ASLA Recommendations for Integrating Sustainable Practices in the Mall's Renovation
Adapted from the original recommendations, issued March 2007
The American Society of Landscape Architects is a strong proponent of the principles of
sustainability supported by the policies of the National Park Service, and it is our belief that
no better demonstration project for those principles can be found than the National Mall. It is
in this context that we offer our commentary on plans for the National Mall in the twenty-first
ASLA, in partnership with the Lady Bird Johnson Wildflower Center at the University of Austin and the U.S Botanic Garden, is currently working to produce a site project tool, the Sustainable Sites Initiative, to help encourage and define sustainable landscape design practices. ASLA believes that the National Mall should be the exemplar for sites in America, and our comments reflect a set of criteria and goals that, if achieved, would bring those principles to life on the National Mall. Imagine if every one of the millions of visitors to the National Mall annually came away with a new or renewed awareness of the principles of sustainability. Such an experience and education could have a profound effect on the quality of our environments all across America. It is with this goal in mind that ASLA offers its comments to the National Park Service.
- The National Mall should be recognized as a cultural and civic landscape of international importance and, thus, its fundamental character should be preserved and enhanced.
- The existing tree canopy should not be reduced, but within the context of a cultural landscape report, be increased. With the exception of the elm and cherry trees, such a beloved part of the designed landscape of the National Mall, any new plantings should be native.
- Exotic and invasive species should be removed over time and replaced by native plants except in highly designed landscape areas. New plantings should avoid monoculture and maximize biodiversity and be appropriate for the surrounding environment.
- Plant communities that will encourage birds and wildlife habitat should be created.
- While the central lawn panel of the National Mall is a critical part of its cultural value, it should be interplanted with xeric, native grasses and should be maintained using electric mowers (or non-fossil fuel engines) and apply principles of integrated pest management for pesticides, herbicides, and fertilizers. It should be a goal to reduce maintained lawn areas in the National Mall that are not critical to the cultural hardscape and replace with native plantings or porous paving. No nitrogen or phosphates from any fertilizer should be permitted to runoff the area into the Chesapeake Bay Watershed and only organic fertilizers should be used.
- Beyond those already approved, no new museums, memorials, or attractions should be permitted within the core area of the National Mall. Such facilities should be proposed for adjoining urban areas within the District of Columbia that would benefit from that catalytic effort and become regenerated as a result.
- Minor landscape features, structures, or artworks may be considered to enrich the National Mall experience to the extent that they do not have a negative impact on the cultural or natural landscape, as determined by the National Park Service.
- Transportation on the National Mall should be primarily non-motorized-pedestrians and bicycles-with a strong provision for mass transit using energy other than fossil fuels.
- No additional provisions should be made in the future for lane capacity or surface parking for automobiles.
- A new, free, people-mover system should be provided within the National Mall area. Its route should be on existing streets and feature sheltered stops at quarter-mile intervals. Its energy source should be electric or other appropriate non-fossil fuel or renewable energy. Headways should be ten minutes or less to promote active use and to reduce vehicular trips.
- Traffic-calming devices including but not limited to speed tables and paved crosswalks should be added to increase pedestrian safety.
- Stormwater runoff from the National Mall should be reduced and its quality should be improved through natural filters, including rain gardens and bioswales where possible.
- No additional impervious surfaces should be introduced into the ground plane of the National Mall without an equal reduction elsewhere. Porous pavements, both solid and granular, should be used. A goal should be set to reduce the impervious pavements from the current state by 25 percent over time.
- Rainwater should be harvested for any irrigation systems or grey water should be used. Potable water should not be used for watering of plants or lawns.
- Remaining native soils should be preserved and enhanced through erosion control, removal of contaminated soil, and organic amendments, for the healthy cultivation of plants and soil organisms that are a part of the food chain. In cases where native soils no longer exist, soil condition should be improved by reducing bulk density and soil compaction.
- Critical root zones of major trees, especially the elms and cherries, should be protected from construction and human activity. While celebrations, festivals, and marches on the National Mall should continue to enrich our lives, adequate aeration and infiltration of the soils within the critical root zones must be maintained and improved.
- Universal access and design should be provided throughout the National Mall.
- An appropriate hierarchy of exterior lighting should help to support the principles of dark sky regulations, and a minimum of one-half footcandle illumination should be provided on major walkways for safety.
- New restroom and concession facilities should be located throughout the National Mall area such that all areas are within a quarter mile or a five-minute walk from such comforts. Each should be equipped with free drinking fountains. Such facilities should be designed to be compatible with the historic landscape and to meet LEED criteria and could feature: a green roof; renewable energy for 100 percent of needs; waterless toilets; non-toxic building materials; cisterns for rainwater harvesting; and 50 percent recycled content. These buildings in and of themselves should be exemplars of the principles of sustainability, as thousands of people will use them daily.
- Hard materials for landscape construction should be regionally produced and exhibit 50 percent recycled content. Any wood used should be certified as sustainably harvested. Pavements should be light-colored to minimize urban heat island gain while considering glare and the quality of experience for visitors.
- All waste from the Mall visitors should be sorted into different trash receptacles - paper, plastic, glass, metals, and organic - for easy recycling. All construction waste shall be sorted and recycled in a similar manner.
- A signage and education program for these sustainable practices should be incorporated into an overall wayfinding system that features both fixed, hard construction of sign panels but also electronic media available through cell phones and laptops over a free WiFi zone. This information should include programs and activities, as well as features and destinations, so that pedestrians are fully informed and unnecessary vehicular trips are eliminated.
- All temporary security barriers should be removed from the National Mall area, and should permanent security measures be necessary, these should be designed as a seamless, integral part of the context of the site and not restrict free and open pedestrian access. The perimeter security measures around the Washington Monument utilize low walls to maintain safe and open public spaces and exemplify the coexistence of good design and effective security.