.|  Baltimore Ecosystem Study
HERCULES Feedbacks
Feedbacks between Complex Ecological and Social Models: Urban Landscape Structure, Nitrogen Flux, Vegetation Management and Adoption of Design Scenarios
The Urban Design Working Groug (UDWG) has been modeling urban design scenarios for three neighborhoods in the Baltimore region as part of a Biocomplexity research grant on coupled human and natural systems. The research team, consisting of Steward Pickett , Larry Band, Mary Cadenasso, Morgan Grove, Brian McGrath, Mary Washington, Don Dennis, Peter. Groffman, and Austin Troy, worked with the urban-interface team of Mateo Pinto, Jacinto Padin Obina and Victoria Marshall. Figure 1 illustrates the feedback loop tying together the ecological, hydrological, social science and design researchers in the project superimposed over a topographical map of Gwynns Falls. Three neighborhoods were selected by the team in order to understand the interactions of nitrogen flux with landscape structure and management with proposals for design scenarios which introduced new water and vegetation management options based on neighborhood preferences; Baisman Run and Dead Run in Baltimore County and Harlem Park in Baltimore City. Figure 2 locates the three neighborhoods on a key map and illustrates the different building densities in relation to block morphology and direction of stream (buried or surface) flow.

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A detailed photographic survey by McGrath and Pinto (Figure 3) compares the relationship between house, yard and street in the three neighborhoods. Using Bing on-line aerial photography, the team identified three scales of intervention to work at which operate within three realms of social organization: individual property parcel, shared backyard space, and the municipal infrastructure of streets and parks (Figure 4). From that a matrix of existing problems and best management options was created (Figure 5).

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Baisman Run (Figure 6 and 7) is a 381 hectacre watershed which is 80% forested, but contains unsewered residential land use in the headwaters (BES Core Data, 2009). Springfield Farm Court is a s-shaped meandering road which winds down from Falls Road over two hillocks to a cul-de-sac at the edge of Oregon Ridge Park. The Park encompasses a forested tributary stream leading to Jones Falls, flowing parallel to Interstate 83 to downtown Baltimore before emptying into the Inner Harbor. Large houses on four acre lots line Springfield Farm Court, and several small tributary streams are preserved through riparian setback regulations. However, upon closer inspection, the streams are incised deeply into the soil and are not producing the mucky, slow pools filled with organic litter which provide so many ecosystem services in a forested headwater area. The wide street and large residential driveways rush rainwater to catch basins which feed directly into flashy, fast moving streams. The system cannot retain the nitrogen exported by the residential septic systems (Cadenasso et. al, 2008, Pickett et. al, 2007).

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Dead Run (Figure 8 and 9) is a tributary to the Gwynns Falls -- a watershed parallel to the Jones Falls. Much closer to the center city, Dead Run consists of much denser and older suburbs of ranch houses on small lots on curving blocks with neighborhood parks. Gilston Park Road is a typical street in the neighborhood, and it winds down steeply, then flattens as it curves down to Westview Recreation Area where a stream is exposed in a small forested area adjacent to recreation fields. In the residential blocks of Dead Run, the streams are buried, and only exposed in the parks. But unlike Baisman Run, here there is a sanitary infrastructure separate from the storm water system. American suburbs built before Clean Water Act of 1972 regulations took effect consistently buried streams, but often created neighborhood parks. In these older suburbs close to the city line, Elmore and Kaushal find more than 50% of the historical headwater streams have been buried . (Elmore, Andrew J. and Sujay S. Kaushal, 2008, Disappearing headwaters: patterns of stream burial due to urbanization", Frontiers in Ecology 6(6): 308-312).

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In the West Baltimore neighborhood of Harlem Park, (Figure 10 - 14) the percentage of stream burial is 100%, and the vast majority of rain water is channeled directly into the Bay. This area is part of storm water subcatchment called Watershed 263, which, like Gwynns Falls, empties into the Middle Branch. Both the Middle Branch and Inner Harbor empty into the Patapsco River, and eventually Chesapeake Bay. The Harlem Park neighborhood is named for the 19th century residential square at its heart. Additionally, As part of the Model Cities Program, in 1966, a series of midblock parks were constructed in place of demolished alley housing. Here open space consists of playgrounds, residential squares, and vacant lots are the only open spaces in which to incorporate open water streams. It is only through new community greening efforts creating rain gardens in vacant lots and school parking lots, retention tanks in new construction, and proposals for historical stream day-lighting and green roofs that offer the possibility of returning this area to a water and nitrogen retention zone. Students at Columbia University's Urban Design Program worked in collaboration with the BES over many years to propose multiple ways to create a spongy absorbent environment for this and other neighborhoods in West Baltimore. (Brian McGrath,V. Marsahll, M. L. Cadenasso, J. Morgna Grove, S.T.A. Pickett, Richard Plunz and Joel Towers, 2007, Designing Patch Dynamics, New York : Graduate School of Architecture, Planning and Preservation of Columbia University.)

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