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Potomac Science Center

Landscape Performance Benefits

Environmental

  • Saves 2,400 gallons of water annually by using harvested water to irrigate a 250-sf green wall. This is equivalent to a year of drinking water for 13 people.
  • Restored 9,280 sf of habitat along the Occoquan River with native plantings.
  • Sequesters 1,358 lbs of atmospheric carbon annually in tree plantings at the site. As of January 2021, trees on site are estimated to have stored 1,766 lbs of CO2 equivalent.

Social

  • Increased engagement with the Occoquan River, with 54% of 15 survey respondents reporting enjoying the view of the river during their visits and 39% engaging in ecological-based recreational activities like bird-watching and plant identification.
  • Provides educational value, with 100% of 13 surveyed visitors who were familiar with the site reporting that they noticed and learned about the green wall, rainwater harvesting system, and other water-related features. 62% felt that the “Water Story” features greatly enriched their learning experience at the site.

Economic

  • Helped to catalyze the awarding of $842,403 in research grants to projects headquartered in the Potomac Science Center in 2019. With new researchers moving into the Science Center, funding is predicted to increase.

At a Glance

  • Designer

    LandDesign

  • Project Type

    School/University

  • Former Land Use

    Greenfield

  • Location

    650 Mason Ferry Ave MS 4E3
    Woodbridge, Virginia 22191

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  • Climate Zone

    Humid subtropical

  • Size

    5.5 acres

  • Budget

    $32 million (building and landscape)

  • Completion Date

    2017

The Potomac Science Center (PSC), an extension of George Mason University, is perched on the bank of the Occoquan River in Prince William County, Virginia, and serves as the premier tidal freshwater research lab facility in the Chesapeake Bay Watershed. The original condition of the site was an open field that had previously been mass graded with pockets of low-quality woodlands on the fringe, including invasive plants and a very steep slope to the water’s edge that made it impossible to safely access the shore. The new 50,000-sf research facility houses laboratories for teaching and research, lecture halls, event spaces, and outdoor education areas that support PSC’s mission to sustain and improve the health of the freshwater ecosystem. The site serves as a showcase of low-impact development techniques, highlighted in the “Water Story” features that educate students and the public on the management of stormwater runoff on-site to protect water quality and aquatic habitat. Visitors actively engage with the landscape through educational programs hosted by the PSC in the upper courtyard and river-level plaza. Visitors can access the site through the Potomac Heritage Trail, appreciate the rain gardens and native plantings, and enjoy the riverfront views from the outdoor amphitheater or boardwalk.

