Shrinking Cities

Green Infrastructure

Infrastructure is the collection of systems that make communities function. Infrastructure commonly includes roads and highways; electrical grids; and systems that transport potable water, grey water, sewage and storm water. Traditional infrastructure is defined by its dependence on systems designed and constructed by people.

Green infrastructure attempts to replace engineered systems with systems that mimic natural processes. Systems can be created at many different scales, and many systems can be purchased for the individual home. Low impact development promotes green infrastructure for water management -- either to retain and reuse storm water and grey water, or to clean water using plant and soil systems. Alternative energy projects create electricity without carbon emissions using wind, wave or solar power; or use biogas from landfills and other sources to replace fossil fuels. Additionally, alternative energy projects can overcome built-in inefficiencies of centralized distribution and long transmission distances common to large-scale coal or nuclear plants.

Right aligned image, portrait orientation, 150 by 200 pixels

Image Caption

Green infrastructure concepts have expanded our ideas of what infrastructure can be. Advances in our ability to calculate the impact of trees on urban heat island affect and carbon sequestration have lead to considering urban forests green infrastructure. Bike lanes on roadways, signed trails, bikes sharing programs and bike rack installation are considered “bike infrastructure.” Urban agriculture on large and small scales, when linked to networks of farmer’s markets, is “food infrastructure.” This network secures the nutritional needs of the community and reduces its dependence on transportation and biomedical infrastructures employed by large agri-businesses.

The conditions of shrinking cities pose interesting questions for people concerned about infrastructure. Municipalities may see large vacancies as an opportunity to replace engineered systems with green infrastructures that have lower maintenance costs and negative impacts. However, green infrastructure is not a panacea. Natural areas provide their environmental services on their own terms, changing and evolving in response to surrounding conditions. A green infrastructure system’s usefulness depends on maintaining consistent or increasing levels of environmental performance, requiring human stewardship.

Despite these challenges, green infrastructure remains an attractive set of solutions for shrinking cities. Taking unused land and repurposing it in ways that reduce pollution, replace expensive grey infrastructure systems, increase habitat and promote human health is a net positive, especially since systems and projects can often serve multiple functions at the same time.