Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Bibliography: leaves 108-110. / by Judith Joan Wagner. / M.C.P.

In the United States, an aging and overburdened urban infrastructure has become a substantial challenge for civil engineers. Among these challenges, systems for stormwater management are of significant concern, considering their direct impact on environmental quality, local ecosystems, and the hydrologic cycle. Given the high costs for rehabilitation of traditional stormwater infrastructure in urban settings, low impact, or "green" development strategies have become critical components in plans for meeting future stormwater management goals. In particular, New York City (NYC) has pledged $1.5 billion over the next 20 years to improve environmental quality through the mitigation of urban runoff, where utilization of green infrastructure is a primary goal. Cost effective implementation of this, and similar plans around the world, requires comprehensive understanding of green infrastructure functionality. In response, this dissertation investigates the stormwater management potential of full-scale green roofs in NYC through lenses of observation, modeling, and design. Exploration of this topic has resulted in new findings which quantify the: influence of dominant environmental and physical properties on green roof hydrologic performance, envelope of potential green roof rainfall capture in NYC, and predictive efficiency of contemporary hydrologic models for green roof assessment. This work has also lead to new methods for the: extension of green roof observations to account for the influence of rainfall distribution, parameterization of green roof hydrologic processes, and prediction of full-scale green roof rainfall capture in advance of construction. Going forward, these findings and methods are useful for informing green roof policy, planning, and design; where, in particular, this information supports the development of green roof policies that correlate to specific stormwater management goals. In summation, the characterization of green roof stormwater management in NYC, as presented in this dissertation, has contributed to the understanding of, among other topics, green roof design, urban stormwater management, hydrologic modeling, and the broad interdisciplinary field of urban ecological systems.

The conversion of natural landscapes for human use over the past century has led to significant ecological consequences. By clearing tropical forests, intensifying agriculture and expanding urban centers, human actions have transformed local, regional and global hydrology. Urban landscapes, designed and built atop impervious surfaces, inhibit the natural infiltration of rainfall into the subsurface. Deforestation, driven by the demand for natural resources and food production, alters river flow and regional climate. These land cover changes have manifested into a number of water management challenges, from the city to the watershed scale, and motivated investment into landscape re-greening programs. This movement has prompted the need for monitoring, evaluation and prediction of the hydrological benefits of re-greening. The research presented in this dissertation assesses the contribution of different re-greening strategies to water resources management, from multiple scales. Specifically, re-greening at the city scale is investigated through the study of vegetated rooftops (green roofs) in a dense urban environment. Re-greening at the watershed scale is investigated through the study of forest regeneration on deforested and ecologically degraded land in the tropics. First, the benefits of city re-greening for urban water management are investigated through monitoring and modeling the hydrological behavior of a number of green roofs in New York City (NYC). Influence of green roof size and rainfall characteristics on a green roof’s ability to retain/ detain rainwater are explored and the ability of a soil infiltration model to predict green roof hydrology is assessed. Findings from this work present insight regarding green roof design optimization, which has utility for scientific researchers, architects, and engineers. Next, a cost effective tool is developed that can be used to evaluate green roof hydrologic performance, citywide. This tool, termed the Soil Water Apportioning Method (SWAM), generates green roof runoff and evapotranspiration based on minimally measured parameters. SWAM is validated using measured runoff from three extensive green roofs in NYC. Additional to green roofs, there is potential for SWAM to be used in the hydrologic performance evaluation of other types of green infrastructure, making SWAM a relevant tool for city planners and agencies as well as for researchers from various disciplines of study. Finally, the impact of degraded landscape re-greening is investigated using a case study of 15 watersheds in Puerto Rico that have experienced extensive reforestation. The study provides evidence of improved soil conditions following reforestation, which in effect positively impacts streamflow generation processes. Findings from this work fill a gap in knowledge regarding the hydrological benefits of forest regeneration in mesoscale watersheds and provide guidance for future investment into reforestation programs. Land cover will inevitably continue to change to meet the needs of a growing and increasingly urban population. Yet there is potential to offset some of the ecological effects – especially those on hydrology – that result from land cover change. As a whole, this dissertation aims to contribute knowledge that can be used to make the re-greening of altered landscapes more realizable.

