Aquifer A geologic formation(s) such as the bedrock that underlies the soil surface. These rock formations store and/or transmit water to springs and wells which provide drinking water. An aquifer typically refers to those bedrock formations that can yield sufficient water to constitute a usable supply for people's uses.

Biodiversity The variety of life in all its forms, levels, and combinations, including ecosystem diversity, species diversity, and genetic diversity.

Biotic Resources The factors of biodiversity which are of direct, indirect, or potential use to humanity. These are of or relate to life; they are caused or produced by living beings and are therefore renewable.

Comprehensive Plan The written product of a process, based on citizen participation, that identifies the goals, objectives, principles, guidelines, policies, standards, and strategies for the growth, development, and protection of the community. The Pennsylvania Municipalities Planning Code requires that a comprehensive plan include a plan for the protection of natural and historic resources.

Cultural Resources Sites or structures, including their landscape settings, which exemplify the cultural, archeological, architectural, economic, social, political, or historic heritage of the community.

Development Right A loose term, generally meaning the individual right to develop land; it is one of a larger bundle of rights attributable to property ownership. Besides development rights, land ownership also includes rights pertaining to agriculture, surface water, and groundwater.

Easement A legal agreement between a property owner and a land trust, other non profit organization, or governmental institution that protects the conservation, scenic, or historic value of the parcel by permanently limiting some of the land’s uses.

Ecosystem A system consisting of a community of animals, plants and microorganisms and the physical and chemical environment to which they interrelate.

Fauna All the animal life in a particular region.

Floodplain A land area adjacent to one or more rivers and streams and subject to recurring flooding. The boundary of this area is determined by the 100-year floodplain, as delineated by the Federal Emergency Management Agency. The term "100-year flood" is a statistical designation meaning there is a 1-in-100 (1%) chance that a flood this size will happen during any year.

Flora All the plant life in a particular region.

Greenways Corridors of land that serve as linkages among high priority natural resources or manmade features. They can be either land or water based and serve a variety of functions and benefits, including community revitalization and economic development, natural resource conservation, environmental protection, wildlife habitat, and migration.

Groundwater Water naturally stored underground in aquifers, or that flows through and saturates soil and rock, supplying springs and drinking water or other wells.

Headwaters The land area or watershed that drains to “first-order streams,” which are the small streams that first define water flowing on the ground from rainfall, snowmelt, or springs.

Historic Resources Any building, structure, object, district, area, or site that is significant in the history, architecture, archaeology, or culture of the community.

Hydric Soils Soil that is saturated or flooded long enough during the growing season to develop conditions which are indicative of wetlands.

Land Trust A non profit organization formed for the express purpose of holding land for its conservation, historic preservation, and wildlife protection, among other purposes.

Natural Resources Materials that occur in nature and are essential or useful to humans, such as water, air, land, forests, fish and wildlife, topsoil, and minerals.

Open Space Open space includes any area that is characterized by natural or cultural scenic beauty or whose condition or quality is such that it will enhance the present or potential value of surrounding developed lands, or enhance the conservation of natural or scenic resources. Open space may include publicly or privately held undeveloped lands used for the preservation or protection of natural or cultural resources.

Open Space Plan The written product of a process, based on citizen participation, designed to identify open-space resources and prioritize their protection for the future good of a community. The Plan also recommends actions needed to meet goals for open space protection.

Preserved Land Land that has been permanently protected through a legal mechanism (e.g., easement) that limits future uses for open space purposes.

Riparian Buffer Vegetated (ideally wooded) areas adjacent to streams, ponds, and other waterways that protect those water resources from pollution, prevent erosion of the banks, provide wildlife food and cover, and shade the adjacent water, moderating temperatures for aquatic species.

Scenic Resources Landscape patterns and features which are visually or aesthetically pleasing and which therefore contribute to and enhance the community. Scenic resources are not definable in isolation from other resource categories. Historic sites and buildings, archaeological sites, woodlands, surface water bodies, shorelines, rural roads, etc. may be part of, or stand separate from, larger geographic areas identified as scenic.

Surface Water Water that sits or flows above the earth, including lakes, oceans, rivers, streams, and ponds.

Sedimentation The accumulation of earthy matter (soil and mineral particles) washed into a river, stream, wetland, or other water body, normally by erosion, and which settles on the bottom. The gradual build up of sedimentation tends to choke channels and rivers, inhibiting plant and fish life.

(Sub)Urban Sprawl A pattern and pace of land development in which the rate of land consumed for (sub)urban purposes exceeds the rate of population growth using the developed land. Sprawl results in an inefficient and consumptive use of land and its associated resources.

Watershed A region defined by patterns of stream drainage. A watershed includes all the land that contributes (i.e., drains) water to a particular stream or river, while a headwaters watershed drains to the smallest streams in the larger stream system.

Wetlands Areas where water covers the soil, or is present either at or near the surface of the soil all year or for varying periods of time during the year, including during the growing season.

Woodland A tree mass or plant community in which tree species are dominant and tree branches form a complete or nearly complete canopy.

Sources for the above terms include:
The Brandywine Conservancy
CGIS at Towson University
The Chadds Ford Township Open Space Committee
The Maryland Environmental Trust’s Land Conservation Center
Land Trust Alliance
Pace University School of Law