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Response of the Ohau River and delta to lake level lowering
Author(s) -
Mosley M. P.
Publication year - 1984
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.3290090209
Subject(s) - aggradation , progradation , delta , hydrology (agriculture) , geology , river delta , stream power , channel (broadcasting) , sediment , drainage basin , alluvium , geomorphology , structural basin , fluvial , geography , geotechnical engineering , facies , electrical engineering , cartography , aerospace engineering , engineering
The response of the Ohau River to a lowering of Lake Benmore of 4 m was monitored during a three‐month period when the river was carrying mean daily flows between 100 and 400 m 3 /s from a power station. Initially, the river degraded by up to 0·8 m for a distance of 1·3 km upstream from the lake, but during the 52‐day period of minimum lake level, the delta and lower channel aggraded by up to 0·4 m. During that period, an estimated 225 000 m 3 of sediment was supplied to the delta, sufficient for rapid progradation of the delta front into the shallow lake and the observed aggradation of the channel and delta surface. Other factors, in this case receiving‐basin geometry and sediment yield, may thus control the response of a river‐delta system to relative base‐level lowering.