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Weaverville, CA, United States

Viparelli E.,University of Illinois at Urbana - Champaign | Viparelli E.,University of Naples Federico II | Gaeuman D.,Trinity River Restoration Program | Wilcock P.,Johns Hopkins University | Parker G.,University of Illinois at Urbana - Champaign
Water Resources Research

Major changes in the morphology of the Trinity River in California, such as narrowing of the cross section and sedimentation of fine sediment in pools, occurred after the closure of a system of dams. These changes caused a dramatic reduction in the salmonid population and a resulting decline of the fishery. Gravel augmentation, regulated flood releases, and mechanical channel rehabilitation are currently being implemented to help restore the aquatic habitat of the river. The present paper describes a tool, named the Spawning Gravel Refresher, for designing and predicting the effects of gravel augmentation in gravel bed rivers. The tool assumes an imposed, cycled hydrograph. The model is calibrated and applied to the regulated reach of the Trinity River in four steps: (1) zeroing runs to reproduce conditions of mobile bed equilibrium as best can be estimated for the predam Trinity River, (2) runs to compare the predictions with the results of previous studies, (3) runs at an engineering time scale to reproduce the effects of the dams, and (4) runs to design gravel augmentation schemes. In the fourth group of runs, the combined effects of engineered flood flow releases and gravel augmentation are predicted. At an engineering time scale, the model indicates that the fraction of fine sediment in the surface layer and in the topmost part of the substrate should decrease when subjected to these two restoration measures, with a consequent improvement of the quality of the spawning gravel. Copyright 2011 by the American Geophysical Union. Source

Gaeuman D.,Trinity River Restoration Program | Bunte K.,Colorado State University
Water Resources Research

Fluvial sediment loads are frequently calculated with rating curves fit to measured sediment transport rates. Rating curves are often treated as statistical representations in which the fitted parameters have little or no physical meaning. Such models, however, may produce large errors when extrapolation is needed, and they provide no insight into the sediment transport process. It is shown that log-linear least squares, the usual method for fitting rating curves, does not generally produce physically meaningful parameter values. In addition, it cannot accommodate data that include zero-transport samples. Alternative fitting methods based nonlinear least squares and on maximum likelihood parameter estimation are described and evaluated. The maximum likelihood approach is shown to fit synthetic data better than linear or nonlinear least squares, and to perform well with data that include zero-transport samples. In contrast, nonlinear least squares methods produce large errors in the parameter estimates when zero-transport samples are present or when the variance structure of the data is incorrectly specified. Analyses with fractional bedload data from a mountain stream suggest that bedload transport rates are gamma distributed, that the arrivals of bedload particles in a sampler conform to a Poisson distribution, and that the variance of nonzero samples can be expressed as a power function of the mean. Preliminary physical interpretations of variations in the rating curve parameters fit to fractional bedload data with the maximum likelihood method are proposed, and their relation to some previous interpretations of rating curve parameters are briefly discussed. © 2014. American Geophysical Union. All Rights Reserved. Source

Chase R.,Bureau of Reclamation | Hemphill N.,Trinity River Restoration Program | Beeman J.,U.S. Geological Survey | Juhnke S.,U.S. Geological Survey | Hannon J.,Bureau of Reclamation
Environmental Biology of Fishes

Coho salmon (Oncorhynchus kisutch) of the Southern Oregon/Northern California Coast (SONCC) Evolutionarily Significant Unit (ESU) is federally listed as a threatened species. The Trinity River Restoration Program (TRRP) is rehabilitating the Trinity River to restore coho salmon (coho) and other salmonid populations. In order to evaluate the program's actions, several studies of movements and behavior of coho in the Trinity River were conducted from 2006 to 2009, including snorkel surveys and mark-recapture techniques based on Passive Integrated Transponder (PIT) tags, elastomer tags, and radio transmitters. Catch, recapture, and condition of natural sub-yearlings, along with site fidelity and emigration of hatchery-reared yearlings in rehabilitated and reference habitats, were studied. Location was important because coho were absent from the lower controlled and rehabilitated sites most of the time. However, rehabilitation did not have a significant effect on natural coho salmon at the site level. Apparent survival of radio-tagged, hatchery-reared yearling coho released downstream from Lewiston Dam was much lower in the first 10 km downstream from the release site than in other areas between Lewiston Dam and the Klamath River estuary. Estimated survival of yearling hatchery coho salmon per 100 km down to Blake's Riffle was estimated at 64 % over the distance of the 239 km study area. Migration primarily occurred at night in the upper Trinity River; however, as yearlings moved through the lower Trinity River towards the Klamath River, estuary nocturnal migration became less. Apparent survival was generally lowest in areas upstream from the North Fork of the Trinity River. © 2012 Springer Science+Business Media B.V. (outside the USA). Source

Ock G.,University of California at Berkeley | Ock G.,Hanyang University | Gaeuman D.,Trinity River Restoration Program | McSloy J.,Trinity River Restoration Program | Kondolf G.M.,University of California at Berkeley
Ecological Engineering

Gravel augmentation has been increasingly used in sediment-limited systems in regulated channels as a means of creating morphological changes that beneficially affect the functioning of downstream ecosystems. Despite this trend, there have been few empirical studies to quantify these effects in relation to the morphology of gravel bars, especially in terms of riverine material exchanges such as heat and organic matter. We conducted field-based hydro-geomorphological observation of different mechanisms of gravel bar restoration in the downstream of Trinity Dam, California: a medial and a point bar deposited fluvially during high-flow gravel injection, an additional point bar created by direct placement of gravel, and an island created by side channel excavation. We measured water temperature, suspended particulate organic matter (S-POM) concentration, hydraulic gradients and shallow water width under base flow conditions along the perimeter of the gravel features. We then assessed water temperature modulation derived from hyporheic exchanges and S-POM retention of the gravel features, comparing the functions of the dynamically-constructed medial and point bars to those of the mechanically-constructed island and point bar. Diurnal water temperature fluctuations showed a notable thermal heterogeneity including cooling (1.5-3.1. °C) during summer peak temperatures, buffering in amplitude (1.2-4.0. °C) and lagging in phase (0.3-14.5. h), especially in the bar-tails and alcoves of the gravel bars. All of the gravel features reduced S-POM concentration at baseflow, showing the highest retention efficiency in the medial bar. In addition, the fluvially formed the medial and point bars had higher hydraulic gradients and wider shallow waters than the constructed features. Our results indicate that gravel bar restoration can increase hyporheic exchange and S-POM retention by increasing hydraulic gradients at baseflow, refreshing bed materials to enhance substrate permeability, and elongating the wetted boundary length in shallow waters. Our study results suggest that mechanically created in-channel geomorphic features combined with coarse sediment augmentation can increase channel complexity, driving hyporheic flows and increasing S-POM retention, thus ultimately resulting in thermal heterogeneity and food availability along gravel bed channels. © 2015 Elsevier B.V.. Source

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