Urban stormwater runoff from impervious surfaces reduces water quality and ecological diversity in surrounding streams. The problem is exacerbated in older cities with combined sewer systems like New York City, where roughly 30 billion gallons of untreated sewage and stormwater runoff are combined and dumped into the New York harbor annually. Rain gardens and green roofs are designed to naturally manage stormwater, but both performance data and design guidance are limited. In particular, rain gardens are not optimized for nutrient removal, and US green roofs are commonly planted with non-native vegetation, which may not be optimized for water retention. The first of three studies in this dissertation investigates the overall effect of rain gardens on nutrient removal. Engineers have found there to be tradeoffs between rain garden designs that overall favor greater water retention and those that favor removal of pollutant nutrients, as efficient nutrient removal requires designs that drain slowly, and thus absorb less stormwater. Despite these opposing concerns, this dissertation has found that rain gardens constructed in areas with combined sewer systems should focus on water retention, as the benefits of treating increased amounts of water outweigh admitted downsides, such as the leaching of pollutant nutrients contained in rain garden soil. The second study investigates how nutrient pollution can be reduced in rain gardens. To do this, it quantifies the rate that the rain garden’s soil creates nitrogen pollution, by converting nitrogen from organic to inorganic forms, as inorganic nitrogen is more readily washed out of the soil and into water bodies. Conversely, it also quantifies the amount of nitrogen consumed by plants and also nitrogen emitted in gas form. It then uses the results to construct an overall nitrogen mass balance. The results indicate that the soil used to build rain gardens is in fact too nitrogen rich; inorganic nitrogen supplied by the decomposition of organic nitrogen and by stormwater runoff is far greater than required to maintain vegetative health for rain garden plants. The study concludes that altering rain garden soil specifications could reduce nitrogen pollution. The third study finds that “industry-standard” green roofs planted with drought-tolerant Sedum vegetation might not capture as much stormwater as “next-generation” native systems with irrigation and smart detention. Specifically, the study provides crop coefficients demonstrating reduced evapotranspiration in drought tolerant green roof plants compared to native plants. It also found a native roof’s stormwater capture increased with irrigation and the use of a smart runoff detention system, which automatically reduced the volume of water in the cistern that captures roof runoff in advance of a predicted storm. US government agencies are launching multi-billion dollar greening initiatives that include rain gardens and green roofs designed to manage volumes of stormwater runoff. The research here can assist in quantifying performance and improving green infrastructure designs.

As the numbers of installed greenroofs continue to grow internationally, designing greenroof growing media to reduce the amount of nutrients in the stormwater runoff is becoming essential. Biochar, a carbon-net-negative soil amendment, has been promoted for its ability to retain nutrients in soils and increase soil fertility. This study evaluated the effect on water quality of greenroof runoff after adding biochar to a typical extensive greenroof soil. Prototype greenroof trays with and without 7% biochar (by weight) were planted with sedum or ryegrass, with barren soil trays for controls. The greenroof trays were subjected to two sequential 2.9 in/hr rainfall events using a rainfall simulator. Runoff from the rainfall events was collected and evaluated for total nitrogen, total phosphorus, nitrate, phosphate, total organic carbon, and inorganic carbon. Greenroof trays containing biochar showed lower quantities of nutrients in the stormwater runoff compared to trays without biochar. Biochar-amended soil with and without plants showed a 3- to 25-fold decrease in release of nitrate and total nitrogen concentrations, as well as a decrease in phosphate and total phosphorus concentrations release into the rainfall runoff. Phosphorus results from trays planted with sedum indicate that sedum interacted with both soils to cause a decrease of phosphorus in the greenroof runoff. In correlation with a visual effect in turbidity, biochar-amended soil showed a reduction of total organic carbon in the runoff by a factor of 3 to 4 for all soil and plant trays. Inorganic carbon was similar for all tests showing that inorganic carbon neither reacted with, nor was retained by, biochar in the soil. The addition of biochar to greenroof soil is an effective way to retain nutrients in a greenroof soil, reduce future fertilizer demands, and improve the water quality of the stormwater runoff by reducing nitrogen, phosphorus, and total organic carbon concentrations in the runoff water.

Nonmarket activities such as gardening and cooking are often correlated with increased well-being and happiness. Additionally, nonmarket, casual activities such as gardening and food preparation are often internally motivated, and provide observable examples of self-concordant experiences. Self-concordance, i.e., internalized motivation, has been shown to increase satisfaction and increase efficacy of goal attainment. Further, experiential hobbies such as gardening may help individuals feel more satisfied, adopt more intrinsic life aspirations, and be less materialistic. This study explored satisfaction, materialism, and food activities by focusing on first-person, lived experiences of eight urban gardeners in Portland Oregon who grow, prepare, and eat their own food. Little is known about what specific food experiences lead to increased feelings of well-being and satisfaction. Whereas previous research focused on defining and assessing materialism based on life aspiration measures, this study explored how intrinsic life aspirations translate into concrete, lived experiences expressed through food activities. The goal of the current study was to gain a deeper understanding of how food experiences satisfied the psychological needs of urban gardeners. Qualitative analysis of interviews and other data revealed that food experiences: 1) were motivated by intrinsic reasons, such as competency, creativity, and curiosity, and also sometimes for extrinsic reasons such as status and security, 2) were affected by enabling factors such as social relationships, and disabling factors such as time, energy, and financial limitations, and 3) resulted in increased life satisfaction, and feelings of strength, and confidence. Additionally, participants' level of general materialism often corresponded with their level of materialism regarding their food experiences. The results indicated that individually tailored experiential long-term food related hobbies are highly valued and a source of great satisfaction for a variety of psychological needs, such as relatedness, connection, work-life balance, and abundance. These results show that food activities can be intrinsically satisfying and can mitigate the negative effects of materialism. The findings from this study build theory and provide direction for potential future research in reducing materialism by developing measures for types of satisfaction from food activities and testing correlations with materialism and life satisfaction.

