One-Star Certified Pilot Project
Location: Washington, D.C.
Project Size: 0.77 acres
Project Type: Institutional / Educational
Site Context: Urban
Former Land Use: Greyfield
Terrestrial Biome: Temperate Broadleaf & Mixed Forests
photo by: STUDIO39
The Square 80 Plaza at The George Washington (GW) University replaces an existing parking lot and service alleys with an urban plaza, expansive lawn, ornamental tree grove, extensive pedestrian network, and an outdoor classroom for GW’s new Sustainable Landscape program. Using multiple low-impact development (LID) techniques, the project targeted 100 percent of all stormwater runoff to be retained on site. Sustainable project elements include: biofiltration planters, native plant material, pervious pavers, and cisterns and rain barrels to capture overflow water and roof runoff for irrigation purposes and for use in the sculptural water feature. Finally, the design includes the use of a rain garden and bioswale filtration in between the two residence halls.
Square 80 Plaza is an infill site located within Washington D.C. with soils considered by the Natural Resource Conservation Service (NRCS) as “Urban Land”, which is predominantly created fill material. GW's Foggy Bottom campus is located within the watershed of the Potomac River. The fact that this area has a combined storm and sanitary sewer system made stormwater management a priority environmental consideration. Washington DC falls within the USDA Plant Hardiness Zone 7b.
SITES Features + Practices
Notable sustainable features include biofiltration planters, native plant material, pervious pavers, cisterns, rain barrel, and sculptural fountain designed to reuse captured water.
In addition, particular strategies for this project include an emphasis on attaining water-related credits foremost, with human health and well-being, and soil and vegetation categories as complementary objectives.
The intention for the design in relation to the stormwater management was to retain as close to 100% of all run-off on site as possible. The stormwater would then be reused on site for irrigation and a sculptural water feature at the center of the plaza. In order to accomplish this, the site has three large underground cisterns totaling 33,000 gallons to collect the water for irrigation use. The water is gravity fed into a large irrigation well where it is treated and cleaned with a UV filter. A series of different methods were implemented in order to collect the stormwater such as pervious pavers, trench drains, vortex filters, and overall site grading.
The regional rainfall amounts were considered when sizing the cisterns. Our studies showed that for the lawn panel only we needed 30,000 gallons of water to irrigate in the driest months. We also incorporated native plant material that was indigenous to the mid-Atlantic region. We considered sourcing construction materials that were in close proximity to our region.
Clay brick pervious paving for sidewalks played a major role in our project goals for sustainability. The vortex filters were a unique and effective way to clean stormwater run-off from hardscape surfaces.
The integrated design team process helped define the project goals. GW wanted to create an "outdoor classroom" for its new Sustainable Landscape Design program, and to have a showcase piece on the urban campus that reflects the goals of the newly created Office of Sustainability. Listening to the needs of the students and other stakeholders helped in defining the different zones of activities within the plaza.
In addition, The District of Columbia mandates that all sites retain close to 100% of all stormwater on site. This code is in direct response to the fact that the majority of the City's stormwater lines are combined with their sanitary lines, and that the combined sewer system is taxed during heavy rain events. The National Pollutant Discharge Elimination System (NPDES) permit imposes monitoring and reporting requirements for total suspended solids, arsenic, iron, silver, copper, oil, grease, pH, and total residual chlorine.
Materials used on-site were chosen for their durability and low maintenance. The natural materials such as clay brick pavers and granite stone duct require no additional sealants or maintenance requirements; most of the materials selected are inert to minimize contribution to the stormwater pollution.
Maintenance + Stewardship
The Square 80 Plaza is intended to be an outdoor classroom for its users. Since its inception, the site has installed educational signage around the site to help educate the users on sustainability. The site has also impacted the surrounding community by acting as a catalyst for its newly adopted GWater Plan, consisting of four major focus areas: potable water, rainfall capture, wastewater, and bottled water. The GWater Plan documents GW's commitment to reducing potable water footprint and the negative impact on our watershed.
It is in the University's best interest to make sure that the goals for the plaza are upheld and that the stakeholders of the site still utilize the space as an intended campus amenity. Therefore, GW has created a maintenance and management plan that will be adhered to throughout the life of the project.
The site's performance, in regards to users, was monitored by student interns who spent a full day evaluating the human use of the site, including: activity within the site, user interaction, use of way finding, sustainability education, and social interaction as well as mental restoration. Along with observation, a post-occupancy evaluation survey was handed out, questioning users of the effectiveness, usability, and feeling of the place.
In regard to the performance of the main goal, which was to retain and reuse as close to 100% of stormwater run-off, the irrigation system is constantly being monitored to ensure functionality and that the water is still being cleaned by the various filtration systems. Bioretention planters with recycled rainwater fountain
Constructing a new urban plaza within the urban grid of a large metropolitan city. The courtyard is surrounded by existing buildings which made access and staging difficult.
Project Goals + Successes
One of the primary goals for the design team was to provide a sustainable project that would function in part as an "outdoor classroom" for the new Sustainable Landscape Design program GW is implementing. The design was also a reflection of the University's desire to create a more sustainable environment within the overall campus design.
The motivation to pursue SITES certification was driven by the benefits of exposure to the Sustainable Sites Initiative program to both administration and future environmental design students within the context of an academic institution, while assisting with the refinement and “trial” goals of the pilot effort. With the criteria set forth in the checklist, the SITES certification format influenced the project in regards to progress monitoring and documentation of design ideas.
The project team sees Square 80 Plaza as a success by the amount people that are now able to use the site for various activities. The site has been transformed from a parking lot into an oasis within the urban context that students use for recreation, outdoor classrooms, studying, reading, and dining.
Ensure that the site has been surveyed completely, including a geotechnical survey, all existing utilities, topography and soil conditions, before the start of design. Having this knowledge prior to design could have helped significantly with the designs and ultimately the certification of the site. It is also key to ensure that the contractors know and understand the importance of documenting where everything is sourced.
STUDIO39 Landscape Architecture
Dan Dove, RLA, LEED AP, Project Manager
Siobhan Chewning, NCARB, AIA, LEED AP, SITES Coordinator
Evan Timms, Landscape Designer
George Washington University
Adele Ashkar, ASLA, Director, GW Sustainable Landscape Design Program
Michael Burns, AIA, LEED AP, Project Manager, Campus Development Management
Nancy Giammatteo, AIA, LEED AP, Director, Facilities Planning and Design Review
Mark Stires, PE, Civil Engineer
Steve Wohlschlegel, PE, LEED AP, Electrical Engineer
Irrigation Consultant Services, Inc.
Carey June, CID ASIC
Donohoe Construction Company
Tim Loftus, Project Manager