Fluvial geomorphology<subtitle>Monitoring stream systems in response to a changing environment</subtitle>

An advanced signal processing technique for deriving grain size information of bedload transport from impact plate vibration measurements

“…A significant fraction of the mass transported by running water consists of bedload resulting from channel disturbances (e.g. erosion, flooding, sedimentation) that may affect the stability of entire river networks, from mountain systems to low-altitude streams (Lord et al, 2009). Material accumulation can, for instance, cause damages to weirs, barrages or sluices (Ergenzinger and Schmidt, 1993;Badoux et al, 2014).…”

Data-driven framework for forecasting sedimentation at culverts

“…Conceptually, the processes associated with culvert sedimentation can be grouped into three major categories as illustrated in Figure 2.1: (1) soil detachment (i.e., erosion, sediment supply, and sediment production), (2) sediment transport (overland and in-stream), and (3) sediment deposition (settling at culvert structure and stabilization due to vegetation growth). This grouping tracks the sediment dynamics in the watershed river network continuum as depicted in Figure 2.2, whereby the sedimentation sources (in drainage basins), transport pathways (through watersheds and stream network), and receptors (at basin outlets or downstream culverts) are all connected in an end-to-end system Schumm, 1977;Lord et al, 2009). (Lord et al, 2009;Schumm, 1977) Each stage of culvert sedimentation entails a number of physical processes that are independently reviewed in the Subsections 2.1.2 to 2.1.4.…”

“…This grouping tracks the sediment dynamics in the watershed river network continuum as depicted in Figure 2.2, whereby the sedimentation sources (in drainage basins), transport pathways (through watersheds and stream network), and receptors (at basin outlets or downstream culverts) are all connected in an end-to-end system Schumm, 1977;Lord et al, 2009). (Lord et al, 2009;Schumm, 1977) Each stage of culvert sedimentation entails a number of physical processes that are independently reviewed in the Subsections 2.1.2 to 2.1.4. Along with their review, the relevant contributing factors (environmental and structural) are identified for each sedimentation stage.…”

“…The main goal of this study is to develop a generalized data-driven framework that combines the machine learning techniques with information visualizations to explore the complex environmental processes of culvert sedimentation. The framework is then embedded into a web-based geospatial platform, labelled "IowaDOT Culverts" aimed at disseminating data-driven insights acquired through this research (e.g., culvert sedimentation potential vs. its key drivers) as well as supporting routine culvert Table 2.3 Independent variables involved in the local accumulation of sediment at culverts....... 29 Table 2.4 Comprehensive review of the erosion and sediment transport simulation models by Table 2.5 Comprehensive review of sediment transport simulation models by Papanicolaou et al (2008) Table 2.8 Summary of environmental variables that may affect fluvial processes based on information compiled from Allen (2004), Gregory and Walling (1987), and Lord et al (2009).. 46 Table 5.1 Independent variables and spatial extents identified through the feature selection ..... 148 Table 5.2 Ranking of the independent variables based on feature selection analysis .................. 151 Table 5.3 Comparison between the culvert sedimentation potential and soil erosion potential estimated by RUSLE and WEPP .. (Lord et al, 2009;Schumm, 1977).............. 15 Kellerhals et al, 1976) While culverts are commonly sized to accommodate specific return period flows (i.e., 25, 50, or 100 years) depending on the structure type, there is evidence that culvert failures are rarely related to the exceedance of some level of flood flow . Instead, accumulations of debris and sediment at the culvert inlet that partially block the culverts are more often the underlying cause of the failures.…”

“…However, certain human activities (e.g., stream channelization) that involve straightening of the natural course of a channel, can considerably jeopardize channel stability and lead to excessive rates of streambank erosion. Lord et al (2009) suggests that the degrees of in-stream erosion can be indirectly evaluated through vital signs of stream channels (longitudinal profile and planform) which can be monitored by examination of historic aerial photographs and maps (Lord et al, 2009). 5.…”