D
DELTA PLAIN
Colin D. Woodroffe
School of Earth and Environmental Sciences, University
of Wollongong, Wollongong, NSW, Australia
Definition
A delta plain is a low-elevation floodplain formed at the
mouth of a river.
Characteristics
A delta plain is one type of low-lying coastal plain,
formed where a river empties into the sea (or, rarely, into
a freshwater body, as in the case of the Selenga Delta,
Figure 1a). Large deltas can generally be subdivided into
an upper deltaic plain influenced primarily by fluvial
processes and a lower deltaic plain, dominated by wave
and tidal processes (Figure 1b). The river flows through
the “active” section, but there is commonly an abandoned
section containing paleochannels marking former river
courses (Wright et al., 1974).
The Red River Delta in northern Vietnam (Figure 1c)
can be differentiated into a river-dominated upper
delta plain where channels are flanked by levées and
meander scroll bars marking former river courses,
a southern wave-dominated section with sequences
of shore-parallel beach ridges, and an eastern
tide-dominated section with numerous tapering tidal
creeks (Mathers and Zalasiewicz, 1999).
Similar near-horizontal alluvial plains can form along
estuaries, sometimes called deltaic-estuarine plains. For
example, coastal lagoons (e.g., Coila Lake, Figure 1d)
and barrier estuaries (e.g., Tuross Lake) become gradually
infilled as fluvial sediment builds a bayhead delta into the
estuarine basin.
Extensive, perennially or seasonally flooded, wetlands
may characterize delta plains in their natural state
(Figure 1a). Megadeltas in southeastern Asia are often the
location for intensive rice cultivation, but also
support megacities (e.g., Hanoi, Figure 1c), many of
which require augmentation of levées for flood
mitigation. The ease with which land can be cleared and
the fertility of soils has encouraged their agricultural use
(e.g., Figure 1d).
M.J. Kennish (ed.), Encyclopedia of Estuaries, DOI 10.1007/978-94-017-8801-4,
© Springer Science+Business Media Dordrecht 2016
DELTA PLAIN
Colin D. Woodroffe
School of Earth and Environmental Sciences, University
of Wollongong, Wollongong, NSW, Australia
Definition
A delta plain is a low-elevation floodplain formed at the
mouth of a river.
Characteristics
A delta plain is one type of low-lying coastal plain,
formed where a river empties into the sea (or, rarely, into
a freshwater body, as in the case of the Selenga Delta,
Figure 1a). Large deltas can generally be subdivided into
an upper deltaic plain influenced primarily by fluvial
processes and a lower deltaic plain, dominated by wave
and tidal processes (Figure 1b). The river flows through
the “active” section, but there is commonly an abandoned
section containing paleochannels marking former river
courses (Wright et al., 1974).
The Red River Delta in northern Vietnam (Figure 1c)
can be differentiated into a river-dominated upper
delta plain where channels are flanked by levées and
meander scroll bars marking former river courses,
a southern wave-dominated section with sequences
of shore-parallel beach ridges, and an eastern
tide-dominated section with numerous tapering tidal
creeks (Mathers and Zalasiewicz, 1999).
Similar near-horizontal alluvial plains can form along
estuaries, sometimes called deltaic-estuarine plains. For
example, coastal lagoons (e.g., Coila Lake, Figure 1d)
and barrier estuaries (e.g., Tuross Lake) become gradually
infilled as fluvial sediment builds a bayhead delta into the
estuarine basin.
Extensive, perennially or seasonally flooded, wetlands
may characterize delta plains in their natural state
(Figure 1a). Megadeltas in southeastern Asia are often the
location for intensive rice cultivation, but also
support megacities (e.g., Hanoi, Figure 1c), many of
which require augmentation of levées for flood
mitigation. The ease with which land can be cleared and
the fertility of soils has encouraged their agricultural use
(e.g., Figure 1d).
M.J. Kennish (ed.), Encyclopedia of Estuaries, DOI 10.1007/978-94-017-8801-4,
© Springer Science+Business Media Dordrecht 2016