A 33-acre brownfield area, now known as Justison Landing, is part of a comprehensive riverfront revitalization that has transformed derelict industrial lands of south Wilmington, Delware along the Christina River. Native plants and their cultivars were specified for the bioswales, a stormwater management feature designed by Oasis Design Group to address urban runoff water and promote infiltration. See the "Stormwater Management Plant Diagram" for the plant palette.

For more than half a century, downtown Wilmington, Delaware (pop. 70,851) was separated from the Christina River by industrial development. Wilmington, just southwest of Philadelphia, is on the left bank of the Delaware River. Just south of downtown at East 7th Street Park, the Christina River and Brandywine Creek converge to flow into the Delaware.

The land along both sides of the Christina River is flat, low-lying and marshy in places. The riverfront area was once home to shipyards and tanneries. Over time, the area became polluted and neglected.

The landscape architect's master plan shows the placement of Harlan Park at the edge of the Christina River, the pathways, curvilinear retaining walls and the transition to Harlan Plaza (top).

The Riverfront Development Corporation of Delaware www.riverfrontwilm.com targeted a 33-acre brownfield area, now known as Justison Landing, as part of a comprehensive riverfront revitalization that has resulted in the transformation of the derelict industrial lands of south Wilmington along the Christina River. A key objective of the project was building housing to support the new riverfront commercial, office and retail development, housing that would give people the opportunity to live, work and play in a compact riverfront urban environment. Justison Landing is the largest urban redevelopment project in the city of Wilmington since World War II.

Clay bricks (Pine Hall Brick) patterns along the concrete promenade are an attractive contrast. The circular steel sculpture ("Back to Back") by artist Joe, illustrates one of Oasis Design Group's philosophies"?ucombine art and horticulture in the landscape to create memorable places.

Scope of Work
Oasis Design Group, a landscape architecture, urban design and master planning firm in Baltimore, Maryland collaborated with engineers, architects, developers and state and city agencies to refine a new street grid of 12 city blocks. Oasis' planning work included configuration and size of development parcels; establishment of street right-of-ways; strategic location of public open spaces and plazas; and people-friendly linkages to the river and the existing Riverfront Wilmington development.

In addition to conceptualizing the overall urban design plan, Oasis designed and detailed more than 2.4 miles of urban streetscapes, creating a strong urban street scene with a hierarchy of streetscape treatments. The most intensely designed and highest-grade materials were used at the core of the development. Central to the project and at the heart of the development is a plaza and open space. Harlan Plaza was conceived to function much like an Italian piazza (city square), with vehicles playing a subordinate role to pedestrians.

Harlan Park, the associated green space, connects the plaza to the Christiana River and an existing riverwalk. The riverwalk was designed by Land Design Research International in 1998. The project manager was Scott Scarfone, ASLA, when he worked for LDR. Scarfone is the founder and principal of Oasis Design Group.

The Wilmington fire marshal required a 12-foot wide fire lane in a space between the Harlan Plaza and Harlan Park for access to an adjacent building, a route that unfortunately went through the spine of the park. The solution was reinforced turf panels ("Grasspave2', Landscape Structures) with bordering granite and clay brick pavement patterns. Another design limitation was a combined sewer outfall running underneath the linear park.

Harlan Park
The 1.5-acre Harlan Park is at the center of Justison Landing. Harlan Park was designed as the hub of Justison Landing, connecting Harlan Plaza to the west and the riverwalk to the east. The park was designed as a passive space, centrally located to host community events, or just a place to unwind or meet friends.

Several challenges presented themselves to the design team during planning and construction. First, the entire linear park is over a combined sewer outfall (CSO) that functions to drain Wilmington's stormwater to the Christina River.

• A subterranean concrete chamber measuring 6 x 10 feet, and at a depth of 2-3 feet below grade to the top of the chamber, was ever present. No significant loading, structures, or trees were allowed on top of the CSO.

• The fire marshal required a 12-foot wide fire lane to an adjacent building, which just happens to be the central open space and spine of the park. Thus, a reinforced fire lane had to be incorporated into the design. These two major constraints established the primary form of the park.

• Lastly, much of the soil over the park was contaminated and had to be remediated.

A grand lawn (fire lane) and sculptural terraces transition the 3-ft. grade change from the plaza and main park area to the existing riverwalk. The grade change was taken advantage of to create a small amphitheater open to the east, creating a spectacular view down the Christina River. These elements, among others, provide visitors with places to play, relax and enjoy riverside views.

