Kim Hawkins, a principal with our office, recently spoke at this years StormCon in San Antonio, TX. She and Jim Snyder P.E., who at the time of the design and construction of the street was with Metro Nashville Public Works and who is now with Metro Nashville Water Services , spoke about the process of bring Nashville’s 1st Green Street to fruition. The following is the abstract about the presentation.

ABSTRACT: DEADERICK STREET – TENNESSEE’S 1^ST GREEN STREET

Nashville, TN

Nashville Metro Public Works, Client

Hawkins Partners, Inc worked with the Office of the Mayor and Metro Public Works to transform a historically and civically significant corridor in the downtown area which serves as a physical connector between the city/county courthouse and the state legislative arm of government. Prior to the renovations, the street had become most widely known as the central transfer point for the Metro bus system. In the fall of 2008 the bus system’s hub was relocated one block north to the ambitious Music City Central, presenting an opportunity to re-envision the street itself.

Deaderick Street sits within the Kerrigan Basin, one of Nashville’s Combined Storm Sewer (CSS) basins, that has historically been subject to overflows., it is Nashville’s first implementation of LID features in the public right-of-way, the first green street in Tennessee and one of the first green street applications in the southeast. The renovations to the street primarily focused on addressing stormwater issues and urban trees.  Pervious surface within the right of way was increased by 700% through the use of rain gardens, pervious concrete and .bioswales were implemented in pedestrian bulbs at the intersections.  The site design worked within the context of the existing street and the existing storm drainage system, retrofitting existing storm drains to serve as overflow only. Rain gardens and bioswales were designed with engineered soils to allow infiltration and planted with plants, including many natives, that are adaptable to the extremes of wet and dry conditions. Based on Nashville’s historical rainfall patterns, infiltration rates and variable design factors, it is estimated that over 1.2 million gallons will be removed from the CSO system on an annual basis through this three block urban street..

In addition to the stormwater aspects of Deaderick, a number of other sustainable features were incorporated into the street, including LED lighting, recycled steel site furniture, crushed concrete as base aggregate material, fly ash for concrete and solar powered parking meters.

Hill Center Green Hills, Nashville, TN

A discussion was started on the ASLA LinkedIn group last week regarding street trees’ impact on retail districts. The discussion centered on Professor Kathleen Wolf’’s research. Professor Wolf is a Research Social Scientist in the University of Washington’s College of Forest Resources Department. She has been at the forefront of the research being conducted in this area. Like the landscape architect who started the conversation, I have also been wondering if anyone has taken her research a step further. Professor Wolf’s research relies on user surveys that include both visual preference surveys and traditional questionnaires that ask respondents to rate environments and/or their willingness to pay more for a product.

In an Arborist News article published last year, Dr. Wolf reported on the work she has been doing. In the article, she reports that across all categories, places rated steadily higher with the increased presence of trees. Larger trees rated higher than smaller trees. Her surveys that looked at product pricing within districts with trees indicated that customers are willing to pay 9 percent more in smaller cities and 12 percent more in larger cities.

In her response to an emailed question posted on LinkedIn, she explains that she does not suggest that trees are the panacea for other business challenges and that there is not a simple casual link between having trees and increased revenues. Street trees and streetscapes are positive reinforcement of the “atmospherics” that market researchers consider to have influence on consumer’s buying habits.

I agree that street trees and streetscapes do add a considerable amount to the ambiance and character of place that people enjoy. Anecdotally, I think most people can understand the impact trees have on how we feel in a space/district. However, since retail success can be very sensitive to location and surrounding demographics, it can be difficult to make a clear connection between retail sales and trees. I hope that research continues to make the case, and like the sophisticated interior research done by market researchers, we can continue to increase our understanding of this relationship.

The article in Arborist News also offered some guidelines on street trees in retail districts such as the proper tree species, size, maintenance, and providing signage that contrasts with the trees’ foliage. I would add that tree placement along the street and their relationships to the doors, windows, and dividing walls between businesses are also important to consider.

The reports on Professor Wolf’s website Human Dimensions of Urban Forestry and Urban Greening are worth checking out.

-Brian Phelps

The recent transformation of Deaderick Street recalls the historic importance of the street and enhance the corridor’s prominence as an important civic axis. Prior to the renovations, the street had become most widely known as the central transfer point for the Metro bus system. In the Fall of 2008 the bus system’s hub was relocated one block over to the ambitious Music City Central, presenting an opportunity to re-envision the street itself

The renovations to the street primarily focused on addressing stormwater issues and urban trees. The existing streetscape was home to an assortment of unhealthy trees ranging in sizes from 2” caliper up to 24”+. Each and every one of them were shoehorned into a 4’x4’ planting zone and struggling to adapt to urban conditions. The renovations included removing those trees and providing larger and deeper planting areas that would not only give a larger volume of soil for the tree roots, but also provide many areas in which the stormwater could travel to, thus reducing the loads into the storm system. Bioretention zones were implemented in pedestrian bulbs at the intersections and in relation to the existing catch basins. These planting areas were also excavated to a depth that would accept enough engineered soils to allow infiltration and planted with plants that can adapt to the extremes of wet and dry conditions. Pervious area within the corridor was increased by over 700%.

Many other elements of sustainability were included, such as:

• Crushed and recycled concrete used for the pavement subbase,
• Fly ash utilized in the concrete mix,
• Porous concrete,
• LED light fixtures,
• Native and drought tolerant plant materials,
• Solar powered parking meters,
• Water efficient irrigation system,
• Many local vendors and fabricators,
• The addition of bike racks to help encourage a healthier way to travel, and
• The addition of recycling receptacles along the street.

We’re hoping that in the near future, permanent retail kiosks that were proposed in the master plan will be added to the street, further enlivening the corridor. Those kiosks are proposed to have an extensive greenroof on each. In addition, the master plan identified areas for future free standing retail buildings and liner buildings that could be added on the blank facades.

- Laura Schroeder

Jim Snyder, Metro Public Works and Kim Hawkins, Hawkins Partners
present graphic panel to Mayor Karl Dean.

View of Streetscape During Event

View from Public Square to Legislative Plaza

On October 8th, Nashville’s first green street opened with great fanfare. Mayor Karl Dean, Kathleen O’Brien (President and CEO of the Tennessee Peforming Arts Center), and Billy Lynch, the Director of Nashville Public Works Department, spoke at the street’s eastern terminus in Public Square. The celebration also included music by Decca Records and SONY/ATV artists One Flew South, featuring Grammy Award-winning composer Marcus Hummon, and Transit, a band formed by Nashville MTA employees. A recording of the event has been posted on Metro Nashville’s website. (Link)