Topographic Setting Code
# National Water Information System
# Date Retrieved: USGS Water Data for the Nation Help System
gw_ref_cd gw_ref_nm gw_ref_ds
1s 16s 102s
A Alluvial fan Stream deposit of loose rock material where it issues from a narrow mountain valley upon a plain.
B Playa Undrained desert basin in which water accumulates and is quickly evaporated.
C Stream channel Bed in which a natural stream of water runs.
D Local depression An area that has no external surface drainage.
E Dunes Mounds and ridges of windblown, or eolian sand.
F Flat surface May be part of a larger feature, such as a plateau, plain, or pediment.
G Flood plain Smooth land surface adjacent to a river channel that is flooded when the river overflows its banks.
H Hilltop Upper part of a hill or ridge above a well-defined break in slope.
K Sinkhole Depression that results from the dissolving of soluble rocks and collapse into the solution cavity.
L Lake or Swamp Inland lake, swamp, or marsh where the ground may be saturated or water stands above the land surface.
M Mangrove swamp Tropical or subtropical marine swamp characterized by abundant mangrove trees.
O Offshore Site along a coast or estuary that is continuously submerged.
P Pediment Plain of combined erosion and deposition that forms at the foot of a mountain range.
S Hillside Sloping side of hill, the area between the hilltop and valley flat.
T Alluvial terrace Generally a flat surface, usually parallel to but elevated above a stream valley or coast line.
U Undulating Topography is characteristic of areas which have many small depressions and low mounds.
V Valley flat Low flat area between the valley walls and bordering a stream channel.
W Upland draw Small natural drainageway