Harlan Plaza
Harlan Plaza is the ceremonial heart of Justison Landing, a transition from the dense urban development planned for Justison Landing into Harlan Park and connecting to the Christina River. Bisected by the roadway, the plaza includes the Harlan Boulevard and Justison Street intersection as an integral part of the plaza. The raised intersection (table top) is a traffic-calming measure paved with granite and extensive patterns to give the plaza a traditional European flair. Adjacent plaza edges were designed in close collaboration with the building architect to create separate but adjoining spaces to accommodate small outdoor caf????(R)???(C) dining or gateway plazas to building entrances.

The core of the pedestrian plaza is an open space with two flanking, adjoining pathways. Lined with at-grade planters and flowering trees, the corridors are short promenades with benches on both sides of the way. The plaza opens to the east to the open lawn area of Harlan Park. As with the design of the park, the plaza had to maintain an open central pathway free of obstacles to accommodate the fire lane and subterranean CSO. The plaza design is an attractive, clean design using high-quality and enduring materials, mainly granite with clay brick accents.

Dense, colorful swaths of native plantings (Juncus, Eupatorium, Rhus, Hibiscus, Panicum, among others) provide seasonal interest throughout the year and give people the impression of a garden, which masks the area as a stormwater management facility.

Building the Project
Construction for the 33-acre site included all of the new streets, sidewalks, open spaces and infrastructure to accommodate the new development parcels. Several parcels were developed by the developer concurrent with the project infrastructure. Other land parcels were designated at that time, yet they'll be developed in the future as the market allows. Oasis Design Group worked closely with Delaware Department of Transportation, Rummel, Klepper & Kahl and its construction manager to oversee construction of phase one. Oasis Design Group's role in this phase included handling contractor requests for information, attendance in regular construction progress meetings, reviewing submittals and shop drawings, and construction observation.

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Stormwater Management Plant Diagram
shrubs
fg - "Blue Mist' Fothergilla
it - Itea virginica (Virginia Sweetspire)
ru - Rhus aromatica (fragrant sumac)
rz - Rosa "Radrazz' ("Knock Out' roses)
tb - Taxus baccata ("Repandens'dwarf English yew)

Perennials
bap - Baptisia australis (false Indigo)
eum - Eupatorium coelestinum (hardy Ageratum)
hhp - Hemerocallis "Mini Pearl' (daylily)
hlb - Hibiscus "Lord Baltimore' (rose mallow)
lia - Liatris spicata (button snakewort)
sol - Solidago rugosa "Fireworks' (rough Goldenrod)
shs - "Helene von Stein' lamb's ear
ver - Vernonia noveboracensis (New York ironweed)

groundcover
lrm - "Big Blue lilyturf

grasses
car - Carex stricta (Tussock sedge)
cha - Chasmanthium latifolium (northern sea oats)
jef - Juncus effusus common rush
pan - Panicum virgatum "Shenandoah' (switch grass)
pal -dwarf fountain grass

Economic Revitalization and Funding
Justison Landing is now a vibrant, urban mixed-use riverfront community where people live, work, and play"?ua model for how urban riverfronts can be rediscovered and returned to productive urban land. Justison Landing began development in 2005. It is phase one of a $500 million project that encompasses about 260 condominiums, 50 townhouses, 184 loft units, 196 apartments, 98,000 square feet of retail space and 300,000 square feet of commercial space.

Public investment in the Riverfront District was leveraged by the Riverfront Development Corporation of Delaware to attract private investment, establishing the Riverfront as an economic engine for job growth and a growing source of tax revenue. Between fiscal years 1996 and 2007, Riverfront Wilmington received more than $270 million in public funds from city, county, state and federal agencies to finance public investment projects, as well as $617 million in private development. To date, land parcels are continuing to be developed; for example, a new movie theater and hotel were constructed in 2012.

At the west end of Harlan Plaza, a smaller flanking brick-and-granite plaza is the setting for a building entrance. The space is enclosed and separated from the intersection by a raised-granite planter with ginkgo trees.

Project Team
Client: Delaware Department of Transportation
Landscape Architect: Oasis Design Group
Engineer: Rummel, Klepper & Kahl
Granite Supplier: Cold Spring Granite
Brick Manufacturer: Pine Hall Brick
Brick Distributor: Delaware Brick Co.
Mason Contractor"?uFlatwork/Paving: GrassBusters Landscaping & Irrigation
Construction Manager: Pettinaro Co.
Master Developer: Riverfront Development Corp. of Delaware
Private Parcel Developer: Buccini/Pollin Group