HomeMy WebLinkAboutOPE Archive - 09/28/2015 - 22.3 - Serenbe 2.1.14Serenbe:
Hamlets Nestled in a Greenway
Location: Chattahoochie Hills, GA
Developer: Steve Nygren, Atlanta, GA
Site Designer: Phillip Tabb, College Station, TX
Dates: 2004- ongoing
Serenbe is a 1,000-acre community located 30 miles southwest of Atlanta in the rural City of
Chattahoochee Hills, a relatively new municipality (incorporated in 2007) covering 33,000 acres,
about the size of Napa Valley. With roughly 2,400 people, the city’s density is about one person
per 14 acres, although the vast majority of land is zoned for one-acre lots. Both Serenbe and the
City of Chattahoochee Hills are located in what is known as the Chattahoochee Hill Country
(CHC). The CHC extends over 65,000 acres (about 100 square miles) of rolling hills, streams,
farms, and forests in southwestern Fulton County and parts of Douglas, Carroll and Coweta
Counties. This is one of the last remaining rural areas within 30 minutes of Hartsfield-Jackson
International Airport, the world’s busiest airport.
Combining greenway planning and hamlet design, 70 percent of Serenbe is permanently
preserved. This contrasts starkly with conventional subdivisions which conserve none of their
land, and typical rural clusters in Georgia that preserve only 30-40 percent. A central aspect of
the greenway open space system is a 25-acre organic farm supplying produce to a weekly
farmers’ market and onsite and regional restaurants, which also creates an identity for this new
community of four hamlets, projected to accommodate up to 1,200 homes and 250,000 sq. ft. of
commercial space (Kimble, 2010)
.
Figure 22-3.1: The main street in Selborne, the first hamlet to be completed, combines contemporary and historic building
styles. Serenbe’s overall plan, designed by Phillip Tabb, consists of three omega-shaped hamlets designed to follow the terrain,
gracefully oriented around a variety of lower-lying natural areas. (The fourth hamlet has not yet been designed.) Sources: Photo
by Serenbe Development Corp. Map by Phillip Tabb
The history and context of this project are remarkable. Responding to official projections that
estimated construction of 40,000 new homes during the next several decades, a group of
concerned citizens led by Serenbe founders Steve and Marie Nygren founded the Chattahoochee
Hill Country Alliance in 2000 to figure out how to balance growth and preservation objectives.
Nygren notes that the first edition of this book (Rural by Design) was very helpful to him in
communicating planning ideas to the public during this period. (email from Steve Nygren,
1.17.12)
In 2001, The Alliance received a grant (from the Fulton County Economic Development Board)
and engaged a team of professionals to facilitate a planning process, document a vision, and
create a new region-wide land-use plan merging sustainable development with land conservation.
During the following year the resulting Chattahoochee Hill Country Community Plan was
incorporated the South Fulton County Comprehensive Plan and the Chattahoochee Hill Country
Overlay District Ordinance was adopted by the county. Recognizing that land purchases, even
when supplemented with conservation easements, would move the needle only slightly, creative
development strategies were adopted, including TDRs and mixed-use village design. TDRs in
some form (perhaps development transfer charges or DTCs, as described in Chapter 18) will be
essential to achieve the desired density levels in the hamlets and villages, due to the underlying
low density.
In 2003 the Atlanta Regional Commission (ARC) awarded a Livable Centers Initiative grant
(matched by Fulton County) to the CHC to develop a high-density, mixed-use model village
plan. The design process, with considerable public participation, was completed in December of
that year. One tangible outcome was the incorporation of the southwestern corner of Fulton
County as the city of Chattahoochee Hills in 2007, providing home rule and greater local control.
In 2004, the PATH Foundation (which has helped create 160 miles of trails in Georgia) produced
a 98-mile, four-county regional greenway plan to designate protected corridors linking existing
greenspaces (county, state and private parks). Additionally, a study group from Georgia Tech
ranked individual parcels in terms of their significance as productive cropland or pasture,
watershed land (including riparian buffers and wetlands), and scenic parcels, including those
with vernacular architecture and historical or cultural significance.
