Installation of Impact Plates to Continuously Measure Bed Load: Elwha River, Washington, USA

Hilldale, Robert C.; Carpenter, Wayne O.; Goodwiller, Bradley T.; Chambers, James P.; Randle, Timothy J.

doi:10.1061/(asce)hy.1943-7900.0000975

Cited by 30 publications

(25 citation statements)

References 22 publications

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“…Averaging measurements of bed load transport over increasing time periods has been shown to clearly increase the correlation between a measure of transport and a measure of water discharge (Downs et al, ; Lenzi et al, ; Recking et al, ; Rickenmann, ; Rickenmann & McArdell, ). This study demonstrated a substantial increase in the correlation coefficient R between log( Q b ) and log( Q ) for aggregation times of about 1–2 h (Figure ), which integrates over typical short term fluctuations of 15–35 min of bed load transport rates in natural gravel bed streams (Habersack et al, ; Hilldale, ; Reid & Frostick, ; see also section 4.2). Two different empirical bed load transport relations (equations (10) and (14)) were developed here based on daily mean values.…”

Section: Discussionsupporting

confidence: 52%

“…The temporal variability of bed load transport at a time scale of less than 1 h was assessed for the Drau River in Austria by Habersack et al () and for the Elwha River in U.S. by Hilldale (). In both studies, SPG measurements with a 1 min recording interval of geophone impulses were used and a periodicity of bed load peaks ranging from 15 to 35 min was determined, based on moving 5 min average values.…”

Section: Discussionmentioning

confidence: 99%

“…For the Ruetz, there is a superposition of more frequent peaks with a periodicity of about 5 min. Fluctuations with a periodicity of 14–35 min were found both in natural streams (Habersack et al, ; Hilldale, ; Reid & Frostick, ) and in flumes (Kuhnle & Southard, , Strom et al, ) under a variety of hydraulic conditions and sediment supply. Possible reasons for such fluctuations may be moving bed load sheets or the formation and destruction of gravel clusters (Hilldale, ; Kuhnle & Southard, ).…”

Section: Discussionmentioning

confidence: 99%

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Variability of Bed Load Transport During Six Summers of Continuous Measurements in Two Austrian Mountain Streams (Fischbach and Ruetz)

Rickenmann

2018

Water Resources Research

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Previous measurements of bed load transport in gravel bed streams revealed a large temporal and spatial variability of bed load transport rates. Using an impact plate geophone system, continuous bed load transport measurements were made during 6 years in two mountain streams in Austria. The two streams have a snow‐melt and glacier‐melt dominated hydrologic regime resulting in frequent transport activity during the summer half year. Periods of days to weeks were identified which are associated with approximately constant Shields values that indicate quasi‐stable bed conditions. Between these stable periods, the position of the bed load transport function varied while its steepness remained approximately constant. For integration time scales of several hours to 1 day, the fluctuations in bed load transport decreased and the correlation between bed load transport and water discharge increased. For integration times of about 70–100 days, bed load transport is determined by discharge or shear stress to within a factor of about 2, relative to the 6 year mean level. Bed load texture increased with increasing mean flow strength and mean transport intensity. Weak and predominantly clockwise daily hysteresis of bed load transport was found for the first half of the summer period.

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Section: Discussionsupporting

confidence: 52%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Variability of Bed Load Transport During Six Summers of Continuous Measurements in Two Austrian Mountain Streams (Fischbach and Ruetz)

Rickenmann

2018

Water Resources Research

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“…Bedload sediment transport was calculated using a combination of steel bedload-impact plates and physical bedload sampling during November, 2012; March, May, and June 2013; and April 2014 at the Diversion Weir gauge 21,61 . These techniques estimated the proportion of bedload in the >16 mm and 2–16 mm size classes, but did not capture bedload transport of particles smaller than 2 mm, which were estimated from a combination of regional and comparative studies in high-sediment load rivers—including other dam removal studies—using constant ratios of measured total bedload to total sediment discharge of 15% for water year 2012 and 25% for later years.…”

Section: Methodsmentioning

confidence: 99%

Morphodynamic evolution following sediment release from the world’s largest dam removal

Ritchie

Warrick

East

et al. 2018

Sci Rep

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105

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Sediment pulses can cause widespread, complex changes to rivers and coastal regions. Quantifying landscape response to sediment-supply changes is a long-standing problem in geomorphology, but the unanticipated nature of most sediment pulses rarely allows for detailed measurement of associated landscape processes and evolution. The intentional removal of two large dams on the Elwha River (Washington, USA) exposed ~30 Mt of impounded sediment to fluvial erosion, presenting a unique opportunity to quantify source-to-sink river and coastal responses to a massive sediment-source perturbation. Here we evaluate geomorphic evolution during and after the sediment pulse, presenting a 5-year sediment budget and morphodynamic analysis of the Elwha River and its delta. Approximately 65% of the sediment was eroded, of which only ~10% was deposited in the fluvial system. This restored fluvial supply of sand, gravel, and wood substantially changed the channel morphology. The remaining ~90% of the released sediment was transported to the coast, causing ~60 ha of delta growth. Although metrics of geomorphic change did not follow simple time-coherent paths, many signals peaked 1–2 years after the start of dam removal, indicating combined impulse and step-change disturbance responses.

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“…where S is the cumulative number of impulses on the impact plate(s) over one hour and k b = 1.17 is an 284 empirically derived calibration parameter determined using synchronous bedload samples and impact-285 plate impulses (Hilldale et al, 2014). Integrating the number of impulses per hour allowed the averaging 286 of temporal variations in impulse frequency that we observed with data from the Elwha River.…”

mentioning

confidence: 99%

Large-scale dam removal on the Elwha River, Washington, USA: Fluvial sediment load

et al. 2015

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Installation of Impact Plates to Continuously Measure Bed Load: Elwha River, Washington, USA

Cited by 30 publications

References 22 publications

Variability of Bed Load Transport During Six Summers of Continuous Measurements in Two Austrian Mountain Streams (Fischbach and Ruetz)

Variability of Bed Load Transport During Six Summers of Continuous Measurements in Two Austrian Mountain Streams (Fischbach and Ruetz)

Morphodynamic evolution following sediment release from the world’s largest dam removal

Large-scale dam removal on the Elwha River, Washington, USA: Fluvial sediment load

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