Computing spatially distributed sediment delivery ratios: inferring functional sediment connectivity from repeat high‐resolution digital elevation models. Issue 7 (2nd February 2018)

• Record Type: Journal Article
• Authors: Heckmann, Tobias; Vericat, Damià
• Is Part Of: Earth surface processes and landforms. Volume 43:Issue 7(2018)
• Page Start: 1547
• Page End: 1554
• Publication Date: 2018-02-02
• Subjects: digital elevation models -- sediment connectivity -- sediment delivery ratio; Geomorphology -- Periodicals; 551.4
• DOI: 10.1002/esp.4334
• Languages: English
• ISSNs: 0197-9337

Abstract

Abstract: High‐resolution digital elevation models (DEMs) from repeat LiDAR (light detection and ranging) or SfM (structure from motion) surveys have become an important tool in process geomorphology. The spatial pattern of negative and positive changes of surface elevation on raster DEMs of difference (DoD) can be interpreted in terms of geomorphic processes, and has been used for morphological budgeting. We show how the application of flow routing algorithms and flow accumulation opens new opportunities for the analysis of DoD. By accumulating the values of the DoD along downslope flowpaths delineated on a DEM, these algorithms lend themselves to computing the net balance, i.e. sediment yield (SY), for the contributing area of each cell. Doing the same for the negative subset of the DoD yields a minimum estimate of erosion ( E ) within the contributing area. The division of SY by E yields (a maximum estimate of) the sediment delivery ratio (SDR), that is the proportion of material eroded within the contributing area of each cell that has been exported from that area. The resulting SDR is a spatially distributed measure of functional sediment connectivity. In this letter, we develop the computationally simple approach by means of an example DoD from a lateral moraine section in the Upper Kaunertal Valley, Austrian Central Alps. We also discuss advantages, assumptions and limitations, and outline potential applications to connectivity research using field‐, laboratory‐, and model‐based DoD. Copyright © 2018 John Wiley & Sons, Ltd. Abstract : Application of flow accumulation to digital elevation models of difference is used to compute spatially distributed sediment yield and delivery ratio. Example from airborne LiDAR elevation models spanning six years shows spatial patterns of geomorphic changes and variability of sediment delivery ratio on a lateral moraine section. We argue that this approach can be used to assess functional sediment connectivity and discuss caveats and potential applications in future research.