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Variability of sediment removal in a semiarid watershed
Author(s) -
Graf William L.
Publication year - 1983
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr019i003p00643
Subject(s) - sediment , hydrology (agriculture) , erosion , alluvium , watershed , stream power , channel (broadcasting) , structural basin , geology , drainage basin , sediment transport , alluvial fan , sinuosity , sedimentary budget , environmental science , geomorphology , geography , geotechnical engineering , machine learning , computer science , cartography , engineering , electrical engineering
Field and documentary data from Walnut Gulch Watershed, an instrumented semiarid drainage basin of approximately 150 km 2 (57 mi 2 ) in southeastern Arizona, show that 83% of the alluvium removed from the basin during a 15‐year erosion episode beginning about 1930 was excavated from the highest‐order stream. The amount of alluvium removed in the erosion episode would have been equal to a covering of about 4 cm (1.6 in) over the entire basin. The rate of sediment removal during the erosion episode was 18 times greater than the rate of present channel sediment transport. Production of sediment from slopes and channel throughput at present rates are approximately equal, and refilling will not occur under present conditions. The channel forms left by the massive evacuation of sediment impose controls on the spatial distribution of tractive force and total stream power that make renewed storage of sediment likely in only a few restricted locations. Modern instrumented records of a decade or more provide an inadequate perspective on long‐term sediment movement.