Experts in green infrastructure provided essential vetting of ideas for feasibility regarding costs and engineering considerations. The two following experts are featured here because they provided at-length feedback that helped the Terrascope Class of 2024 proposal address the “bigger picture” of biodiversity by integrating content from the myriad resources consulted over the course of the research.
One pioneer in the field of green infrastructure is Dr. Heidi Nepf at MIT. Dr. Nepf focuses her study on fluid mechanics as it pertains to ecological engineering, and she provided insight on how to improve Terrascope Class of 2024 stormwater management proposals. First, she shed light on the unique advantages of existing green infrastructure solutions to inform Terrascope Class of 2024 proposals for placement of solutions within a city. Bioswales, for example, are quite versatile while being effective in absorbing and conducting stormwater into cisterns or other underground storage spaces. They accomplish all this, yet they do not require much land, do not demand a great height gradient, and can be implemented with plants or even large rocks, as found behind the Stata Center at MIT.
Another theme that emerged from the discussion was that flexibility in the solution proposal is key. The more options for green infrastructure that a city entertains, the more likely it is to eliminate stormwater runoff due to the combination of solutions. In addition to bioswales, another distinct solution is the detention pond, more capable of managing fast-moving stormwater in the event of a flood. The benefit of this collection feature is that it delays movement of water so that filtering and flood prevention are realized. The water is also not stagnant, which lowers the risk of creating certain public health issues related to standing water in a heavily populated area. Such a pond can even be reimagined to less resemble a man-made structure and more a natural wetland so that wildlife may find more habitat while the city gains an effective flood control solution. These different methods depend on many factors like topography and surface area available, but having many options is in fact ideal. According to Dr. Nepf, “biodiversity needs a diversity of solutions to be successful,” and the redundancy of different methods that share the same purpose can increase the chance of success.
One more approach gleaned from the interview was the value of taking a historical perspective when finding solutions. It is expected that most new proposals rely heavily on existing foundations, but making the active effort to consider the roots of solutions can provide direction in how to extend and expand those initial ideas. The detention ponds, for example, started in suburbia in the 50’s and 60’s and have evolved to fit the needs of urban landscapes since then. Rain gardens have also traditionally been constructed in primarily residential areas, with individuals electing to build them as a way to control rainwater on their properties. Progressing the idea behind these structures to promote greater stormwater management in a city can better complement the needs of biodiversity in urban areas. This line of thought led to consideration of past efforts for creating contiguous green space in cities which allows for continuous habitats that support species beyond highly mobile birds and insects. A notable example is the Emerald Necklace of Boston, a connection of parks designed by Fredrick Olmsted in the late 19th century. Resurrecting old ideas meant to create public amenities for enjoyment of nature can reconcile two modern-day perspectives: those of landscape architects, who prefer curated spaces for humans, and those of ecologists, who advocate for greater conservation of nature for the sake of biodiversity.
To address the urban planning aspect of adaptive landscaping, MIT researcher Dr. Alan Berger, whose work includes integrating “devalued landscapes” back into productive areas of a city, was also consulted. He provided insight on how small-scale solutions such as rain gardens and bioswales can indeed be legitimate solutions for recovering as much biodiversity as possible in pavement-laden cities, supporting Terrascope Class of 2024’s proposal of introducing more projects suitable to confined spaces in a city center. The lack of surface area for terrestrial and aquatic life severely limits large-scale solutions, but his 1% rule presents a way to maximize the potential of “disvalued landscapes,” no matter how small. The concept is that an accumulation of smaller, perhaps seemingly insignificant, pockets of vegetation collectively reclaim land within cities so that a greater permeable surface area exists to prevent extensive stormwater runoff and sewer system overflow.
Dr. Berger also introduced the work of Peter Del Tredici, which claims that native plants cannot be expected to grow in nonnative soil. Therefore, the idea of using invasive plant species for preventing stormwater runoff should not be ruled out; in many cases, these are the only types of plants that can grow in contaminated soil. These plants in fact ensure that toxic water does not reach the waterways surrounding a city to cause algal blooms and decreased biodiversity.
In addition to inspiring new lines of research, these meetings aided Terrascope Class of 2024 in reframing the solution according to challenged assumptions. An example of this was accepting the value of certain invasive plants for the purpose of toxin removal, a decision whose benefits may outweigh its potential threats to biodiversity. Dr. Nepf’s point about considering the long-term tradeoffs of this very solution for toxin removal, however, was also valuable. The influence of these insights can be seen in the solution proposal here.