Sediment Transport Potential in a Hydraulically Connected River and Floodplain‐Channel System

Abstract

Floodplains are intermittently flooded complex geomorphic features with positive and negative relief (Lewin & Ashworth, 2014). Negative relief consists of meso-and macro-scale elements that include accessory through-channels, tributary channels, channel margin slackwater zones, bar-shelter backwaters, contiguous channel remnants, tie channels, internal drainage channel networks, and large-scale flood basins occluded by channel-belt aggradation (Lewin & Ashworth, 2014). This negative relief is present on both braided (

Incorporating flowpaths as an explicit measure of river-floodplain connectivity to improve estimates of floodplain sediment deposition

“…The RMSE and MAE for simulated depth-average velocities with USGS measure-ments was 0.20 m/s and 0.13 m/s, respectively (n=24). These velocity errors were comparable to the hydrodynamic model validation errors (RMSE of 0.27 m/s, MAE of 0.21m/s) reported by Czuba et al (2019) and Sumaiya et al (2021). Our reported calibration and validation statistics only include the flows that inundate the floodplain (≥ 28 m 3 /s, RI: 1-year) because our analysis is focused on only floodplain-inundating flows.…”

“…2a). Model error compared to the USGS rating curve was close to the variability between the USGS measurements and the rating curve (Czuba et al, 2019;Sumaiya et al, 2021). The RMSE and MAE of the model simulated depth-averaged velocity to the USGS measurements of channel velocity was 0.25 m/s and 0.21 m/s, respectively (n=21; ≥ 28 m 3 /s, RI: 1-year) (Fig.…”

“…Lidar data with its ability to represent floodplain topography at meter-scale resolution (Hilldale and Raff, 2008) can reveal the complex nature of floodplain hydromorphodynamic processes (Rak et al, 2016;David et al, 2017David et al, , 2018Kupfer et al, 2015;Thayer and Ashmore, 2016;Xu et al, 2020). Furthermore, incorporating high-resolution topographic data into numerical models, along with field measurements, can better quantify floodplain processes in detail (Czuba et al, 2019;Maaß and Schüttrumpf, 2019;Sumaiya et al, 2021;van der Steeg et al, 2023).…”

Floodplain Connecting Channels as Critical Paths for Hydrological Connectivity of Deltaic River Networks

“…Presumably, the reclamation of the floodplain due to urbanization in the delta could potentially result in narrowing connecting channels or loss of connecting channels between the branches (Figure 10). On the one hand, the shrinkage of connecting channels could affect the flow and sediment exchanges between rivers and their floodplains (Sumaiya et al., 2021; Tull et al., 2022). On the other hand, this could also lead to a decreasing modulating capacity of water partitioning at the upstream bifurcation and hence the hydrological connectivity of the river network.…”

“…The bifurcation‐connecting channel unit consists of two branches splitting at an upstream bifurcation and a connecting channel further splitting from one of the branches and joining the other branch (see Figure 1). These floodplain connecting channels, on the one hand, are important conduits linking rivers and floodplains and sustaining fluvial ecosystems (Abrial et al., 2019; Sumaiya et al., 2021; Trigg et al., 2012; Tull et al., 2022). On the other hand, the connecting channel between the two branches can also act as a downstream control affecting the hydrodynamics in the two branches, such as their slope difference.…”