Fluvial Sediment Yields in Hyper-Arid Areas, Exemplified by Nahal Nehushtan, Israel

Abstract

Floods rarely occur in hyper-arid deserts and little is known about the magnitude and frequency of sediment delivery from their basins, despite their importance to changes to the landscape, infrastructures and engineering activities. Sediment yield from the Nahal Nehushtan watershed (11.9 km2) located in the Timna Valley in southern Israel was determined by assessing stratigraphic sections in its 60-year reservoir deposits. Stratigraphic correlation between event couplets allowed for quantification of sediment yields representing 13 former flow and flood events. Based on the sediment volume in the reservoir, the 29.8 t km−2 year−1 average specific sediment yield is one of the lowest among other studied warm deserts. Among the event layers, the thickest layer, deposited by a flash flood caused by a single short rain event, contributed 31% of the total sediment yield. Based on event reservoir sedimentation from watersheds located in several hyper-arid areas in the Middle East and North America, we demonstrate that sediment yield increases with drainage area as expected and mean annual sediment yield increases in hyper-arid areas with flood frequency. Our quantitative results, together with previous studies of hyper-arid areas, provide complementary evidence of fluvial sediment transport—the main landscape designer in hyper-arid fluvial landscapes.

Introduction to the Silala River and its hydrology

“…Hydrological and hydrogeological data in arid regions typically are limited and of poor quality (Armoza‐Zvuloni et al, 2022; Wheater et al, 2007), despite the critical importance of the water cycle in these regions. This is the case for the Silala River system, which also has many data gaps due to the remote location of the basin and its extreme environmental conditions.…”

The Contribution of Desert-Dwelling Bats to Pest Control in Hyper-Arid Date Agriculture

“…This gave a boost to biodiversity, including a variety of night-active insects, which are the food source for desert-dwelling insectivorous bats. However, the hydrology of the area has changed over recent decades due to development [66,67], and these flood plains have partially disappeared. Hence, date plantations and other agricultural crops provide alternative habitats for desert bats in lieu of lost natural foraging grounds.…”

Clay minerals in soils and sediment as tracers of provenance: The case study of the N'fis watershed, Morocco

“…Our current understanding of erosion rates in semi‐arid to arid settings owing to overland flow and gully erosion is still limited, despite significant advances in recent years (Armoza‐Zvuloni et al, 2022; Diani et al, 2023; Mor‐Mussery & Laronne, 2020). One of the main challenges in evaluating erosion rates in these regions is the variability of the landscape and the complexity of the erosion processes (de la Torre‐Robles et al, 2023; García‐Ruiz et al, 2013; Gourfi et al, 2020).…”