Abstracts of Current Research:- Suspended sediment load, bed load, and dissolved load yields
from a semiarid drainage basin: A 15-year study: A 15-year record for the semiarid upland Eshtemoa catchment provides a basis for
estimating the efflux of water, sediment, and solutes in a type of environment for which
there is a dearth of information. Average annual runoff was 5.4 mm, giving a runoff
coefficient of 2.1%. Average annual yields were 275 Mg km2 for suspended sediment,
15.3 Mg km2 for bed load, and 0.6 Mg km2 for dissolved load, though distinct seasonal
differences are identified and related to the prevalence of cellular, convectively
enhanced storms in autumn and spring and frontal storms in winter. The majority of the
average annual total sediment and solute yield of 291 Mg km2 is generated by as few as
8 of the 74 flow events of the 15-year record. The relative importance of bed load and
the consequent ranking of the load components as suspended load - bed load -
dissolved load distinguishes this dryland environment from its humid counterparts.
- Extreme rates of channel incision and the shape evolution in response to a continuous, rapid base level fall, the Dead Sea, Israel.: In nature, opportunities are limited for recording the response to a rapid ongoing base-level fall and for examining its effects on channel evolution during the process. Following a dramatic base-level fall, the natural laboratory area of the Dead Sea offers such an opportunity. Classical shape evolution models of incised channels
describe the response to an "impulse" type base-level drop after it became stabilized. The Dead Sea delineates during its continuous level drop a different mode of adjustment from those previously conceptualized. - Processes of Initiation of Motion Leading to Bedload Transport in Gravel-bed Rivers: Transport processes that lead to the initiation of bedload motion in gravel-bed rivers have not yet been clarified. We report patch- and grain-scale processes involved in the initiation of bedload motion in a natural gravel-bed stream as observed through a series of video experiments. With increasing flow strength, the stages of initiation of motion that have been identified are 1) within-patch grain instability (grain vibration, pivoting and grain-scale rolling), (2) within-patch gyratory step-and-rest motion, and (3) general sediment motion involving downstream transport from an individual patch and the throughput of grains inherited from upstream.
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Publications:- Bowman, D., Svoray, T., Devora, S., Shapira, I. and Laronne, J.B. . Extreme rates of channel incision and the shape evolution in response to a continuous, rapid base level fall, the Dead Sea, Israel. Geomorphology 114: 227-237 (2010)
- Alexandrov, Y., Cohen, H., Laronne, J.B. and Reid, I.. . Total water-borne material losses from a semi-arid drainage basin: a 15-year study of the dynamics of suspended, dissolved and bed loads. Water Resources Research 45: (2009)
- Oda, A. Mizuyama, T., Laronne, J.B., Nonaka, M., Matsuoka, M.. Flume experiments to examine hydrophone characteristics. Journal Japan Society Erosion Control Engineering 60(5): 66-71 (2008)
- Alexandrov Y., Balaban, N., Bergman, N., Chocron, M., Krispil, S,. Laronne, J.B., Powell, D.M., Reid, I. and Wener-Frank, I.. Differentiated suspended sediment transport in headwater basins of the Besor catchment, northern Negev. Isreal Journal of Earth Sciences 57: 177-188 (2008)
- Habersack, H.M., Seitz, H and Laronne, J.B.. Spatio-temporal variability of bedload discharge in a large Alpine River. Geodinamika Acta 21/1-2: 67-79 (2008)
- Liébault, F. and Laronne, J.B.. Factors affecting the evaluation of bedload transport in gravel-bed rivers using scour chains and painted tracers: the case of the Esconavette Torrent. Geodinamika Acta 21/1-2: 23-34 (2008)
- Cohen, S., Svoray, T., Laronne, J.B. and Alexandrov, Y.. FuDEM: a temporally dynamic catchment scale soil erosion model based on fuzzy logic. Journal of Hydrology 356 (1-2) DOI 10.1016/j.jhydrol.2008.04.010: 185-198 (2008)
- Garcia, C., Cohen, H., Reid, I., Rovira., A., Ubeda, X. and Laronne, J.B.. Processes of initiation of motion leading to bedload transport in gravel-bed rivers. Geophysical Research Letters 34: doi:10.1029/2006GLO28865, 2007: L06403, 2007 (2007)
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