Drainage reversal toward cliffs induced by lateral lithologic differences

Abstract

Drainage reversals, an end-member case of drainage reorganization, often occur toward cliffs. Reversals are commonly identified by the presence of barbed tributaries, with a junction angle >90°, that preserve the antecedent drainage geometry. The processes that form reversed drainages are largely unknown. Particularly, barbed tributaries cannot form through a spatially uniform migration of the cliff and drainage divide, which would be expected to erase the antecedent drainage pattern, and tectonic tilting toward the cliff that could reverse the flow direction is inconsistent with geodynamic models of large-scale escarpment, where many reversals are documented. Here, we propose a new mechanism for drainage reversal, where the slope imbalance across a cliff, together with the high erodibility of sediments that fill cliff-truncated valleys, result in faster divide migration along valleys compared to interfluves. We demonstrate this mechanism along channels that drain toward the escarpment of the Arava Valley in Israel. Reversal is established by observations of barbed tributaries and opposite-grading terraces. We show that drainage reversal occurs when erodible valley fill exists, and that the reversal extent correlates with the thickness of this fill, in agreement with the predictions of the proposed mechanism. This new reversal mechanism demonstrates that valley fill could play an acute role in fluvial reorganization processes, and that reversals could occur independently of tectonic tilting.

Topographic controls on divide migration, stream capture, and diversification in riverine life

“…Uniform erodibility in space and time within a trial is another limitation of this research. Spatiotemporal variation in erodibility can lead to drainage reorganisation where reorganisation may not have occurred without erodibility variation (Forte et al, 2016;Gallen, 2018;Harel et al, 2019). Existing Landlab capabilities offer opportunities to begin addressing some limitations in our model, including simultaneously transporting fluvial sediment and eroding bedrock (Shobe et al, 2017), emplacing lithologic heterogeneity in the model grid (Barnhart et al, 2018), and identifying areas with elevated probability of landsliding (Strauch et al, 2018).…”

“…1; Bishop, 1995). Climatically and tectonically induced changes to base level, water flow direction, and erosional processes can alter topographic structure and reorganise drainages in settings such as internally draining fault-bounded basins (D'Agostino et al, 2001), precipitation gradients (Bonnet, 2009), transient passive margins (Prince et al, 2011;Moodie et al, 2018), intercontinental strike-slip faults (Guerit et al, 2016), and lateral variations in lithologic erodibility (Gallen, 2018;Harel et al, 2019). Yet little attention has been paid to the impact of drainage reorganisation on riverine biota despite the longstanding recognition of their interactions (Bishop, 1995;Albert et al, 2018).…”

The rate and extent of wind-gap migration regulated by tributary confluences and avulsions

“…A distinctly different dynamic is expected to emerge when a drainage divide forms a deep saddle within a valley (a wind gap; e.g., Bishop, 1995). In such settings, the wind gap is lower than the ridges that bound the valley, and thus the morphology of the bounding ridgelines and the tributaries that drain them into the valley can be largely preserved as the wind gap migrates along the valley (e.g., Harel et al, 2019) (Fig. 1c-d).…”

Late Quaternary drainage reorganization assisted by surface faulting: The example of the Katrol Hill Fault zone, Kachchh, western India

“…An increasing number of studies in river basins around the world reveal show large‐scale landscape changes and drainage reorganization (Almeida‐Filho & Miranda, 2007; de Fátima Rossetti et al, 2005; Franzinelli & Igreja, 2002; Silva et al, 2007), for example, the Amazon River basin (Authemayou et al, 2018; Babault et al, 2012; Hayakawa et al, 2010; Mantelli et al, 2009; Rossetti & Góes, 2008); the Yarlung Zangbo–Brahmaputra River system (Bracciali et al, 2015; Ghosh et al, 2015; Jiang et al, 2016; Korup & Montgomery, 2008; Lahiri & Sinha, 2012; Lang & Huntington, 2014; Schmidt et al, 2015; Zeitler et al, 2001; Zhang et al, 2012) and the Three River watershed (Whipple et al, 2017; Yang et al, 2016). Plate tectonics and the evolution of passive margins have been identified as critical for understanding the long‐term landscape evolution and drainage history (Bishop, 1995, 1998; Harel et al, 2019; Summerfield, 1985, 1991), along with them being the prime cause of macroscale “drainage rearrangement” phenomenon (Bishop, 1986, 1988; Driscoll & Karner, 1994; Oilier, 1982; van de Graaff et al, 1977). In general, the phenomenon of drainage capture is obscured because of the low frequency of its occurrence and fluvial terrace deposits (Clift et al, 2006; Fan & B Wu, 2010; Fan et al, 2018; Val et al, 2014; Wei et al, 2016; Zhou, 2010).…”

“…Some studies have elaborated the impact of river diversions on the upstream drainage in medium‐sized catchments (Authemayou et al, 2018; Giletycz et al, 2015; Stokes et al, 2002). Studies of drainage reorganizations in smaller scale drainage basins and sub‐basins are generally rare (Harel et al, 2019).…”