Quantifying sediment storage on the floodplains outside levees along the lower Yellow River during the years 1580–1849

Abstract

The lower Yellow River channel was maintained by artificial levees between 1580 and 1849. During this period, 280 levee breaches occurred. To estimate sediment storage on the floodplains outside the levees, a regression model with a decadal time step was developed to calculate the outflow ratio for the years when levee breaching occurred. Uncertainty analysis was used to identify the likely outflow ratio. Key variables of the model include annual water discharge, a proxy for levee conditions, and potential bankfull discharge of the channel before flood season. Uncertainty analysis reveals an outflow ratio of 0.35–0.56. We estimate that during this period, 18.8–30.1% of the total ~312 Gt of sediment load was deposited on the floodplains outside the levees. Human‐accelerated erosion in the Loess Plateau caused a 4‐fold increase in sediment delivery to the lower Yellow River, which could not be accommodated by channel morphodynamic changes. As a result, 21.2–27.5% of the total sediment load was deposited within the levees, creating a super‐elevated channel bed that facilitated an uncommonly high breach outflow ratio. Hence, the factor of a large super‐elevation relative to the mean main channel depth should be considered when designing diversions to restore floodplains. © 2018 John Wiley & Sons, Ltd.

A 2000-year documentary record of levee breaches on the lower Yellow River and their relationship with climate changes and human activities

“…800 km-long super-elevated channel belt that perches above the surrounding floodplain by as much as around 10 m, thereby leading to frequency levee breaches and river avulsions. Although numerical modeling and statistical analyses were conducted (Chen et al, 2015(Chen et al, , 2019, the operational mechanisms and variability of this embankment-siltation-breaching feedback are still not well understood.…”

“…Given the disastrous nature, levee breaching is one of the most hazardous natural events to human livelihood in the Yellow River floodplain during the last 2000 years (Kidder and Liu, 2014; Wu et al, 2019). It is also the trigger event for river avulsion, which played a pivotal role in sediment dispersal and the evolutions of the floodplain landscape (Chen et al, 2019; Nienhuis et al, 2018). A deeper understanding of levee breach frequency and their relationship with climate changes, human activities, and the fluvial landscape evolution requires precise timing on these events.…”

An Integrative Conceptualization of Floodplain Storage

“…Catchment‐scale sediment budget models can be used to predict volumes of floodplain sediment storage (e.g., Malmon et al., 2002; Nicholas et al., 2006), as can regression models based on limited empirical data (e.g., Chen et al., 2019).…”

“…Catchment-scale sediment budget models can be used to predict volumes of floodplain sediment storage (e.g., Malmon et al, 2002;Nicholas et al, 2006), as can regression models based on limited empirical data (e.g., Chen et al, 2019). Marron (1992) summarized several studies that quantified floodplain storage of sediment introduced to perennial rivers in the United States (drainage area range <70 to 5,000 km 2 ) over time periods of 30-300 years as a result of human activities such as mining, agriculture, and timber harvest.…”

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

“…There are a number of methods that have been used to quantify one or more aspects of the floodplain component in a watershed or reach-scale sediment budget. Regression models have been developed to explain the spatial variability of sediment and nutrients (Hopkins et al, 2018) and to estimate the deposited sediment volume on a floodplain (Chen et al, 2019;Noe et al, 2022). Seasonal and annual patterns of floodplain sediment storage have been calculated from the measurement of water level and flow discharge in combination with surface suspended sediment maps from remote sensing (Park, 2020;Park and Latrubesse, 2019).…”