Abstract
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.
| Original language | English |
|---|---|
| Pages (from-to) | 1348-1362 |
| Number of pages | 15 |
| Journal | Earth Surface Processes and Landforms |
| Volume | 46 |
| Issue number | 7 |
| DOIs | |
| State | Published - 15 Jun 2021 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2021 John Wiley & Sons Ltd.
Funding
The long‐term Nahal Yael experimental watershed was established by the late Prof. Asher Schick. The late Prof. David Sharon was key in our understanding of the meteorological aspects of the region. The research was initially funded in 1965 by the US Army Research Office. This was years before it became more common to conduct and fund long‐term research. Schick's efforts were encouraged by the late Reds Wolman, Luna Leopold, and Ran Gerson, and by many other dear colleagues such as Bill Bull; this manuscript is, in part, the result of field visits and classes we had decades ago in Nahal Yael and nearby watersheds with all these giants. Maintaining the experimental watershed was funded, mainly to Asher Schick during the many years by the Israel Science Foundation, the US–Israel Binational Science Foundation, Israel Ministries of Agriculture and Infrastructure, and The Hebrew University of Jerusalem. Data were collected by numerous devoted students and researchers working under very harsh conditions, even without funding; there are too many of them to be mentioned individually, but first among them is Dr. Tamir Grodek. Partial monitoring continues today by the Dead Sea–Arava Science Center. We thank the anonymous reviewers for their constructive suggestions, which helped to sharpen the manuscript and put it in a better perspective. The long-term Nahal Yael experimental watershed was established by the late Prof. Asher Schick. The late Prof. David Sharon was key in our understanding of the meteorological aspects of the region. The research was initially funded in 1965 by the US Army Research Office. This was years before it became more common to conduct and fund long-term research. Schick's efforts were encouraged by the late Reds Wolman, Luna Leopold, and Ran Gerson, and by many other dear colleagues such as Bill Bull; this manuscript is, in part, the result of field visits and classes we had decades ago in Nahal Yael and nearby watersheds with all these giants. Maintaining the experimental watershed was funded, mainly to Asher Schick during the many years by the Israel Science Foundation, the US–Israel Binational Science Foundation, Israel Ministries of Agriculture and Infrastructure, and The Hebrew University of Jerusalem. Data were collected by numerous devoted students and researchers working under very harsh conditions, even without funding; there are too many of them to be mentioned individually, but first among them is Dr. Tamir Grodek. Partial monitoring continues today by the Dead Sea–Arava Science Center. We thank the anonymous reviewers for their constructive suggestions, which helped to sharpen the manuscript and put it in a better perspective.
| Funders | Funder number |
|---|---|
| Dead Sea–Arava Science Center | |
| Israel Ministries of Agriculture and Infrastructure | |
| Army Research Office | |
| United States-Israel Binational Science Foundation | |
| Hebrew University of Jerusalem | |
| Israel Science Foundation |
Keywords
- Dead Sea rift
- Negev
- alluvial fan
- arid
- bedload
- desert floods
- flood-integrated stream power
- geomorphic work
- hyperarid
- sediment transport
- sediment yield