September 6, 2014
Joseph Cherichello, PLA
In this post-industrial age many opportunities present themselves to convert urban brownfields into open green spaces. Liberty State Park, a complex brownfield site in New Jersey, provides a case study of the crucial integration of ecology and design to redevelop the site and reintroduce public access.
Many sites developed for human use have relied on mechanical techniques to redirect and manipulate physical and biological processes for the benefit of fitting structures such as buildings and parking lots into the landscape. Water has been collected from impervious surfaces, forced into pipes (increasing rate of flow), and released into nearby streams (increasing temperature and volume compared to pre-development). However, if the environmental structure is overpowered, the impacts can be damaging – an increase of downstream flooding frequency and volume, and an increase in temperature and nutrient levels within the stream, can negatively affect wildlife and human activity in a number of ways.
Located on the west bank of Upper New York Bay, along with the Statue of Liberty and Ellis Island, Liberty State Park was an intertidal mud flat and salt marsh before it was developed by the Central Rail Road of New Jersey beginning in the 1860s (NJ Division of Parks and Forestry 2001). As New York became more industrialized and immigration increased dramatically, people began to view the natural resources in terms of technology and transportation (NJ Division of Parks and Forestry 2001).
The construction of the rail yard required the existing salt marsh to be filled with materials from various places, most of which came from construction projects in Manhattan and refuse from the surrounding areas. By 1967, use of the rail yard was discontinued and removal of infrastructure within the park began (NJ Division of Parks and Forestry 2001). Site features such as the Terminal Building, which has been refurbished and currently in use, and the attached rail shed are reminders of the site’s rich history.
Since the rail yard was abandoned, the interior section of Liberty State Park was left, and continues to be unused. Fenced off from the public because of soil contamination, plant communities tolerant of the soil conditions began to regenerate and have grown for the last 40+ years (NJ Division of Parks and Forestry 2001).
The main goal of restoring Liberty State Park is to provide the public safe access to the Park’s interior section through a trail system offering educational and passive recreational opportunities while maintaining the site’s existing plant communities and ecological functions. In a brownfield project such as this, the initial challenge is to provide the public as much access to nature as possible while protecting their safety.
One redevelopment option is to clear the entire area of all vegetation and cover the contaminated soil with fill material that is considered ‘clean’. Although this would provide an open expanse ready for almost any type of development, it would also eliminate many educational opportunities as well as any habitat for wildlife that has taken refuge in this environment.
The option developed in the Master Plan (prepared by Wallace, Roberts & Todd) is to leave the existing vegetation and soil in their current state and provide limited public access with environmental education opportunities through a trail system.
The ‘Hydrologic Trail’, which leads to the proposed constructed wetlands is the focus of the project’s trail system. Three nodes located along the hydrologic trail (with information and educational opportunities) demonstrates the blending of ecological principles with the art of designing an engaging experience through a series of successional plant assemblages.
Node 1 – The Trailhead
‘The Trailhead’ provides a shaded gathering space surrounded by a bioretention swale to collect stormwater runoff. It will not only provide information about the trails and history of the site, but it will also demonstrate the process of capturing rainwater in a bioretention swale to allow for infiltration back into the soil. This important stormwater management technique is a useful ecological design principle particularly in the urban environment to help filter the rainwater, recharge aquifers, and prevent flooding.
Node 2 – Succession and Space
‘Succession and Space’ engages the visitor by displaying the spatial significance of emerging from a forested area to an open meadow through various sub-nodes. The intent of this design sequence is to give the visitor a varying sense of space that is created by the construction of varying sized viewing platforms.
Node 3 – The Crossroads
‘The Crossroads’ is the convergence of many trails with information and views of nearby constructed wetlands. Future phases will include a ‘wetland and rail trails’ which will intersect the hydrologic trail at the crossroads. A bioretention basin will be constructed for the study of the success of various plant species used in rain gardens or to study plants that may help in the collection of particulate matter from stormwater runoff. An elevated landform will also be constructed to compare the effects of the typically hot and dry southern aspect versus more shaded and moist northern aspects on native plant species. Lastly, an area will be dedicated to conventional rectilinear experimentation plots to continue the research being conducted on site.
There are many dimensions to creating a successful project which combines both science and design. A Landscape Architect’s role in any design, including a restoration project such as this, starts with sufficient site analysis and the design of usable space and ecosystem services. The goal is to provide stimulating experiences for visitors throughout the landscape while maintaining the integrity and increasing ecological function. Determining the project site’s climate and microclimate, understanding its unique hydrologic functions and its relationship to the watershed, researching its specific soil properties and understanding the ecological dynamics between vegetation and wildlife are the first steps in the ecological design of any land development.
Similar to Great Ecology’s brownfield restoration projects, Liberty State Park demonstrates the benefit of thinking creatively about what otherwise may be considered a blight to the community and repurposing it to conserve or enhance the ecosystem services on site. It shows the complexity involved in the preparation and incorporation of a comprehensive site analysis to ensure the desired outcome with regards to the design of space and ecology.
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