  • In the arrival court, students, visitors, and staff are greeted with a weir and scupper water feature on the roof that directs runoff from a portion of the roof into a rain garden. 
  • A 5,000-gallon harvesting cistern captures rainwater from the office and lab building roofs, as well as condensation from the air conditioning system, and stores it for use in site irrigation.
  • A 250-sf green wall located in the river-level plaza is irrigated by water from the cistern. It serves as an educational feature, inviting the public to interact with the site and showcasing the site’s environmental goals in an artful manner.
  • The arrival court and many of the pedestrian paths and outdoor plaza spaces are surfaced with 5,574 sf of permeable pavers, which allow water to infiltrate through the pavement and into the subsurface.
  • A series of rain gardens and infiltration swales located throughout the site capture and filter runoff.
  • An accessible boardwalk was built along a portion of a previously-existing stormwater pond along with a platform that extends out into the pond. This boardwalk was designed to be as close as possible to the permanent water elevation of the pond to facilitate research and engagement with the water. 
  • A river-level plaza hosts university events, educational activities, and outdoor lab programming. A tabletop installation, coined the Water Table, was custom designed to replicate characteristics of a dry creek bed. This is used to engage learners in authentic stream restoration activities and teach the public about water quality, erosion, and the Occoquan River.
  • 6 outdoor teaching spaces can accommodate groups of up to 20 for educational programs.
  • The terraced outdoor amphitheater overlooks the Occoquan River. Its terraces and cast-in-place concrete walls stabilize the bank and help to mitigate erosion. Students and faculty use the outdoor amphitheater as a classroom and event space.
  • A rain chain artfully stands in for a traditionally closed gutter downspout, allowing visitors to see the movement of rainwater from the upper courtyard down to the river-level plaza. 
  • The site was designed to provide accessible access over the significant grade change from the research facility to the Occoquan River below, with 25 ft of grade change to the mean water level (the river experiences up to 8 ft of daily tidal fluctuation). This access is key to the Potomac Science Center’s mission as a research institution. A research dock on the river provides direct access to the water for samples, experiments, and excursions. An ADA-accessible switchback ramp along an elevated boardwalk winds through the riparian buffer down to the dock, connecting people of all abilities to the river.  
  • 65 species of native plants including trees, perennials, and groundcovers were selected for their appropriateness to the wider Potomac River ecosystem and ability to provide year-round habitat for local wildlife while adding visual interest to the site. With the exception of turf areas in the outdoor amphitheater and those required for fire lane access (approximately 1,268 sf), the landscape is made up of 100% native plants suited for the Occoquan River’s riparian environment. This includes approximately 10,000 sf of riparian buffer restoration planting, 10,548 sf of revegetated area, and 2,181 sf of shoreline restoration area. Highly visible plantings were sited near public spaces to encourage visitors to look more closely at the inhabitants of these living habitats. Plantings on-site include buttonbush (Cephalanthus occidentalis), ninebark (Physocarpus opulifolius) and meadowsweet (Spiraea alba).
  • Potomac Science Center is part of the George Mason University Arboretum. As of 2020, 5 tree signs have been installed to draw visitor attention to key tree species on-site.
  • The site directly connects to the Potomac Heritage National Scenic Trail, a network of trails that run through the Potomac Heritage corridor. This connection was integrated into the design of the site to allow uninterrupted access to the network of pathways. Trail users often stop at the Center to engage with the site, walk along the boardwalks, or sit in the amphitheater.
  • 12 bicycle racks on-site are available for use by visitors to the Potomac Science Center or Potomac Heritage Trail.
  • The Potomac Science Center is included as an integral component of a planned waterfront park included in Prince William County’s North Woodbridge Small Area Plan.

Challenge

  • Support the status of the Potomac Science Center (PSC) as the premier tidal freshwater research lab facility in the Chesapeake Bay Watershed.
  • Further the PSC’s educational and environmental mission to utilize scientific research, restoration, education, and policy analysis to help society understand and sustain natural processes in ecosystems, watersheds, and landscapes.
  • Improve the ecological quality of this formerly unmanaged field on the edge of the Occoquan River.
  • Educate the public on stormwater issues and solutions through a series of highly visible low impact development strategies.
  • Invite the general public to visit and engage with the outdoor landscape of the PSC campus and Occoquan River by incorporating and enhancing the connection to the Potomac Heritage National Scenic Trail.

The Potomac Science Center (PSC) is a public/private partnership between George Mason University (an agency of the Commonwealth of Virginia) and joint developers on privately donated land. The typical design challenges of the site were complicated by the diverse stakeholders involved. Not only was the intention for site usage slightly different for each stakeholder, but each stakeholder is also made up of many subdivisions — many of them siloed. This situation yielded lessons that could not be creatively solved during the design process. The following challenges were encountered as a result of the PSC’s shared ownership by multiple stakeholders with diverse operating procedures.

Challenge #1: Project Scope
Unfortunately, signage was not included in the scope of work for the landscape architect. The signage design and installation process was delegated to George Mason University, and it had not taken place as of March 2020 whereas site construction concluded in August 2017. Two factors have contributed to the delay in signage: 1) University signage standards were developed to guide the design of wayfinding signs, not educational/exhibit signage and 2) there is a lack of dedicated funding to complete the project. One of the core educational aspects of this site, the Water Story, has lost some effectiveness because the signage that explains the intent of the design features located throughout the site was not implemented. Including educational signage in the budget and scope of the landscape architect might have ensured that design elements like the Water Story were as impactful as envisioned.

