Canal Park

In 2004, a design competition was held and design development on the park began. Nearly four years later, the rapidly transitioning neighborhood surrounding the park contained many new businesses and stakeholders that had not been part of the original design process. The surrounding community strongly supported a redesign of the park, and in 2008, a Request for Proposals (RFP) was issued that included several criteria required for a new park design. The park needed to attract visitors from around the city while retaining the interest of the local residents and numerous day-time office workers who were crucial to keeping the park active. The design would need to serve people of various ages, and diverse social and economic backgrounds, while also providing a connection to the canal’s historic legacy. Year-round activity was important, as well as keeping the park active at all times of the day and promoting public safety. Environmental sustainability was a priority, with a goal of incorporating renewable energy and developing an innovative stormwater management system that considered runoff from surrounding buildings not yet built. Operation and maintenance would be crucial for the continued success of the park and had to be considered in design due to the limited budget available for this purpose. Designers were facing a difficult challenge, attempting to create a park for a neighborhood and users who were anticipated in the future, but did not yet exist.

As part of D.C.’s Anacostia Waterfront Initiative, one of the park’s main objectives was to retain and treat stormwater on-site, improving water quality and reducing the volume of flow to the nearby Anacostia River which suffers from combined sewer overflows during heavy rainfall. Creating a comprehensive stormwater management system for the park was a complex task. One of the proposed components of the system was the reuse of runoff from the contaminated site in interactive fountains where users would be in direct contact with the recycled water. At the time, there was no precedent for this use of recycled water in high exposure areas, and existing city regulations did not provide standards for end-use water quality.

Solution

To address the RFP criteria, a linear rain garden and water feature running the length of the park evoked the site’s historic canal and three pavilions located within the park suggest the floating barges that were once seen in the canal. Flexible spaces and amenities such as movable seating were included to accommodate different activities and special events, and have the ability to adapt over time. An interactive fountain that transforms into an ice rink in the winter attracts users year-round while plantings provide seasonally changing hues. The park restaurant with outdoor seating provides activity into the evening and lighting was carefully designed to promote nighttime visibility. Geothermal wells reduce energy use and a comprehensive stormwater system collects, filters and stores site runoff for reuse. The stormwater system was designed and sized to collect not only all rainwater falling on the site but also the roof runoff from the future development of several different parcels adjacent to the park. To ensure the longevity of the park, a park maintenance and management plan was developed.

The design team performed an extensive risk assessment of the site and collaborated with the District Department of the Environment (DDOE) to develop end-use water quality standards for the system. This collaboration led to the DDOE adding an appendix to their Stormwater Management Guidebook to address the issues raised by this case study. The appendix provides a process for evaluating the risk to human health based on collection area and possible exposure. Due to the innovative stormwater filtration and reuse system, the DDOE also considers the park a demonstration project that can be used as a model for future projects with similar goals related to stormwater management and green infrastructure.

