What is EPA Green Infrastructure?

Climate change can affect groundwater recharge rates and groundwater table elevation (Bates et al., 2008). With a worldwide anticipated increase in the urban population from 55% to 68% by 2050, and the impact of climate change, a sustainable solution to flood management is essential for the socio-economic growth of nations. In recent years, there has been a growing trend towards adoption of low-impact development practices managing stormwater runoff. These practices aim to mitigate the impacts of urbanization such as increased runoff volume, higher peak runoff flows, lowered water tables and reduced water quality (Prince George's County 1999). In contrast to conventional stormwater infrastructure, which is designed to rapidly collect and convey runoff, low-impact development practices are designed to slow runoff, remove pollutants and evapotranspiration and infiltrate runoff locally.

The U.S. Environmental Protection Agency (EPA) regulates under the authority of the Clean Water Act. In 2004, the EPA issued a report to Congress on the widespread nature of combined sewer overflows, citing 746 communities in the US that use combined sewer systems. The literal greening of the urban environment with vegetation (in the form of green infrastructure) provides opportunities for both reducing urban runoff volume and improving its quality. In a symposium in 2007, the EPA publishes a Memorandum that it presents a definition as "EPA Green Infrastructure", and states that green stormwater infrastructure as approaches that infiltrate, evapotranspiration, or reuse water as opposed to traditional hardscape conveyance (gray) infrastructure. Expanding on the definition, green infrastructure is a stormwater infrastructure that utilizes natural processes such as infiltration to decrease, slow down, and clean runoff (e.g., green roofs, bioswales, rain gardens, and permeable pavement).

During these years, EPA center has published several papers and reports that reveal "EPA Green Infrastructure" concepts and statements. All of them are really wonderful as the main sources that researchers can find their answers of questions, and also find and explore the new related concepts, regards to "EPA Green Infrastructure".

Life cycle assessment has been effectively applied to assess the environmental performance of water infrastructure including the environmental impacts associated with the construction, maintenance, and disposal of various green infrastructure technologies and the incremental life cycle impacts and benefits of adding green infrastructure on an existing stormwater management system for a variety of environmental measures. Green infrastructure solutions can be applied on different scales, from the house or building level, to the broader landscape level. Green infrastructure investments boost the economy, enhance community health and safety, and provide recreation, wildlife, and other benefits.

Green infrastructure mimics the natural hydrologic cycle by allowing infiltration of water at the source, providing for the slow return of water through soils to the groundwater, and allowing plants to absorb excess water and release it back into the atmosphere through evapotranspiration (Demuzere et al., 2014). Green infrastructure leverages ecosystem functions such as soil infiltration and plant evapotranspiration to reduce or slow the stormwater entering the sewer system (Dunn, 2010; DEP, 2010). The Green infrastructure approaches require a better understanding of hydrologic processes and urban land use factors in order to achieve more sustainable catchment management and planning. With changes in the approach to stormwater management, new methods and technologies are being employed to design infrastructure.

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