Geoscience Reference
In-Depth Information
Hydroperiods
Large Riparian Wetland
Headwater Wetland
Wooded Swamp
G
S
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Figure 4-7.
Drainage ditch in the headwaters of the
Middle Loup River in the Sand Hills of western
Nebraska, United States. Water level is lowered in the
wet meadows and marshes to increase hay production,
and water l ow is accelerated downstream. Photo
by J.S. Aber.
Months
Figure 4-5.
Idealized hydroperiods for wetlands in
three settings in temperate climates, such as the
northeastern United States. GS indicates ground surface
level. Adapted from Welsch et al. (1995).
Figure 4-6.
Marsh-pond complex in the Sand Hills
near Lakeside in western Nebraska, United States (see
Color Plate 4-6). Bright maroon and golden-orange
colors in this pond are presumably caused by
carotenoid pigments of invertebrates, such as brine
shrimp, brine l ies and rotifers, in the hyperalkaline
water typical of the western Sand Hills region (Bleed
and Ginsberg 1990). Kite airphoto by S.W. Aber and
J.S. Aber.
Figure 4-8.
Spring at the head of Trinchero Creek
emerges from a fault in hard sandstone at scene center.
The spring is surrounded by mounds of brook crest
(
Cardamine cordifolia
). Culebra Range, Sangre de
Cristo Mountains, southern Colorado, United States.
Photo by J.S. Aber.
time also decrease the amount of water process-
ing within the wetland (Fig. 4-7).
water in ways that are less obvious and more
difi cult to monitor. Aquifers are underground
formations that both store and transmit water.
The practical manifestations of aquifers are
springs (Fig. 4-8), where ground water comes to
the surface naturally, and man-made wells that
produce water. In most wells, water rises to the
level of the water table below ground and must
be pumped to the surface (Fig. 4-9). In some
cases, the aquifer has sufi cient hydrostatic
4.2 Surface and ground water
The relationship of wetlands to surface water
inl ow and outl ow is often obvious and may be
readily measured in many cases (see Figs. 3-25
and 3-26). Wetlands also interact with ground