• A 6,000 sf series of linear rain gardens and 46 bioretention tree pits around the perimeter of the site capture, detain, and treat stormwater runoff. 
• 2 underground cisterns located under the south block hold up to 80,000 gallons of water collected from the park and neighboring streets.
• 2 interactive water features, one with 42 programmable water jets and the other a 20-ft by 135-ft thin skim of water, utilize stormwater runoff captured and treated on site.
• A 10,000 sf seasonal ice skating rink provides a 250-ft linear path for skaters on the southern block of the park and is supplied by treated stormwater runoff.
• The treament system for the reused stormwater targets contaminants identified as potential risks.  A combination of bioretention, filtration and ultraviolet (UV) disinfection are used to reduce concentrations of total suspended solids (TSS) to 0.14 mg/L and to remove 100% of biological pollutants.  To maintain quality, water in the system is tested weekly and only organic, biodegradable products are used to maintain vegetation on-site.
• 3 pavilions, one in each block of the park, are designed to evoke the floating barges that were seen in the Washington City Canal that once ran through the site. The 2 smaller pavilions, approximately 200-sf each, provide a stage on the middle block and storage for park amenities.
• Located in the southern block of the park, the main pavilion is 9,000 sf and contains a 65-seat full-service restaurant with additional outdoor seating, a skate rental booth, and utilities supporting the park and ice rink. On the top of the pavilion is a 1,200 sf accessible vegetated green roof and light cube with 20-ft by 20-ft panels that can project art images, light shows, or videos.
• 28 geothermal wells, located below the skating rink, reduce energy needed for park utilities and to heat and cool the main pavilion.
• The park is located within 1/4 mile of a Metro station with 9,500 average daily riders and 4 Capital Bikeshare stations. 39 bike racks are provided on the site.
• 2 dual charging stations provide 4 charging ports for plug-in electric vehicles, with each port supplying 7.2 kW of output power.
• 80 energy efficient lighting elements throughout the park provide a safe space for nighttime activities while minimizing electricity use. Vertical illuminance levels surpass the 10 lux minimum recommended for pedestrian zones. 
• 3 interpretive signs, one on each block, provide information on the park’s sustainable features and the history of the site.
• 3 sculptures by artist David Hess serve as interactive play structures. They were built with 4-in stainless steel metallic tubing to create large curving lines that recall the continuous motion of water.
• Flexible spaces and amenities throughout the park include open green spaces, a children’s play area, and 25 movable tables with chairs and umbrellas. They are used for a variety of programs and events.
• Over 150 trees and hundreds of shrubs and flowers are found within the park. The linear rain gardens are planted with a range of native and adapted species transitioning from woody shrubs and trees at the northern end, to shallow herbaceous plants in the south.
• 60,000 sf of high albedo unit pavers were used in the park to decrease the urban heat island effect and allow for easier maintenance.
• 100% of the wood used to construct the benches, bridges and pavilions was obtained from forests certified by the Forest Stewardship Council (FSC).
• Over 50% of all materials, plants, and soils for construction were manufactured or grown, and extracted or harvested within 500 miles of the site.
• Raised ‘table-top’ intersections were created to prioritize pedestrian safety on the 2 streets that bisect the park by extending the park paving materials across the street to create an uninterrupted surface.
• Streets through the park were narrowed from 33 ft to 22 ft and curb bump-outs were added to the surrounding intersections to slow vehicular traffic. The bump-outs decrease the length of crosswalks by as much as 15 ft, allowing pedestrians to cross the street 40% faster.

In order to achieve a Three-Star level of certification under the Sustainable SITES Initiative Pilot Program, Canal Park had to receive a minimum of 150 points. To reach this goal, one of the credits chosen to pursue was Credit 9.1: Monitor performance of sustainable design practices. The intent of this credit is to “monitor and document sustainable design practices to evaluate their performance over time and improve the body of knowledge on long-term site sustainability” (The Sustainable Sites Initiative: Guidelines and Performance Benchmarks 2009, p. 210). To achieve this, at least three eligible credits must be monitored and the results documented and communicated to the field. The landscape architect and design team leader for the project (OLIN) chose to monitor the performance of three credits that fall under the Human health and well-being category of SITES certification:

• Credit 6.5: Provide for optimum site accessibility, safety, and wayfinding
• Credit 6.7: Provide views of vegetation and quiet outdoor spaces for mental restoration
• Credit 6.8: Provide outdoor spaces for social interaction

The project had documented and acheived these three credits, for a total of 10 points towards certification. In order to receive an additional 10 points, each of these three aspects of the design had to be monitored for a minimum of six months after project completion and site occupation. OLIN chose to focus on monitoring the social performance of the park not only to achieve certification points, but to also obtain a more in-depth understanding of how the park was functioning for people. They went beyond the required monitoring so that they could explore a broader range of social metrics to evaluate performance, develop their in-house social research capabilities for use on future projects, and make a contribution to the knowledge of social performance within the field of landscape architecture.

