Cardinal Flower: Lobelia cardinalis
Arrow Arum: Peltandra virginica
Lizard Tail: Saururus cernuus
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Trees
Bald Cypress: Taxodium distichum
Black Tupelo: Nyssa sylvatica
Sycamore: Platanus occidentalis
Tuliptree: Liriodendron tulipifera
Swamp White Oak: Quercus bicolor
River Birch: Betula nigra
Sugar Hackberry: Celtis laevigata
Sweetbay Magnolia: Magnolia virginiana
Shrubs
Winterberry: Ilex verticulata
Redtwig Dogwood: Cornus sericea
Perennials
Switchgrass: Panicum virgatum
Little Bluestem: Schizachyrium scoparium
Fox Sedge: Carex vulpinoidea
Rush: Juncus effusus
Common Milkweed: Asclepias tuberosa
Tall Coreopsis: Coreopsis tripteris
Prairie Dock: Silphium terebithinaceum
Common Mountain Mint: Pychanthemum virginianum
Wild Blue Indigo: Baptisia australis
Obedient Plant: Physostegia virginiana
Cutleaf Coneflower: Rudbeckia laciniata
Compass Plant: Silphium laciniatum
Sawtooth Sunflower: Helianthus grosseserratus
Swamp Milkweed: Asclepias incarnata
Joe Pye Weed: Eupatorium maculatum
A Plant Scavenger Hunt could be thoughtfully developed for the Green Streets and Floating Wetlands. As people leisurely walk along these biologically diverse areas, they can actively seek out and discover interesting plant life, enhancing their connection to nature. This engaging activity not only promotes awareness of local flora but also helps bring a meaningful placemaking aspect to this important project.
Other Resources:
Plant Scavenger Hunt that could be available to people walking along the floating wetlands
Benefits of Green Streets
Summary of Environmental Interventions
Floating Wetlands
Nutrient Absorption: One acre of floating wetlands can mitigate nutrient pollution from 7 to 15 acres of urban development (Max Rome, Northeastern University).
Phosphorus Reduction: A floating treatment wetland (FTW) covering 10% of a 320 m² pond removed up to 80% of phosphorus, reducing levels from 0.1 mg/L to 0.02 mg/L (Clemson University).
Tree Planting
Runoff Reduction: Planting 100 medium-sized red oaks reduces annual runoff by 112,900 gallons (Midwest region).
Water Treatment Benefits: Reduces 63 lbs. of NO₂ annually, easing water treatment demands.
Permeable Pavement
Runoff Reduction: A 5,000 sq. ft. permeable pavement area reduces runoff by 94.8 gallons annually (80% retention rate).
Water Treatment Savings: Saves $8.71 annually in avoided treatment costs for the same area.
Bioretention Systems
Runoff Reduction: Retaining 80% of stormwater from a 2,000 sq. ft. infiltration area reduces runoff by 113,760 gallons annually.
Water Treatment Savings: Avoids $104.55 in annual treatment costs.
Soil Stabilization (Ottawa River Case Study)
Erosion Control: Stabilized banks with granular materials stopped erosion, blended into the landscape, and created a riparian ecotone.
Biodiversity: Natural vegetation growth mirrored that of undisturbed banks, enhancing ecological integration.
Resource: The Value of Green Infrastructure
Environmental
Green streets increase biodiversity by using native plant species to provide habitats for birds, insects, etc. With the increase in biodiversity it is a good opportunity to raise environmental awareness among residents. By reducing sediment, contaminants, etc. the stormwater quality improves. By retaining runoff in landscapes areas, bioswales or rain gardens it slows the flow from the catchment areas and lowers the risk of soil erosion along with decreasing the stress on the waterways downstream. In areas with rain gardens that have suitable soils, they are able to treat the stormwater and help filter contaminants before it permeates into the groundwater. Water can be directed to irrigate plantings which reduces the need for people to come out and manually water.
Social
Trees and green infrastructure play a big role in significantly reducing urban temperatures. Large trees with adequate soil moisture can cool the areas downs. Tree covered areas encourage outdoor activities like walking and cycling, and green streets make it easier for people to enjoy outdoor spaces without needing to drive to a greenway. Additionally, vegetation improves air quality and reduces greenhouse gases, which is particularly beneficial in industrial areas.
Economic
Complete and green streets can significantly benefit the local economy in several ways. One of the biggest benefits is reduced energy costs due to the street trees shading buildings. Enhanced aesthetics, walkability, and diverse transportation options can increase property values. Recreational activities attract tourists, bringing more visitors to local restaurants and businesses. Green infrastructure reduces environmental liabilities such as flooding and the associated cleanup costs.
Case Studies
Green Streets
Chinatown – Washington, D.C
Xuhui Runway Park – China
P. Street Corridor, Phase 1 – Lincoln, NE
Bagby Street Reconstruction – Houston, TX
US Coast Guard Former Fuel Storage Facility (Guthrie Nichols et al., 2014; Cook et al., 2010)
Wetlands
The Wild Mile – Chicago, IL
Duwamish Floating Wetlands – Seattle, WA
Charles River Floating Wetlands – Cambridge, MA
Green River – Hanwell, UK
Fish Tail Park – China
Permeable Pavement
Rainier Avenue – Issaquah, WA
Pringle Creek – Salem, OR
Stratford Place – Sultan, WA (32,000ft roadway)
Dockside Green – Victoria, B.C
Pacific Avenue – Bremerton, WA (parking lanes)
South Kitsap Industrial Area – Bremerton, WA (shoulders)
Lions and Blueberry Parks - Bremerton, WA (sidewalks and parking areas)
Schley Boulevard - Bremerton, WA
Sylvan Way Meadows - Bremerton, WA
There are many different pathogens found in our waterways. The most common pathogens are Giardia and Cryptosporidium and individuals who come into contact with these can experience headaches, nausea, etc. These pathogens can enter the water through many different ways but one of the most common is from polluted stormwater. Pet waste causes a major issue for Nashville’s waterways, whether that be waste left in the street, your yard at your house, the park, and agricultural farms. If you are asking yourself what you can do, the best thing to do is pick up after your pet.
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Maintenance
A large challenge and consideration is maintenance. From the plants to the functionality of the green infrastructure there will always be maintenance. Some maintenance like making sure the bioswales and rain gardens meet legal standards and function correctly are always going to be there. The other plantings are going to require heavy maintenance for the first couple of years while the plants establish themselves but will require less after.
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Cost
There can be large costs associated with any project like this. Green infrastructure projects may cost more upfront but in the long run, they will help out in other areas whether that be social or environmental benefits, water treatment needs, etc.
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