skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Sediment Transport into the Swinomish Navigation Channel, Puget Sound—Habitat Restoration versus Navigation Maintenance Needs

Abstract

The 11 mile (1.6 km) Swinomish Federal Navigation Channel provides a safe and short passage to fishing and recreational craft in and out of Northern Puget Sound by connecting Skagit and Padilla Bays, US State abbrev., USA. A network of dikes and jetties were constructed through the Swinomish corridor between 1893 and 1936 to improve navigation functionality. Over the years, these river training dikes and jetties designed to minimize sedimentation in the channel have deteriorated, resulting in reduced protection of the channel. The need to repair or modify dikes/jetties for channel maintenance, however, may conflict with salmon habitat restoration goals aimed at improving access, connectivity and brackish water habitat. Several restoration projects have been proposed in the Skagit delta involving breaching, lowering, or removal of dikes. To assess relative merits of the available alternatives, a hydrodynamic model of the Skagit River estuary was developed using the Finite Volume Community Ocean Model (FVCOM). Here, in this paper, we present the refinement and calibration of the model using oceanographic data collected from the years 2006 and 2009 with a focus on the sediment and brackish water transport from the river and Skagit Bay tide flats to the Swinomish Channel. The model wasmore » applied to assess the feasibility of achieving the desired dual outcome of (a) reducing sedimentation and shoaling in the Swinomish Channel and (b) providing a direct migration pathway and improved conveyance of freshwater into the Swinomish Channel. Finally, the potential reduction in shoaling through site-specific structure repairs is evaluated. Similarly, the potential to significantly improve of brackish water habitat through dike breach restoration actions using the McGlinn Causeway project example, along with its impacts on sediment deposition in the Swinomish Navigation Channel, is examined« less

Authors:
 [1];  [1];  [2];  [3];  [3]
  1. Pacific Northwest National Lab. (PNNL), Seattle, WA (United States)
  2. Skagit River System Cooperative, La Conner, WA (United States)
  3. US Army Corps of Engineers, Seattle, WA (United States)
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE; US Department of the Navy, Office of Naval Research (ONR)
OSTI Identifier:
1353322
Report Number(s):
PNNL-SA-125518
Journal ID: ISSN 2077-1312; 400403209
Grant/Contract Number:
AC05-76RL01830; N00014-08-1-0846
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Marine Science and Engineering
Additional Journal Information:
Journal Volume: 5; Journal Issue: 2; Journal ID: ISSN 2077-1312
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; hydrodynamics; sediment transport; nearshore restoration; dredging; dike alteration; FVCOM; Puget Sound; Salish Sea