An in-depth post-occupancy study of the park was conducted by OLIN over a year-long period from May 2013 to April 2014. The study was designed to measure the performance of the three SITES credits and to answer questions posed by the design team about how specific design features might support social functions and questions posed by the client about how the park was functioning for visitors. A variety of methods were utilized to provide a wide range of information on park operation and performance, as well as visitor use and perception. Interviews were conducted with key park stakeholders and a survey was developed and administered to visitors on-site. Environmental monitoring of light and sound levels was conducted and hourly weather conditions were recorded. On-site observations and time-lapse photography of the park activity supplied additional information to support data collected through surveys.

The evaluation provided important quantitative and qualitative information about park visitors and insights into their use of different design features. In addition to helping the park achieve a Three-Star level of SITES certification, this monitoring has provided a wealth of knowledge about the park’s social performance. The information gleaned will inform OLIN’s future designs and advance the field of landscape architecture.

• The total cost for wood-based materials used in construction of the park was $269,500.  All of the wood products were obtained from responsibly managed forests certified by the Forest Stewardship Council (FSC).  The price of FSC-certified materials is generally estimated to be 10 – 20% more than conventional wood products, which meant a cost increase in the range of approximately $25,000 to $45,000 for the project.  Although the cost was higher, the use of FSC-certified wood promotes the health of the world’s forests and provides environmental, social, and economic benefits beyond the site.
• Reusing stormwater collected on-site for landscape irrigation, park fountains, and the ice skating rink provides an annual cost savings of $4,600.  If treated stormwater was also used for toilet flushing in the park pavilion, instead of the conventional city water, the annual cost savings would increase to $5,400.  If the system is able to collect additional stormwater from off-site roof area in the future by connecting to all new development on adjacent parcels, and reuse stormwater for toilet flushing, the cost savings could be as much as $8,400 annually. 
•  Unit pavers were utilized instead of cast-in-place concrete for the majority of the park’s hardscape to allow for easier maintenance. The total cost for the pavers was $108,000, approximately 5% more than the estimated cost of using poured concrete. Although the pavers were a higher initial expense, the cost for ongoing maintenance is approximately $2 to $7 per sf less than poured concrete, offering significant long-term savings for the project.

• In order to create continuity across the three separate blocks of the park and slow vehicular traffic, ‘table-top’ crosswalks were utilized on the streets that bisect the park. Observations on-site found that drivers did demonstrate more caution while proceeding through the crosswalks and pedestrians appeared more comfortable crossing the street. While the design did appear to meet the goal of creating a more pedestrian-friendly environment, it also caused a problem for parents of young children who did not understand the crosswalk was part of the street. Several parents surveyed at the park revealed that their children had run out into the street because there was no curb to indicate where they should stop. Despite the concerns, no injuries have been reported, however, the findings do provide important information for consideration in future designs. 

• The park’s stormwater system was designed to provide treated runoff for toilet flushing in the pavilion, and was sized accordingly. When the park first began operation, the toilets were using reclaimed water as planned, however management received constant complaints from the public regarding the “dirty” appearance of the water in the toilets. Despite their best efforts to explain this sustainable practice through signage and other methods, public dissatisfaction remained high and park management decided to return to the conventional method of using city water in the toilets. In addition, the park’s stormwater system was also designed to connect to adjacent parcels as they were redeveloped over time. This integration would allow the system to collect additional stormwater from off-site sources, making more water available for reuse in the park. Since the park was completed, the parcel to its north was redeveloped, but the renovated building was not connected to the stormwater system due to budget constraints. Another parcel at the northwest corner of the park is currently being redeveloped, but at this point, there is no indication it will connect to the park’s system when it is completed. These discrepancies between the way the stormwater system was designed and the way it is currently performing demonstrate that no matter how well a feature is designed, public perception and economic circumstances can still play an important role in how sustainably it will perform. 

