Dawn Henning

Research Presentation

Dawn Henning

Dawn Henning
Methods of mitigating stormwater runoff through decentralized green infrastructure projects challenge existing systems of governance and present opportunities to engage new stakeholders including millions of private property owners

2014 Urban Fellow

Research Topic: Water Resources

Faculty Advisor: Gaboury Benoit

Social Dynamics of Stormwater Management: Private Lands in the Alley Creek Watershed

Urban Ecology seeks to understand the interactions between biophysical and social processes in human-dominated systems1. Watershed boundaries serve as a compelling tool through which to study urban ecology as the biophysical properties of a watershed are highly intertwined with human activity and social systems2. The way land is developed and used has a direct impact on the quality of the receiving waterbody. Urban watersheds are characterized by high levels of development in the form of roads, buildings, and parking lots that support and impact quality of life. These features create large percentages of impervious surfaces that impede the infiltration of stormwater during rain events and alter the natural hydrology of the watershed. Mitigating the impact of runoff from this development is crucial to improving the health of local rivers and creeks and their ability to support wildlife and recreational opportunities for residents and visitors. The urban landscape is dynamic and constantly evolving with the destruction of old buildings, development of new buildings, creation and loss of parkland, restoration of ecosystems, and the upgrade and maintenance of supporting infrastructure. In addition, there is a flux of people moving across the watershed boundary changing demographic and economic characteristics. Watershed management involves working within this dynamic physical and social landscape to encourage stakeholders (e.g. landowners, government agencies, planning and zoning commissions) to implement actions that support goals to improve the receiving waterbody. Depending on the size and density of a watershed, this could involve the cooperation and coordination of anywhere from hundreds to millions of individuals. In addition, or perhaps as a result, the traditional role of engineers and city agencies has been to provide solutions in the form of design, construction, and maintenance of centralized hard infrastructure located on public lands and in the public right of way. This “invisible” infrastructure is often undervalued by the public as it is out of sight, reliable, and requires no specific knowledge for its use. Over the last decade or so, a paradigm shift towards treating stormwater as a resource as opposed to a waste product has shifted solutions from expanding treatment plants and large storage tanks to include smaller, decentralized projects that capture and use stormwater at the source. Green infrastructure (GI), or the use of distributed, vegetated systems to capture stormwater runoff, has thus evolved as a competing solution to managing urban runoff.

In 2012, the New York City Department of Environmental Protection (DEP) formally included GI as part of its consent order with the EPA for mitigating combined sewer overflows. In addition to grey infrastructure improvements, a goal was set to manage stormwater from 10 percent of the impervious surfaces in NYC using green infrastructure by 2030.3 While the DEP expects to fulfill the obligations of the Consent Order largely by installing GI on public property, in most watersheds, this goal cannot be met by capture on public property alone and will involve some capture on private lands. Best practices for engaging with homeowners in urban watersheds have yet to be developed. Decentralized GI projects present new opportunities to engage actors that previously did not concern themselves with stormwater infrastructure. This paper will use the Alley Creek watershed in Queens, NY as a case study to examine community perceptions of private property for watershed planning. In the Alley Creek watershed, 62 percent of the land area is zoned as residential which indicates that homeowners have a particularly strong influence over the landscape of the watershed. Therefore, understanding how homeowners perceive their private property, what factors drive their maintenance practices, and what prevents implementation of stormwater management measures can assist decision-makers in developing appropriate programs, incentives, and regulations to achieve better land use practices on residential property. The specific objectives of this research are to 1) define and characterize social-site typologies of private homeowners, 2) design effective methods of outreach and engagement for each of these typologies and 3) offer management recommendations moving forward. By breaking homeowners and their landscapes into distinct typologies, we can begin to address individual homeowners in groups and develop appropriate methods of outreach, engagement, regulation and incentives accordingly.

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