text: Ideas for green urban structures began in the 1870s with concepts of urban farming and garden allotments. Alternative terminology includes stormwater best management practices, source controls, and low impact development (LID) practices.
  Green infrastructure concepts originated in mid-1980s proposals for best management practices that would achieve more holistic stormwater quantity management goals for runoff volume reduction, erosion prevention, and aquifer recharge. In 1987, amendments to the U.S. Clean Water Act introduced new provisions for management of diffuse pollutant sources from urban land uses, establishing the regulatory need for practices that unlike conventional drainage infrastructure managed runoff "at source." The U.S. Environmental Protection Agency (EPA) published its initial regulations for municipal separate storm sewer systems ("MS4") in 1990, requiring large MS4s to develop stormwater pollution prevention plans and implement "source control practices". EPAs 1993 handbook, Urban Runoff Pollution Prevention and Control Planning', identified best management practices to consider in such plans, including vegetative controls, filtration practices and infiltration practices (trenches, porous pavement). Regulations covering smaller municipalities were published in 1999. MS4s serve over 80% of the US population and provide drainage for 4% of the land area.
  Green infrastructure is a concept that highlights the importance of the natural environment in decisions about land-use planning. However, the term does not have a widely recognized definition. Also known as “blue-green infrastructure”, or “green-blue urban grids” the terms are used by many design-, conservation- and planning-related disciplines and commonly feature stormwater management, climate adaptation and multifunctional green space.
  The term "green infrastructure" is sometimes expanded to "multifunctional" green infrastructure. Multifunctionality in this context refers to the integration and interaction of different functions or activities on the same piece of land.
  The EPA extended the concept of “green infrastructure” to apply to the management of stormwater runoff at the local level through the use of natural systems, or engineered systems that mimic natural systems, to treat polluted runoff. This use of the term "green infrastructure" to refer to urban "green" best management practices contributes to the overall health of natural ecosystems, even though it is not central to the larger concept.
  However, it is apparent that the term “blue-green infrastructure” is applied in an urban context and places a greater emphasis on the management of stormwater as an integral part of creating a sustainable, multifunctional urban environment. At the building level, the term "blue-green architecture" is used, which implements the same principles on a smaller scale. The focus here is on building greening with water management from alternative water resources such as grey water and rainwater.