• The southern block of the park required a large open area of hardscape for the ice skating rink, which prompted concerns over a lack of shade available in the summer months. The designers originally planned a shade structure over the area, however, the client decided against it. After the park was built without the structure, the open area was often too hot for visitors to be comfortable and the few shaded areas lacked sufficient seating. The client added movable tables, chairs, and umbrellas to address the lack of shade and accommodate the additional lunch crowd spurred by food trucks parking along the southern edge of the park. These features provide needed shade and additional seating capacity, and appear to be well used by park visitors. This is a good example of how small design adaptations made after a project has started operating are sometimes necessary to better meet the changing requirements of the users.

• During the design process, the landscape architect looked at several other parks as precedents. The children’s grassy play area in the middle block of Canal Park and the Bosque in the north block were modeled after similar successful features in other parks. However, in Canal Park, these features are not being used in the ways expected. In the middle block, the water feature exhibits much heavier use by children and parents than the designated play area. At the north end of the park, the Bosque envisioned as a flexible seating area is largely unused due to the lack of moveable tables and chairs, and less pedestrian traffic through the block. This demonstrates the limitations of using precedents in the design process, and how use of a space is influenced by context.

• The client’s original goal for the design was to create a zero-energy park that demonstrates modern sustainable strategies. While the park was not able to achieve the ambitious net zero goal, the client project manager maintained a strong push for integrating sustainable features into the design throughout the process. The landscape architect found that having a client supportive of sustainability was helpful in both the complex design process and in the documentation process necessary for SITES certification.

• Although the park is well-used throughout all seasons, the heaviest use seems to coincide closely with more intense programming. For example, large numbers of people are attracted to the park during the weekly outdoor movies and noontime concerts in the summer and when the ice-skating rink is operating in the winter. To stimulate more equal year-round use, future programming could be implemented to specifically target the seasons exhibiting lower numbers of visitors, especially fall.

• The park creates a local public open space for residents and workers. Survey data showed that 36% of visitors surveyed traveled two minutes or less to reach the park, 67% traveled five minutes or less, and almost 80% traveled ten minutes or less. The park is also a destination for the wider area, particularly in winter with the ice skating rink.

Unit paving manufacturer: Hanover Architectural Pavers
Stormwater reclaim system: AMES, Inc.
Electric car charging stations: ChargePoint
Greenroof: American Hydrotech Garden Roof Extensive Assembly
Wood for benches, bridges, and pavilions: Black Briar Farms
Pedestrian light poles and bollards: Hess America
Catenary lights: BK Lighting

Project Team

Client: WC Smith
Landscape Architect: OLIN 
Architect: Studios Architecture 
Civil Engineer: Vika Capitol, LLC 
Civil Engineer: Nitsch Engineering 
Structural Engineer: SK&A Structural Engineers, PLLC 
MEP Engineer: Joseph R. Loring & Associates, Inc. 
Geotechnical Engineer: Soil Consultants, Inc. 
Environmental Consultant: Environmental Consultants and Contractors, Inc. 
Environmental Design & Lighting Design: Atelier Ten 
Irrigation Design: Lynch & Associates, LTD 
Sculptor/Public Art: David Hess 
Ice Rink & Fountain Design Engineer: Bonestroo 
Signage Content: Cultural Tourism DC 
Cost Estimating: Davis Langdon 
Public Space Management: ETM Associates, LLC 
Commissioning Agent: Advanced Building Performance (ABP)
General Contractor: James G. Davis Construction Corporation

Role of the Landscape Architect

The landscape architect led the large design team and worked closely with the client to create an integrated, sustainable solution on a challenging urban site with limited space. Sub-consultants with experience in sustainable systems were selected and included several firms the landscape architect had worked with on previous projects to create the best possible design team. Close collaboration with the architect and other consultants during design and construction allowed for the creation of a seamless relationship between the landscape, buildings, and sustainable infrastructure and features on the site.  A special consultant was added to the team to assist with the creation of a park maintenance and management plan to ensure the longevity of the project.  Throughout the design process, the landscape architect also collaborated with the District Department of the Environment (DDOE) to develop quality standards for recycled stormwater to be used in the park’s interactive fountains.