Over fifty percent of humans live in cities. The environmental cost of this is massive, as is the potential for utilizing privately held yards as an integral part of conservation in urban areas. The Backyard Habitat Certification Program (BHCP) in Portland, Oregon, was established to reduce invasive plants, support wildlife, and promote conservation. The program involves > 3000 yards certified at three tiers. While onsite inspections are required to verify compliance, there has never been an assessment of the value of these yards to wildlife. Chapter 1 examined the relationships between the urban landscape and bird distributions outside of yards. Chapter 2 evaluated the ability of the program to separate yards by assessing differences in vegetation structure and composition. Chapter 3 tested if avian abundance, richness and diversity in yards are a product of responses to yard or landscape vegetation structure. Avian data was collected at 146 yards and 73 random locations in 2013 and 2014. Public landscape data was used to collect yard data in the field. Avian abundance, richness, and diversity were affected negatively by urbanization (especially impervious surface) and population density, but positively by tree cover. The BHCP was effective at distinguishing platinum yards from others, but overlap was relatively high among gold, silver and uncertified yards. Avian abundance, richness and diversity within yards was less affected by yard vegetation than the structure of habitat in the surrounding landscape. Species responded individualistically to yard vegetation and the urban landscape, and response was a continuum of tolerance to urbanization. Ultimately, the ability of yards to support wildlife will depend on wide scale neighborhood participation.

Ozone in indoor environments can pose a health risk to human occupants; around half of exposure to this pollutant occurs inside buildings. One approach to reducing indoor O3 levels is to mitigate O3 as it enters a building via outdoor air ventilation supply. Often, mechanical systems that introduce outdoor air into buildings are placed on building rooftops. At the urban scale, greenery has been shown to reduce levels of some harmful pollutants, including ozone and cities like Portland, OR, are mandating green roofs be built on large commercial buildings to increase urban green surfaces. We investigate if rooftop vegetation may act as a sink for O3 as transport occurs across a green roof. It is known that O3 can react with vegetated surfaces and the ground but there is scant empirical research on said pollutant dynamics on vegetated green roofs, and little data concerning pollutant interactions occurring on other rooftop designs. Essentially unstudied is the potential of rooftop designs to affect local concentrations of pollutants where building outdoor air supply may be co-located. In this study, we investigate O3 dry deposition using resistance uptake theory in an area that includes a green roof on a local big box retail store through a field study conducted during a two-week period in the Summer of 2017. Deposition velocities and subsequently surface resistances were measured. The 10th, 50th, and 90th percentiles for resistances were 54.8 s/m, 195.3 s/m, and 3692.9 s/m respectively. A 2-D advection-diffusion model of rooftop deposition is employed to describe transport across the green roof and sensitivity analysis was performed to compare the impact of different parameters. The sensitivity analysis demonstrated that the fetch length and the vegetation height had the biggest impact, followed by the meteorological parameters; the friction velocity and heat flux. The surface resistance had the least impact on deposition. An ideal case was used to demonstrate that even when conditions are maximized for deposition, the impact on the concentration gradient is minimal at best.

Through the implementation of a garden project in two women-centred correctional facilities in New South Wales, this thesis explores tensions between punitive and rehabilitative goals. The impacts of these tensions on the garden project and the every-day lived experience for female inmates form the basis of the research. Initially, the research looked at the rehabilitative potential of a horticultural therapy program for female inmates. This focus correlated with the holistic rehabilitative rhetoric within women’s prisons in New South Wales. Based on this, a small garden project of five months’ duration was conducted in each of the two correctional facilities over a twelve month period in 2006. Through the implementation and evaluation of this research conflicts between hierarchical, dominating systems of the penal institution and holistic, rehabilitation goals of the garden project were exposed. Utilising qualitative data analysis embedded in critical ethnography, the garden project provided a ‘key-hole’ view of these conflicts within the penal environment. The collective data from open- journaling was abstracted from raw data level through to theoretical constructs in combination with a further literature research. Foucault’s penal justice critique, Weber’s domination and Goffman’s totalitarian discourses informed the development of deeper understandings that enlightened on-going explorations in the field. As a result, theoretical understandings identified a tension within the penal environment that appeared to neutralise, fragment and corrode the intended benefits for female inmates of the garden project. This tension was identified as an intangible force, or penal phantom, representing the effects of totalisation within the penal environment. Two streams of inquiry emerged exploring the effects of the total institution on how power is exercised over female inmates and the implications upon the holistic, rehabilitative aims of the garden project. Findings from this research highlight the effects of the penal phantom upon female inmates’ lived experiences, the working realities for prison staff and how these impact upon rehabilitative programs for women in prison. The thesis concludes by examining these effects in the continued marginalisation of the current female inmate population and recommends a review of incarcerative practices that continue to entangle women within criminal justice systems. / Doctor of Philosophy (PhD)

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on December 6, 2007) Vita. Includes bibliographical references.