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Green infrastructure is a system of green spaces that conserve the values and functions of the natural ecosystem and provide associated benefits to humans. Green infrastructure used as a stormwater treatment mechanism is applied mostly at the local level through the use of natural or engineered systems to cleanse water and reduce excess volumes by filtering and treating it using plants, soils, and microbes. Rather than the traditional grey hardscape collection, conveyance and storage structures are used to treat pollutant loaded run-off. Some common green approaches are green roofs, rain gardens [PDF], vegetated swales, planter boxes, permeable pavement, bioretention, and pocket wetlands, in addition to rain barrels [PDF] and cisterns to capture and re-use stormwater.
Indiana is actively taking Green infrastructure approaches in communities, municipalities and industry in order to soften the impacts of contamination on water resources. While communities are developing and expanding, the need to preserve natural vegetation and reduce impervious surfaces for pollution management is vital. Green infrastructure, smart growth, and low impact development are all concepts that are referenced in Indiana's regulations and are promoted as an option for storm water management. Porter County has been progressive in implementing Green infrastructure approaches. The Porter County Jail has a large bioretention area and rain garden to slow the flow of stormwater-runoff discharging to the storm sewer system. The City of West Lafayette has been proactive in installing permeable pavement on and around the Purdue University campus. IDEM has also been in discussion with INDOT on a rest area where they are planning to construct a multi-stage wetland area and several bio-retention areas.
Green infrastructure practices can be both fiscally and environmentally beneficial to Indiana communities by reducing project costs and improving environmental performance. The American Recovery and Reinvestment Act of 2009 provided $6 billion in federal dollars to states for high priority infrastructure projects with the understanding that 20% of these funds would go toward Green infrastructure and energy and water efficiency projects. Indiana’s State Revolving Fund (SRF) has received proposals from municipalities requesting a portion of those funds to implement Green infrastructure at their local wastewater treatment plants. The City of Columbus is proposing to install permeable pavement and a tree canopy and the City of Goshen would like funds to incorporate a rain water harvesting system in order to reduce the amount of stormwater run-off entering local water bodies.
In the industry sector, water treatment additives and treatment technology are the most common mechanisms for treatment. Red Gold, a tomato processing facility in Geneva, has implemented a Green infrastructure approach to treat process wastewater by filtering it through a three-stage wetland system prior to discharging to Loblolly Creek. This approach is approved and permitted through the facility’s National Pollutant Discharge Elimination System (NPDES) permit through IDEM.
Implementation of Green infrastructure will depend heavily on partnerships between local, state and federal regulators in order to amend stormwater regulations to support water quality improvements. Long-term control plans can incorporate Green infrastructure to manage the amount stormwater run-off entering storm drains thus reducing combined sewer overflows. Local ordinances can be revised to emphasize green design, preserving natural vegetation and reducing impervious surfaces. Communities can provide hands-on education to citizens on using Green infrastructure as stormwater treatment to reduce pollutant loads to their local watershed. Building off the success of polit projects and demonstrations will lead to future implementation of Green infrastructure across Indiana.
If you have questions regarding Green infrastructure and would like to speak with a CTAP staff member please contact (800) 988-7901 or, via email, ctap at idem.in.gov. To obtain more details on Green infrastructure the following websites are useful: