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Flood‐duration‐integrated stream power and frequency magnitude of >50‐year‐long sediment discharge out of a hyperarid watershed
Author(s) -
Lekach Judith,
Enzel Yehouda
Publication year - 2021
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.5104
Subject(s) - stream power , flood myth , hydrology (agriculture) , sediment , watershed , alluvium , structural basin , return period , geology , drainage basin , environmental science , magnitude (astronomy) , hydrograph , floodplain , sediment transport , physical geography , geography , geomorphology , archaeology , physics , geotechnical engineering , cartography , machine learning , astronomy , computer science
Determining sediment discharge out of watersheds is a global, long‐term challenge. In the vast, usually data‐poor, hyperarid regions of the world, this is a greater challenge. Here, we present a unique, decades‐long dataset of individual floods and their respective sediment discharge out of Nahal Yael, an experimental, well‐instrumented, hyperarid (~25–30 mm year −1 ) watershed in southern Israel. The high correlation between directly measured sediment yield by discrete individual floods and their respective total energy, represented by flood‐integrated stream power (FISP), serves here as a rating curve. Using this rating curve, the 51‐year‐long series of FISP in Nahal Yael, calculated from the detailed individual flood hydrographs, was converted into a series of sediment yield by these floods. This, in turn, allows determining the long‐term frequency‐magnitude of sediment exported out of this hyperarid basin. This can assist in landscape evolution modeling, in testing impacts of flood frequency changes enforced by altered regional climatology, and hint at changes needed in forming the observed alluvial fans. We conclude that, at the decadal scale, moderate floods are the most effective in terms of total sediment transport. However, the recurrence intervals of these moderate hyperarid floods are longer than in temperate regions and reach 5–10 years.