The Projected Impact of a Neighborhood-scaled Green Infrastructure Retrofit

Climate change and its related factors are increasing the frequency of hurricanes, coastal storms, and urban flooding. Recovery from disasters can be slow, with jurisdictions failing to build back better, wasting time and money without improving resilience to the next disaster. To help attenuate floods and mitigate their impacts, Low Impact Development (LID) and the incorporation of green infrastructure (GI) is gaining in popularity. LID installs more natural methods of absorbing, redirecting, retaining, and filtering water, through GI installations such as rain gardens, detention ponds, and the reduction of impervious surfaces. LID is, however, primarily implemented and evaluated only on a local scale; few studies have assessed the broader impacts of GI on a larger scale. In fact, most performance calculators that evaluate the effects of GI are only useful at the site scale. Further, most advocates of GI propose its use in new developments, without much attention to retrofitting existing, suburban development. This article seeks to determine what the potential effects of retrofitting an existing, suburban neighborhood with GI for flood protection at a larger scale could be, using Sugar Land, Texas, USA as a case site. First, low-impact facilities are proposed and schematically designed at a site scale for a typical single-family lot. The volume of rainfall that can be retained on site, due to each incorporated feature, is then derived using the Green Values National Storm Water Management Calculator. Using this data, the total volume of rainfall that could be retained if all residential sites in Sugar Land incorporate similar facilities is then projected. The result show that Sugar Land has the capacity to capture 56 billion liters of stormwater water annually if all residential properties use LID. Additional benefits of the use of GI include reduced heat (37%), improved aesthetics and property values (20%), increased recreational opportunities (18%), improved water quality (12%), improved air quality (5%), increased green collar jobs (4%), reduced damage from harmful gas emissions (3%), and increased energy savings (1%), thereby surpassing conventional storm water management techniques [1].