The evolution of gravel bed channels after dam removal: Case study of the Anaconda and Union City Dam removals

Geomorphology ◽  
2005 ◽  
Vol 71 (1-2) ◽  
pp. 245-262 ◽  
Author(s):  
Laura A.S. Wildman ◽  
James G. MacBroom
Keyword(s):  
Dam Removal ◽  
Gravel Bed ◽  
Dam Removals ◽  
Union City

scholarly journals Watershed Suspended Sediment Supply and Potential Impacts of Dam Removals for an Estuary

2021 ◽  
Author(s):  
David K. Ralston ◽  
Brian Yellen ◽  
Jonathan D. Woodruff
Keyword(s):  
Suspended Sediment ◽  
River Estuary ◽  
Dam Removal ◽  
Hudson River ◽  
Sediment Traps ◽  
Sediment Supply ◽  
Watershed Area ◽  
Natural Lakes ◽  
Sediment Deposits ◽  
Dam Removals

AbstractObservations and modeling are used to assess potential impacts of sediment releases due to dam removals on the Hudson River estuary. Watershed sediment loads are calculated based on sediment-discharge rating curves for gauges covering 80% of the watershed area. The annual average sediment load to the estuary is 1.2 Mt, of which about 0.6 Mt comes from side tributaries. Sediment yield varies inversely with watershed area, with regional trends that are consistent with substrate erodibility. Geophysical and sedimentological surveys in seven subwatersheds of the Lower Hudson were conducted to estimate the mass and composition of sediment trapped behind dams. Impoundments were classified as (1) active sediment traps, (2) run-of-river sites not actively trapping sediment, and (3) dammed natural lakes and spring-fed ponds. Based on this categorization and impoundment attributes from a dam inventory database, the total mass of impounded sediment in the Lower Hudson watershed is estimated as 4.9 ± 1.9 Mt. This represents about 4 years of annual watershed supply, which is small compared with some individual dam removals and is not practically available given current dam removal rates. More than half of dams impound drainage areas less than 1 km2, and play little role in downstream sediment supply. In modeling of a simulated dam removal, suspended sediment in the estuary increases modestly near the source during discharge events, but otherwise effects on suspended sediment are minimal. Fine-grained sediment deposits broadly along the estuary and coarser sediment deposits near the source, with transport distance inversely related to settling velocity.

Total load transport in gravel bed and sand bed rivers case study: Chelichay watershed

2013 ◽  
Vol 28 (1) ◽  
pp. 46-57 ◽  
Author(s):  
Arman HADDADCHI ◽  
Mohammad H. OMID ◽  
Amir A. SDEHGHANI
Keyword(s):  
Total Load ◽  
Gravel Bed ◽  
Load Transport

scholarly journals Dam Removal Information Portal (DRIP)—A map-based resource linking scientific studies and associated geospatial information about dam removals

2016 ◽  
Author(s):  
Jeffrey J. Duda ◽  
Daniel J. Wieferich ◽  
R. Sky Bristol ◽  
J. Ryan Bellmore ◽  
Vivian B. Hutchison ◽  
...  
Keyword(s):  
Dam Removal ◽  
Geospatial Information ◽  
Information Portal ◽  
Dam Removals

scholarly journals A 2D hydrodynamic-sedimentological model for gravel bed rivers. Part II, Case study: the Brenta River in Italy

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
Gabriel Kaless ◽  
Johnny Moretto ◽  
Fabio Delai ◽  
Luca Mao ◽  
Mario A. Lenzi
Keyword(s):  
Low Frequency ◽  
Channel Changes ◽  
Gravel Bed ◽  
Digital Terrain ◽  
Terrain Models ◽  
Extensive Field ◽  
Subsurface Material ◽  
Sediment Flow ◽  
Imaging Detection

A 2D depth average model has been used to simulate water and sediment flow in the Brenta River so as to interpret channel changes and to assess model predictive capabilities. The Brenta River is a gravel bed river located in Northern Italy. The study reach is 1400 long and has a mean slope of 0.0056. High resolution digital terrain models has been produced combining laser imaging detection and ranging data with colour bathymetry techniques. Extensive field sedimentological surveys have been also carried out for surface and subsurface material. The data were loaded in the model and the passage of a high intense flood (R.I. > 9 years) was simulated. The model was run under the hypothesis of a substantial equilibrium between sediment input and transport capacity. In this way, the model results were considered as a reference condition, and the potential trend of the reach was assessed. Low-frequency floods (R.I. » 1.5 years) are expected to produce negligible changes in the channel while high floods may focalize erosion on banks instead than on channel bed. Furthermore, the model predicts well the location of erosion and siltation areas and the results promote its application to other reaches of the Brenta River in order to assess their stability and medium-term evolution.

scholarly journals Geomorphic Evolution of a Gravel‐Bed River Under Sediment‐Starved Versus Sediment‐Rich Conditions: River Response to the World's Largest Dam Removal

2018 ◽  
Vol 123 (12) ◽  
pp. 3338-3369 ◽  
Author(s):  
A. E. East ◽  
J. B. Logan ◽  
M. C. Mastin ◽  
A. C. Ritchie ◽  
J. A. Bountry ◽  
...  
Keyword(s):  
Dam Removal ◽  
Geomorphic Evolution ◽  
Gravel Bed ◽  
Gravel Bed River

scholarly journals Dam Removal Effects on Benthic Macroinvertebrate Dynamics: A New England Stream Case Study (Connecticut, USA)

2019 ◽  
Vol 11 (10) ◽  
pp. 2875 ◽  
Author(s):  
Helen M. Poulos ◽  
Kate E. Miller ◽  
Ross Heinemann ◽  
Michelle L. Kraczkowski ◽  
Adam W. Whelchel ◽  
...  
Keyword(s):  
Community Structure ◽  
New England ◽  
Stream Restoration ◽  
Mixed Model ◽  
Dam Removal ◽  
Benthic Macroinvertebrate ◽  
Mixed Model Analysis ◽  
Removal Time ◽  
Small Streams

Dam removal is an increasingly common stream restoration tool. Yet, removing dams from small streams also represents a major disturbance to rivers that can have varied impacts on environmental conditions and aquatic biota. We examined the effects of dam removal on the structure, function, and composition of benthic macroinvertebrate (BMI) communities in a temperate New England stream. We examined the effects of dam removal over the dam removal time-series using linear mixed effects models, autoregressive models, non-metric multidimensional scaling, and indicator and similarity analyses. The results indicated that the dam removal stimulated major shifts in BMI community structure and composition above and below the dam, and that the BMI communities are becoming more similar over time. The mixed model analysis revealed that BMI functional groups and diversity were significantly influenced by sample site and several BMI groups also experienced significant interactions between site and dam stage (P < 0.05), while the multivariate analyses revealed that community structure continues to differ among sites, even three years after dam removal. Our findings indicate that stream restoration through dam removal can have site-specific influences on BMI communities, that interactions among BMI taxa are important determinants of the post-dam removal community, and that the post-dam-removal BMI community continues to be in a state of reorganization.

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