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Controls on bedrock channel incision along nahal paran, Israel
Author(s) -
Wohl Ellen E.,
Greenbaum Noam,
Schick Asher P.,
Baker Victor R.
Publication year - 1994
Publication title -
earth surface processes and landforms
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.294
H-Index - 127
eISSN - 1096-9837
pISSN - 0197-9337
DOI - 10.1002/esp.3290190102
Subject(s) - geology , stream power , canyon , bedrock , geomorphology , aggradation , tributary , lithology , alluvium , denudation , channel (broadcasting) , structural basin , tectonics , hydrology (agriculture) , sediment , fluvial , paleontology , geography , electrical engineering , cartography , geotechnical engineering , engineering
Nahal Paran drains 3600 km 2 of Egypt's Sinai peninsula and Israel's Negev Desert. Much of the channel is alluvial, but a canyon 10·5 km long has been incised into Late Cretaceous chert and dolomite in the lower portion of the basin. Slackwater deposits and paleostage indicators preserved within the canyon record approximately 10 floods of 200 to 2500 m 3 s −1 over a period of at least 350 years. Step‐backwater simulations of flood‐flow hydraulics indicate extreme variations in stream power per unit area along the length of the canyon, and associated variability in energy expenditure and sediment transport. These variations reflect channel cross‐sectional morphology. The greatest values of stream power occur along the lower half of the study reach, in association with three pronounced knickpoints and an inner channel. The locations of these features reflect the exposure of thick, resistant chert layers along the channel. The presence of several similar, but buried and inactive, knickpoints along the upper study reach indicates that the locus of most active channel incision has shifted with time, probably in response to baselevel changes associated with tectonic activity along the Dead Sea Rift. Thus, the rate and manner of channel incision along the canyon of Nahal Paran are controlled by lithologic variability and tectonic uplift as they influence channel morphology and gradient, which in turn influence hydraulics and sediment transport.