Chapter 4 Habitats
is a confined 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 specific processes that occur over long geologic time periods (Gunn et al . 2000) . 4.2.6.2 Location of Habitat Because aquifers are geological features that are often used for drinking water, supply mapping information is generally available. Such principal aquifers include the Lower Cape Fear, Upper Cape Fear, Black Creek, Pee Dee, Castle Hayne, Yorktown, Surficial, and Bedrock aquifers. Minor aquifers in the state include the Lower Cretaceous, Beaufort, and Pungo River (NCDEQ 2010; USGS 2012a) . Potentiometric surface maps for several Coastal Plain ecoregion aquifers are available from the Division of Water Resources groundwater data website (NCDEQ 2025a,b) . Springs are generally associated with stream systems, especially headwater streams, and other surface water bodies such as farm ponds. 4.2.6.3 Problems Affecting Habitats One of the most important issues concerning groundwater systems is the increasing demand for water supplies due to growth and urbanization (Land et al. 2004) . Groundwater extraction to meet this demand is often at unsustainable rates (Fleury 2009) and results in declining water levels, saltwater encroachment (in Coastal Plain systems), dewatering, and land subsidence (e.g., sink holes) (Land et al. 2004; Fleury 2009) . Groundwater pressure can drop when there is rapid and excessive drawdown of an aquifer and the pore space holding the groundwater shrinks. This leads to compaction of the aquifer at depth (Fleury 2009) . Voids can form in the soils and porous rock that once held water, which causes subsidence and collapse of the land surface (Patton and DeHan 1998; Fleury 2009) . According to the USGS, groundwater withdrawals from the Castle Hayne aquifer have caused land subsidence measuring as large as 7 inches and has been documented (during the 33-year period from 1935–68) in the central Coastal Plain of North Carolina. Overall water-level declines are estimated to be as much as 20 feet near pumping centers (McSwain et al. 2014; USGS 2014b) .
Mining operations can remove notable features from the landscape and alter the hydraulic gradients that contribute to groundwater systems. Quarrying often reduces spring discharge,
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2025 NC Wildlife Action Plan
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