Recent chat on LinkedIn brought a new combined acronym to my attention - LID/GI.
The North American stormwater industry knows the acronym LID. Low Impact Development, or LID for short, is a land planning/engineering approach which uses small-scale, “natural” hydrologic controls (i.e., infiltration, filtration, evaporation, detention close to the source, storage/reuse,) to mimic pre-development hydrologic conditions. LID is an important tool for meeting the goals of the Clean Water Act and plays a role in Greening Cities, Smart Growth, and Green Infrastructure (GI).
In reference to the USEPA website, GI appears to be the integrated consideration for habitat/energy/community/water/air. Keeping things at the highest (graphical) level – I could assume LID would support water-specific GI… wherein GI would be used to achieve the equivalent paradigm shift that the Australians did with water-sensitive urban design (WSUD) in 2009…. to encourage management of stormwater runoff as a resource rather than a nuisance or liability. At least, this is where my heart hoped the conversation will/would lead.
Alas, the story forms a bit differently.
“Unlike single-purpose gray stormwater infrastructure, which uses pipes to dispose of rainwater, green infrastructure uses vegetation and soil to manage rainwater where it falls.” If interpreted strictly, this would exclude container-ized aspects of LID (tanks, barrels, cisterns), making GI a sub-set of LID. This language appears to be in closest parallel to the April 2007 Green Infrastructure Statement of Intent, wherein this natural approach to proposed for managing sanitary sewage overflows and/or combined stormwater/sanitary sewer overflows. Similarly, California’s January 2012 Green Design funding guidance, Guidelines for Green Infrastructure Components, references green roofs and porous pavement for infiltration and evapotranspiration.
However, the GI discussion on the USEPA website lead and supporting case studies for cisterns, bioinfiltration, porous concrete, stormwater vaults, drought tolerant landscaping, etc… making the case for GI and LID to be interchangeable – a single acronym – when considered in the stormwater world. Examples of this merging of terms is increasingly prevalent in USEPA documents, state permits, agency discussions, and even professional commentary.
So it appears that the potential for GI to push the envelope, to shift a paradigm, has slipped back into the same old story of stormwater management. LID/GI rules supreme, where liability tracking continues, water flows and capture/reuse remains the benefit++ target of the rare, brave, and few.
