4.2 Aquatic Communities
from the local underground drainage system and develop on the surface or in caves (Fleury 2009) . Tey are made up of groundwater that has infltrated at diferent times, from diferent places, and potentially under diferent conditions than currently exist (van der Kamp 1995) . In contrast, seeps discharge to a larger area than a spring (McGinley 2013) . Seepage springs are a difuse discharge of gravity-fed water where the land surface is wet compared to surround- ing areas, but there is no observable fow (Culver et al. 2012) . Subterranean water develops in permeable layers of soil, sand, and rock. A subterranean system that carries groundwater in sufcient quantity to provide usable water supplies is called an aquifer (Hynes 1983; Barnes-Svarney and Svarney 2004; Kokkonen et al. 2011). Coastal Plain groundwater is found primarily in porous sand and limestone (carbonate rock), and is regionally classifed as being shallow unconfned (surfcial) aquifers or deeper confned aquifers (Smith and Chapman 2005; USGS 2012a; Denver et al. 2014) . All aquifers have an impermeable layer beneath them that stops the groundwater from infltrating further. When the layers above it are permeable, it is an unconfned aquifer and when the permeable layer occurs between two impermeable layers, it is a confned aquifer (Domenico and Schwartz 1998; McGinley 2013) . Precipitation in aquifer outcrop areas is a major source of recharge to aquifers under predevelopment and present-day conditions (Aucott 1996) . Many of the Coastal Plain aquifers are karst systems that have formed over geologic time scales through the dissolution of carbonate bedrock, resulting in the formation of the caves, sinkholes, springs, and subterranean streams that are typical features of a karst system (Fleury 2009; USGS 2012a) . Aquifers in the central Coastal Plain area are formed from unconsolidated deposits of sand, silt, clay, and limestone (Heath and Spruill 2003) . Aquifers in the Piedmont and Mountain ecoregions are found in Triassic Basin rocks that are covered by regolith (soil, saprolite, alluvium, and colluvium) (USGS 2012a) . Karst systems and other subterranean resources should be considered non-renewable once they have been depleted or degraded, because they are formed by specifc processes that occur over long geologic time periods (Gunn et al . 2000) . 4.2.6.2 Location of Habitat Since aquifers are geological features that are often used for drinking water, supply map- ping information is generally available. Such principal aquifers include the Lower Cape Fear, Upper Cape Fear, Black Creek, Pee Dee, Castle Hayne, Yorktown, Surfcial, and Bedrock aquifers. Minor aquifers in the State include the Lower Cretaceous, Beaufort, and Pungo River (NCDWR 2010b; USGS 2012a) . Potentiometric surface maps for several Coastal Plain ecoregion aquifers are available from the NC Division of Water Resources (2015i) . Springs are generally associated with stream systems, especially headwater streams, and other surface water bodies such as farm ponds.
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2015 NC Wildlife Action Plan
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