1. Water regime influenced by oceanic tides, and salinity due to
    ocean-derived salts 0.5‰ or greater.
   2. Semi-enclosed by land, but with open, partly obstructed or
      sporadic access to the ocean. Halinity wide-ranging because of
      evaporation or mixing of seawater with runoff from land . . . . ESTUARINE
   2. Little or no obstruction to open ocean present. Halinity
      usually euhaline; little mixing of water with runoff from land . . . . .3
     3. Emergents, trees, or shrubs present . . . . . . . . . . . . . ESTUARINE
     3. Emergents, trees, or shrubs absent . . . . . . . . . . . . . . . MARINE
 1. Water regime not influenced by ocean tides, or if influenced by
      oceanic tides, salinity less than 0.5‰
   4. Persistent emergents, trees, shrubs, or emergent mosses cover
      30% or more of the area  . . . . . . . . . . . . . . . . . . . PALUSTRINE
   4. Persistent emergents, trees, shrubs, or emergent mosses cover
      less than 30% of substrate but nonpersistent
      emergents may be widespread during some seasons of year  . . . . . . . .5
     5. Situated in a channel; water, when present, usually flowing . .RIVERINE
     5. Situated in a basin, catchment, or on level or sloping ground;
        water usually not flowing  . . . . . . . . . . . . . . . . . . . . . .6
          6. Area 8 ha (20 acres) or greater . . . . . . . . . . . . LACUSTRINE
          6. Area less than 8 ha . . . . . . . . . . . . . . . . . . . . . . .7
             7. Wave-formed or bedrock shoreline feature present or
                water depth 2 m (6.6 feet) or more   . . . . . . . . LACUSTRINE
             7. No wave-formed or bedrock shoreline feature present and
                water less than 2 m deep . . . . . . . . . . . . . . PALUSTRINE

  1. During the growing season of most years, areal cover by vegetation is 
     less than 30%.
     2. Substrate a ridge or mound formed by colonization of sedentary 
        invertebrates (corals, oysters, tube worms)  . . . . . . . . . . . REEF
     2. Substrate of rock or various-sized sediments often occupied by 
        invertebrates but not formed by colonization of sedentary 
        invertebrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
       3. Water regime subtidal, permanently flooded, intermittently
          exposed, or semipermanently flooded. Substrate usually not soil . . 4
         4. Substrate of bedrock, boulders, or stones occurring singly
            or in combination covers 75% or more of the area . . . .ROCK BOTTOM
         4. Substrate of organic material, mud, sand, gravel, or 
            cobbles with less than 75% areal cover of stones, boulders, 
            or bedrock . . . . . . . . . . . . . . . . . .UNCONSOLIDATED BOTTOM
       3. Water regime irregularly exposed, regularly flooded,
          irregularly flooded, seasonally flooded, temporarily flooded,
          intermittently flooded, saturated, or artificially flooded.
          Substrate often a soil . . . . . . . . . . . . . . . . . . . . . . .5
         5. Contained within a channel that does not have permanent
            flowing water (i.e., Intermittent Subsystem of Riverine 
            System or Intertidal Subsystem of Estuarine System) . . . STREAMBED
         5. Contained in a channel with perennial water or not
            contained in a channel . . . . . . . . . . . . . . . . . . . . . .6
           6. Substrate of bedrock, boulders, or stones occurring singly
              or in combination covers 75% or more of the area . . .ROCKY SHORE
           6.  Substrate of organic material, mud, sand, gravel, or
               cobbles; with less than 75% of the cover consisting
               of stones, boulders, or bedrock . . . . . . UNCONSOLIDATED SHORE
   1. During the growing season of most years, percentage of area covered 
      by vegetation 30% or greater.
     7. Vegetation composed of pioneering annuals or seedling 
        perennials, often not hydrophytes, occurring only at time of 
        substrate exposure . . . . . . . . . . . . . . . . . . . . . . . . . .8
       8. Contained within a channel that does not have permanent
          flowing water . . . . . . . . . . . . . . . . . STREAMBED (VEGETATED)
       8. Contained within a channel with permanent water, or not
          contained in a channel . . . . . . . UNCONSOLIDATED SHORE (VEGETATED)
     7. Vegetation composed of algae, bryophytes, lichens, or vascular
        plants that are usually hydrophytic perennials . . . . . . . . . . . .9
       9. Vegetation composed predominantly of nonvascular species . . . . . 10
           10. Vegetation macrophytic algae, mosses, or lichens growing
               in water or the splash zone of shores . . . . . . . .AQUATIC BED
           10. Vegetation mosses or lichens usually growing on organic
               soils and always outside the splash zone of shores . . . . . . .
               . . . . . . . . . . . . . . . . . . . . . . .MOSS-LICHEN WETLAND
       9. Vegetation composed predominantly of vascular species . . . . . . .11
           11. Vegetation herbaceous . . . . . . . . . . . . . . . . . . . . 12
              12. Vegetation emergents  . . . . . . . . . . . .EMERGENT WETLAND
              12. Vegetation submergent, floating-leaved, or floating . . . . .
                  . . . . . . . . . . . . . . . . . . . . . . . . . AQUATIC BED
           11. Vegetation trees or shrubs . . . . . . . . . . . . . . . . . .13
              13. Dominants less than 6 m (20 feet) tall . .SCRUB-SHRUB WETLAND
              13. Dominants 6 m tall or taller . . . . . . . . FORESTED WETLAND