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V,7i1h> llecunicnt 1:ci loyal aLC _, u: component or portion of their Life- history (i.e., reproduction, rearing and development, feeding, etc). Class _ Aquifer means an aquifer that is surficial or shallow, permeable, and is highly vulnerable to contamination. Class 1 aquifers include: (1) Unconsolidated Aquifers (Class Ia) that consist of surficiai, unconsolidated, and permeable alluvial, terrace, outwash, beach, dune and other similar. deposits. These aquifers generally contain layers of sand and gravel that, commonly, are interbedded to some degree with silt and clay. Not all Class Ia aquifers are important water - bearing units, but they are likely to be both permeable and vulnerable. The only natural protection of these aquifers is the thickness of the unsaturated zone and the presence of fine - grained material; [[Page 128]] (2) Soluble and Fractured Bedrock. Aquifers (Class Ib). Lithologies in this class include limestone, dolomite, and, locally, evaporitic units that contain documented karst features or solution channels, regardless of size. Generally these aquifers have a wide range of permeability. Also included in this class are sedimentary strata, and metamorphic and igneous (intrusive and extrusive) rocks that are significantly faulted, fractured, or jointed. In all cases groundwater movement is largely controlled by secondary openings. Well yields range widely, but the important feature is the potential for rapid vertical and lateral ground water movement along preferred pathways, which result in a high degree of vulnerability; (3) Semiconsolidated Aquifers (Class Ic) that generally contain poorly to moderately indurated sand and gravel that is interbedded with clay and silt. This group is intermediate to the unconsolidated and consolidated end members. These systems are common in the Tertiary age rocks that are exposed throughout the Gulf and Atlantic coastal states. Semiconsolidated conditions also arise from the presence of intercalated clay and caliche within primarily unconsolidated to poorly consolidated units, such as occurs in parts of the High Plains Aquifer; or (4) Covered Aquifers (Class Id) that are any Class I aquifer overlain by less than 50 feet of low permeability, unconsolidated material, such as glacial till, lacustrian, and loess deposits. Class IIa aquifer means a Higher Yield Bedrock Aquifer that is consolidated and is moderately vulnerable to contamination. These aquifers generally consist of fairly permeable sandstone or conglomerate that contain lesser amounts of interbedded fine grained clast.ics (shale, s.iltstone, mudstone) and occasionally carbonate units. In general, well yields must exceed 50 gallons per minute to be included in this class. Local fracturing may contribute to the dominant primary porosity and permeability of these systems. Community Water System (CWS) means a public water system that serves at least 15 service connections used by year -round residents of the area or regularly serves at least 25 year -round residents. Critically imperiled species or ecological community (habitat) means an animal or plant species or an ecological community of extreme rarity, based on The Nature Conservancy's Global Conservation Status Rank. There are generally 5 or `ewer occurrences, or very few remaining individuals (less than 1,000) or acres (less than 2,000). These species and ecological communities are extremely vulnerable to extinction due to some natural or man- made factor. Depleted marine mammal species means a species that has been identified and is Protected under the Piarine Mammal Protection Act of 1972, as amended (M?PA) (16 U.S.C. 1361 et seq.). The term —depleted" refers to marine mammal species that are listed as threatened or endangered, or are below their optimum sustainable populations (16 U.S.C. 1362). The term —marine mammal" means —any mammal which is morphologically adapted to the marine environment (including sea otters http : / /icwebgatc.access.gpo.gov /cgi -bin /get- circ {- 9 - 9/23/02