Low Impact Development Practices, Terms and Definitions

Compost: Decomposed organic material added to soil that increases its capacity to hold water and nourish plants.

Downspout Disconnection: To disconnect a building's roof drains from the storm sewer system and re-direct to lawns, rain gardens and swales. Always check with local codes before disconnecting downspouts.

Drought Tolerant: Plants that need little or no watering once established.

Green roof (ecoroof): Vegetated roof system that reduces runoff, improves air quality, provides wildlife habitat, saves energy and lasts longer than a conventional roof.

Green Street: Street designed to capture, absorb and filter runoff using rain gardens, planters, swales, porous pavement, tree canopy and other methods.

Impervious Surface: Hard surfaces such as roofs and pavement that prohibit water from soaking into the ground.

Invasive Plants: Aggressive plants that crowd out native plants for water, sunlight and nutrients and harm the environment, economy and human health.

Low Impact Development: Methods that preserve natural resources and collect and clean stormwater runoff on site to protect and improve water quality.

Minimize Hard Surfaces: To reduce the area covered by buildings, roofs, roads, parking lots and sidewalks.

Mulch: Material such as bark chunks, wood chips, and stone that is spread on soil to retain moisture, discourage weeds and protect against erosion.

Native Plants: Plants that need little or no fertilizer or care once established, provide wildlife habitat, and occur historically in an area.

Naturescaping: Landscaping with native plants to restore natural systems and attract native insects, birds and wildlife.

Porous Pavement: Surface to walk, drive or park on that reduces stormwater runoff by allowing water to soak into the ground. Examples are permeable pavers, pervious concrete, porous asphalt and gravel.

Rain Garden: Planted, bowl-shaped area designed to collect and absorb runoff and filter out pollutants.

Rainwater Harvesting (rain barrel): To collect and store rainwater for landscape watering, toilet flushing and other uses.

Stormwater Planter: Structural container with soil and plants built to collect and slow runoff; it may have a drain for excess water.

Stormwater Runoff: Rainfall and snowmelt that "runs off' instead of seeping into the ground. Runoff carries pollutants to waterways and may degrade streams and cause unnatural flooding.

Sustainable (low impact) Site Design: Building and construction techniques that lessen the impact on the environment and protect and preserve open spaces, natural resources and habitat.

Swale: Long, planted, open channel that carries, slows and absorbs stormwater and filters out pollutants.

Tree Preservation, Planting and Protection: To preserve and protect trees by fencing, limiting soil compaction, guarding from animal damage and other practices. Trees capture rain, filter pollutants, provide shade and cool air, improve air quality and provide habitat.

Watershed: Land that drains water to a stream, river, pond, lake or ocean.

Water-wise Gardening (xeriscaping): To minimize water use by choosing plants appropriate to the site that need little watering.