Controls on Zero‐Order Basin Morphology. Issue 12 (10th December 2018)

• Record Type: Journal Article
• Authors: Grieve, Stuart W. D.; Hales, Tristram C.; Parker, Robert N.; Mudd, Simon M.; Clubb, Fiona J.
• Is Part Of: Journal of geophysical research. Volume 123:Issue 12(2018)
• Page Start: 3269
• Page End: 3291
• Publication Date: 2018-12-10
• Subjects: zero‐order basin -- landslide -- hillslope geomorphology -- landscape evolution modeling -- lidar -- hillslope sediment transport; Geomorphology -- Periodicals; 551.3
• DOI: 10.1029/2017JF004453
• Languages: English
• ISSNs: 2169-9003

Abstract

Abstract : Zero‐order basins are common features of soil‐mantled landscapes, defined as unchanneled basins at the head of a drainage network. Their geometry and volume control how quickly sediment may reaccumulate after landslide evacuation and, more broadly, zero order basins govern the movement of water and sediment from hillslopes to the fluvial network. They also deliver water and sediment to the uppermost portions of the fluvial network. Despite this role as the moderator between hillslope and fluvial processes, little analysis on their morphology has been conducted at the landscape scale. We present a method to identify zero‐order basins in landscapes and subsequently quantify their geometric properties using elliptical Fourier analysis. We deploy this method across the Coweeta Hydrologic Laboratory, USA. Properties such as length, relief, width, and concavity follow distinct probability distributions, which may serve as a basis for testing predictions of future landscape evolution models. Surprisingly, in a landscape with an orographic precipitation gradient and large hillslope to channel relief, we observe no correlation between elevation or spatial location and basin geometry. However, we find that two physiographic units in Coweeta have distinct zero‐order basin morphologies. These are the steep, thin soiled, high‐elevation Nantahala Escarpment and the lower‐gradient, lower‐elevation, thick soiled remainder of the basin. Our results indicate that basin slope and area negatively covary, producing the distinct forms observed between the two physiographic units, which we suggest arise through competition between spatially variable soil creep and stochastic landsliding. Key Points: We can extract zero‐order basins from high‐resolution topographic data Within areas of similar physiography, zero‐order basin size and shape vary widely with a random distribution When there is a dramatic steepening of topography, zero‐order basins appear to be narrower