The majority of urban hydrological models focus primarily on differences in the rainfall-runoff ratio between pervious and impervious area. Impervious area (as I have mentioned in a previous post), is traditionally assumed to be the major causal source of changes in the hydrological cycle associated with urbanization. Infrastructure-centric urban hydrologic models assume that water that is infiltrated or evapotranspirated before reaching drains and pipes has “exited” the system. As more and more infiltration-based stormwater control measures are implemented however, this assumption needs to be more closely examined. Are urban soils and the urban subsurface truly effectively inexhaustible in capacity? This question is particularly important when we think about multiday rain events and changes in intensity of rainfall associated with climate change.
For the past twenty years, the understanding that impervious surface cover as the main causal factor for the ‘flashier’ runoff response of urbanized watersheds, has been the major focus of integrated water-land planning. Such a view however, ignores other processes by which flashy runoff response may be induced through urbanization. Better understanding of specific runoff production processes and broader views of green infrastructure planning are needed.
Systems that include budgets for GI come disproportionately from the top 20% of systems, by reported CSO correction need.
One key to more widespread adoption instead should be to promote citizen buy-in to the other benefits of green infrastructure: beautification, subsidized landscaping upgrades, and appeals to individuals’ social pressure to “do the right thing.” The goal should be to promote the idea that “everyone is doing it.” Social media could be a great way of getting people to talk about the availability of stormwater management programs and making them more visible.
The article “Akron files federal motion to reopen agreement addressing overflowing sewers” caught my attention this morning. Requests to amend or change existing consent decrees filed with the EPA are not unheard of, especially in cities who adopted their Long Term Control Plans relatively early, after the 1994 CSO Control Policy was passed, which required all cities with combined sewer systems to put together plans to characterize and reduce and sewer overflows due to wet weather events. In this article however, the author states that Akron’s effort for an Integrated Plan incorporating more green infrastructure components has been twice rejected by the EPA.
On Jan 8th, I attended a one-day workshop organized by the nonprofit NJ Future, the NJ DEP and the US EPA in Newark, NJ called “Reinvesting in Urban Water Infrastructure through Combined Sewer Overflow Long Term Control Plans.” Contrary to how technical and engineering-heavy as the name of the workshop might seem to imply, the experience highlighted a major trend in infrastructure planning, function, and operation and management: decentralization. Gone are the days of the heroic engineer-city planners, yielding the Promethean control of nature, and as a result, over other people. This workshop was a representative of the parties that need to be involved in the research, reinvestment, and implementation of water infrastructure upgrades all over the United States.
New Jersey is at a very special crossroads with respect to its response to the EPA’s National Combined Sewer Overflow Strategy (1987) and the CSO Control Policy (1994). While larger cities such as New York City and Washington DC are well underway, New Jersey’s Department of Environmental Protection is in the midst of issuing new permits for the 21 communities in NJ with combined sewer overflows. This is an exciting time for NJ, because despite being somewhat behind other cities in the implementation of the CSO Control Policy, it has the opportunity to utilize the lessons learned from other communities’ implementation, and to do so in a proactive, collaborative way.
It’s undoubtedly a buzzword of sustainable development, but what does it really refer to? I’ve identified two main “schools” of green infrastructure thought: the city-centric school and the natural resource-centric school. These two schools focus on different, yet complementary aspects of sustainable development. In the former, green infrastructure refers to the action of “greening” existing infrastructure that serves cities. The emphasis is on city resource, material, energy, and even economic flows. In the latter school, green infrastructure refers to the the action of “infrastructuring” greenness, or the systematization and rationalization of natural and working open space planning. Here, the emphasis is on acknowledgment and protection of ecological services and natural resources that support humans from outside urban areas.
A few events– specifically the Legacy and Innovation forum at UPenn back in October, and a session I attended during Greenbuild last week called “Innovative Governance for One–Water: Research and Action Plan”– have been solidifying the idea for me that legacy includes much more than aging physical structures. Perhaps even more challenging are the regulatory and institutional frameworks developed to complement the physical networks.
The plight of Detroit, which has been prominently covered both in the media and in urban planning circles, may be an extreme example of urban decay, with its reported (albeit now falling) 25% vacancy rate and startlingly eerie images, but it is hardly a unique phenomenon. Legacy cities, those once prosperous centers of industry and culture are now struggling to survive in a new knowledge-based economy. So what does green infrastructure have to do with this conversation? It’s all about a changing concept of resiliency.