Challenge #2: Shared knowledge and multi-stakeholder maintenance
Throughout this project, only key stakeholders had a full understanding of the intent and vision for the site Documenting the vision for the PSC campus in more detail early in the design process for communication to future collaborators and partners could have provided a consistent base of knowledge that would have benefited the design and construction process. The design firm recommended the creation of a site-wide maintenance manual to ensure the long-term success of the site design. No such manual was included in the final project. This has resulted in lost knowledge regarding the intent and function of site features. For example, many riparian protected area plantings along the stormwater pond died off due to lack of proper maintenance and irrigation. Furthermore, important maintenance guidance on how to maintain stormwater systems, such as the cistern or green wall, was never developed.

Cast-in-place concrete walls (including finishes) cost approximately one-third of the projected cost of gabion construction for the amphitheater. Cast-in-place walls also use more recycled materials than gabion walls, which consist of more raw materials.

  • Prince William County granted unique permitting circumstances for this project that allowed impacts to the riparian protected area (RPA). Some key interventions in the RPA that the design team advocated for were ADA accessibility for the research dock, an outdoor amphitheater that doubles as an erosion control system, and other features integral to the educational focus of the site. During the construction process, the State of Virginia’s Department of Environmental Quality (DEQ) intervened in opposition to the proposed impacts to the RPA. The landscape architect took the lead in negotiating with the DEQ to mitigate potential negative impacts to the RPA, and design changes were made to resolve the dispute and continue construction.
  • Some site elements were at risk of being value-engineered out of the project, but the landscape architect was successful at advocating for key components that were vital to the design intention. The educational focus of the site increased the project’s resiliency to the normal pressures of value engineering associated with “extra” features, such as the amphitheater, rain gardens, and water table.
  • The heavy pedestrian use of the outdoor amphitheater necessitated a more durable landscape surface. The turf grass at amphitheater steps was replaced with permeable pavers in May 2019.
  • Safety lights, which were required at the edges of the outdoor paths, attract a large quantity of spiders that coat the outside of the building. Additional maintenance is required to remove spiders before the space is used as an event venue. A birdhouse designed to attract purple martins has been installed with hopes of these insectivorous birds reducing the spider population.
  • Incorporating the pre-existing Potomac Heritage Trail into the site and maintaining connectivity presented some design challenges. The design firm worked with County stakeholders to incorporate the existing trail as part of the building and site design, amplifying the mission of the two entities by physically linking them. The Potomac Science Center and its landscapes provide a node of interest for trail users while the center’s educational mission benefits from foot traffic from the trail.

Pedestrian Permeable Paver: Hanover
Drinking Fountain: Haws Corporation
Bike Racks: Landscape Forms
Grasspave: Architectural Hardscapes, Inc.
Flexipanel Vertical Wall System: Sempergreen
Picket Railing: Hansen Architectural Systems
Trash Receptacle: Landscape Forms
Cistern: Water Storage Tanks, Inc

Project Team

Landscape Architect: LandDesign
Client: George Mason University
Developer: Belmont Bay
Architect of Record: HKS, Inc.
Associate Architect: ZGF Architects, LLC
Construction Contractor: EE Reed
Lighting Consultant: MCLA Inc. 
Partners: Prince William County, Prince William County Parks and Recreation

Role of the Landscape Architect

The landscape architect was responsible for all planning, design, and environmental services associated with the site, including: conceptual framework of the design; production of landscape architecture design; oversight of all landscape architecture construction; coordination with the project engineer and architect; LEED coordination; and federal, state and local permitting. 

Case Study Prepared By

Research Fellow: Cynthia B. Smith, Associate Professor, George Mason University
Research Assistant: MacKenzie Earl, George Mason University
Firm Liaisons: Stephanie Roa, Designer; Alison Peckett, Senior Designer, Lisa Biddle, Associate; LandDesign

To cite:

Smith, Cynthia B. and MacKenzie Earl. “Potomac Science Center” Landscape Performance Series. Landscape Architecture Foundation, 2020. https://doi.org/10.31353/cs1660

Topics

Water conservation, Habitat creation, preservation & restoration, Carbon sequestration & avoidance, Recreational & social value, Educational value, Other economic, Rainwater harvesting, Permeable paving, Bioretention, Native plants, Green wall, Educational signage, Learning landscapes

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