12G
DE
: Le
vel I
Inve
ntor
y Fi
eld
Gui
de
CharacteristicsSpringsPeatlands, including fens (groundwater
dependent)
Other wetlands (groundwater dependent)
HydrologyCompletely groundwater dependent
Minerotrophic; always groundwater dependent
Minerotrophic; depend on groundwater, precipitation, and
sometimes stream inflow
Water table positionAt ground surface or, for artesian, a
piezometric surface above the ground surface
At or slightly below surface, or piezometric surface above the
ground
Above or below ground surface; can fluctuate dramatically; can
have periodic standing water
Soils and peat or muck depths
Mostly mineral soils; sometimes a small accumulation of peat
Accumulation of peat or muck up to several meters; little or no
mineral soil within plant-rooting zone for fens
Usually little or no peat or muck accumulation; sometimes
wood-rich peat
Redox conditionsaOxic to anoxic depending on geochemistry and
residence time of water in aquifer
Anoxic slightly below the surface, leading to the accumulation
of peat or muck
Temporary soil anoxia during times of high water table or
standing water
Water movement within GDEs
Standing or flowing waterSlow to imperceptible flow on
surface
Periodic standing or flowing water
Table 3.—Important GDE characteristics and the GDE types covered
by this field guide.
a Redox (short for REDuction-OXidation) conditions describe a
key chemical characteristic in hydrologic systems that controls the
availability of many elements and the propensity of the system to
support the accumulation of organic matter, such as peat and muck.
At the ground surface, redox conditions are often controlled by the
availability of oxygen.
13G
DE
: Le
vel I
Inve
ntor
y Fi
eld
Gui
de
CharacteristicsSpringsPeatlands, including fens (groundwater
dependent)
Other wetlands (groundwater dependent)
Table 3.—Important GDE characteristics and the GDE types covered
by this field guide. (continued)
Water chemistryHighly variable; from acidic to basic,
temperatures vary, can be thermal, can be saline
Minerotrophic, acidic (poor fens) to basic (rich fens); can be
iron rich or calcareous
Highly variable, from acidic to basic
VegetationGraminoids, forbs, shrubs, bryophytes, and trees;
variable amount of wetland vegetation
Bryophytes, graminoids, and low shrubs; lichens; sometimes
trees; always wetland vegetation
Tall woody plants and forbs (swamps) or emergent graminoids and
floating aquatic macrophytes (marshes); mostly wetland
vegetation