The city’s zoning, adopted in 2007 (very similar to that adopted by Fulton County in 2002 for the
CHC region), allows for villages of 1,200 or more acres to be developed at a density of up to 30
units per acre, in certain areas. The TDR mechanism is available to help developers achieve the
higher village densities, thereby protecting equivalent acreage elsewhere in the city. The City
zoning also allows lower density hamlets (which is Serenbe’s zoning class) at a base density of
one dwelling per acre. Hamlets must encompass at least 200 acres (and therefore must provide at
least 200 dwellings), and their design must preserve 70 percent of their land. As with villages,
hamlet density can also be increased by using TDRs to shift development from any rural part of
the city.
As of early 2014, the TDR program had not become active and, looking forward, seems to have a
structural problem. According to Mike Morton, staff planner at Chattahoochie Hills, “The
demand for additional density that would necessitate a developer’s participation in the TDR
program will come late in the development cycle. This would allow sensitive property to remain
unprotected for a dangerously long time. The DTCs could be paid by the developer as the lots are
developed, providing a funding source for the TDR program much earlier in the development
cycle.” (email from Mike Morton, 8.24.12)
Figure 22-3.2: Illustrating the community’s vision of three mixed-use villages surrounded by farmland and forest, the
Chattahoochee Hill Country community master plan encompasses 40,000 acres of cropland, pasturage, stream valleys, and
woodland habitat. Rural protection buffers around each of the compact development areas (shown as tan ovals) serve as
growth boundaries, limiting the areal extent of the higher density villages and lower density hamlets. Serenbe is located along
the southern boundary, slightly east of center. Note: This master plan preceded the municipal incorporation date and
encompasses a larger area than the city’s eventual corporate boundaries. Riparian buffers are shown in green and form the
basic framework for a greenway system The gray areas include a number of existing subdivisions, but most of the land in this
color is proposed to be preserved through TDRs. Source: Pond & Co.
Results of a 2008 tree inventory, using GIS and GPS technology, concluded that each year
Serenbe’s woodlands sequester 52,700 tons of carbon every year and store 1.3 million tons of
carbon over the lifetime of each tree. Its trees also remove nearly 1,500 tons of air pollutants per
year from the air through carbon dioxide uptake in the photosynthesis process. Put another way,
Serenbe’s trees sequester the equivalent of 7,213 cars’ carbon emissions every year, and provide
long-term storage for the equivalent of 182,717 cars’ annual emissions.
Hamlet Design
The unique omega-shapes of three of Serenbe’s four hamlets, designed by Prof. Phillip Tabb of
Texas A&M University, respond to the contours of the land and maximize the green edges of
the development footprint, bringing nature into the heart of each hamlet. Development intensity
and mixtures of uses are greatest in the hamlet centers and feather out in a traditional concentric
manner. Rural protection buffers will contain the villages and prevent development from
spreading out into the land around them (Lerner, 2003)
Although the four hamlets share a similar mix of detached and attached dwellings, each is
planned to have a distinguishing character of its own. Selborne Hamlet emphasizes visual and
culinary arts, while the focus of Grange is farms and horses, featuring a tack shop, feed and seed
store, arts and crafts studios, and a barbecue restaurant. Mado, named for a Creek word meaning
“things in balance”, will be oriented to health and wellness facilities such as the destination spa,
an upscale boutique hotel, vegetarian restaurant, juice bar, and traditional and holistic medical
services, and the Hill Hamlet will boast retail (including a grocery), the post office, and the fire
station. All four hamlets will be connected by roads, trails, and bridle paths.
In Selborne, the first hamlet under construction, 90 percent of homes were completed by early
2012, including a live/work component with a dozen shops, although retail and offices had not
yet begun. Building at Grange began in 2007. Mado is planned and approved, and Hill, the fourth
hamlet, is still in the conceptual stages.
Figure 22-3.3: Schematic drawing and aerial photo of Selborne, the first of four hamlets at Serenbe. Situated at the edges are a
school, soccer fields, a wildflower meadow, a chapel, and the constructed wetlands sewage treatment facility. Sources: Map by
Phillip Tabb. Photo by Serenbe Development Corp.
Figure 22-3.4: Extensive conservation areas preserve Serenbe’s rural character and productive farmland. Source: Simmons
Buntin