Citation Formats

Khangaonkar, Tarang, Nugraha, Adi, Hinton, Steve, Michalsen, David, and Brown, Scott. Sediment Transport into the Swinomish Navigation Channel, Puget Sound—Habitat Restoration versus Navigation Maintenance Needs. United States: N. p., 2017. Web. doi:10.3390/jmse5020019.
Khangaonkar, Tarang, Nugraha, Adi, Hinton, Steve, Michalsen, David, & Brown, Scott. Sediment Transport into the Swinomish Navigation Channel, Puget Sound—Habitat Restoration versus Navigation Maintenance Needs. United States. doi:10.3390/jmse5020019.
Khangaonkar, Tarang, Nugraha, Adi, Hinton, Steve, Michalsen, David, and Brown, Scott. Fri . "Sediment Transport into the Swinomish Navigation Channel, Puget Sound—Habitat Restoration versus Navigation Maintenance Needs". United States. doi:10.3390/jmse5020019. https://www.osti.gov/servlets/purl/1353322.
@article{osti_1353322,
title = {Sediment Transport into the Swinomish Navigation Channel, Puget Sound—Habitat Restoration versus Navigation Maintenance Needs},
author = {Khangaonkar, Tarang and Nugraha, Adi and Hinton, Steve and Michalsen, David and Brown, Scott},
abstractNote = {The 11 mile (1.6 km) Swinomish Federal Navigation Channel provides a safe and short passage to fishing and recreational craft in and out of Northern Puget Sound by connecting Skagit and Padilla Bays, US State abbrev., USA. A network of dikes and jetties were constructed through the Swinomish corridor between 1893 and 1936 to improve navigation functionality. Over the years, these river training dikes and jetties designed to minimize sedimentation in the channel have deteriorated, resulting in reduced protection of the channel. The need to repair or modify dikes/jetties for channel maintenance, however, may conflict with salmon habitat restoration goals aimed at improving access, connectivity and brackish water habitat. Several restoration projects have been proposed in the Skagit delta involving breaching, lowering, or removal of dikes. To assess relative merits of the available alternatives, a hydrodynamic model of the Skagit River estuary was developed using the Finite Volume Community Ocean Model (FVCOM). Here, in this paper, we present the refinement and calibration of the model using oceanographic data collected from the years 2006 and 2009 with a focus on the sediment and brackish water transport from the river and Skagit Bay tide flats to the Swinomish Channel. The model was applied to assess the feasibility of achieving the desired dual outcome of (a) reducing sedimentation and shoaling in the Swinomish Channel and (b) providing a direct migration pathway and improved conveyance of freshwater into the Swinomish Channel. Finally, the potential reduction in shoaling through site-specific structure repairs is evaluated. Similarly, the potential to significantly improve of brackish water habitat through dike breach restoration actions using the McGlinn Causeway project example, along with its impacts on sediment deposition in the Swinomish Navigation Channel, is examined},
doi = {10.3390/jmse5020019},
journal = {Journal of Marine Science and Engineering},
number = 2,
volume = 5,
place = {United States},
year = {Fri Apr 21 00:00:00 EDT 2017},
month = {Fri Apr 21 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Save / Share:
  • Estuarine and coastal hydrodynamic processes are sometimes neglected in the design and planning of nearshore restoration actions. Despite best intentions, efforts to restore nearshore habitats can result in poor outcomes if circulation and transport which also affect freshwater-saltwater interactions are not properly addressed. Limitations due to current land use can lead to selection of sub-optimal restoration alternatives that may result in undesirable consequences, such as flooding, deterioration of water quality, and erosion, requiring immediate remedies and costly repairs. Uncertainty with achieving restoration goals, such as recovery of tidal exchange, supply of sediment and nutrients, and establishment of fish migration pathways,more » may be minimized by using numerical models designed for application to the nearshore environment. A high resolution circulation and transport model of the Puget Sound, in the state of Washington, was developed to assist with nearshore habitat restoration design and analysis, and to answer the question “can we achieve beneficial restoration outcomes at small local scale, as well as at a large estuary-wide scale?” The Puget Sound model is based on an unstructured grid framework to define the complex Puget Sound shoreline using a finite volume coastal ocean model (FVCOM). The capability of the model for simulating the important nearshore processes, such as circulation in complex multiple tidal channels, wetting and drying of tide flats, and water quality and sediment transport as part of restoration feasibility, are illustrated through examples of restoration projects in Puget Sound.« less
  • Concentrations and vertical fluxes of total carbon, aliphatic hydrocarbons, and polycyclic aromatic hydrocarbons (PAH) were determined in suspended matter and the underlying sediments in the central main basin of Puget Sound, Washington. Suspended matter was collected seasonally at four depths in the water column using sequential sampling traps. The flux of PAH through the 50- and 100-m horizons accounted for 84% of the PAH accumulating in the underlying surface sediments. The concentration of PAH in the suspended matter from these traps, however, was 3 times greater than the concentration of PAH in the surficial bottom sediments. Laterally transported suspended mattermore » in the bottom boundary layer is apparently diluting the PAH during sedimentation. The flux of aliphatic hydrocarbons to the sediments was greater than the accumulation rate in the sediments, indicating an alteration of these hydrocarbons within the water column or differential particle transport. The vertical distributions of hydrocarbons in the bottom sediments showed concentration increases parelleling the urbanization of the Puget Sound basin. 30 references.« less
  • A quantitative description of the processes of sediment transport and deposition is developed for one large estuary (Long Island Sound) and the results are put into a form that will ease comparision with other estuaries.
  • Twenty eight bacterial and Br transport experiments were performed in the field to determine the effects of physical and chemical heterogeneity of the aquifer sediment. The experiments were performed using groundwater from two field locations to examine the effects of groundwater chemistry on transport. Groundwater was extracted from multilevel samplers and pumped through 7 cm long columns of intact sediment or re-packed sieved and coated or uncoated sediment from the underlying aquifer. Two bacterial strains, Comamonas sp. DA001 and Paenibacillus polymyxa FER-02, were injected along with Br into the influent end of the columns to examine the effect of cellmore » morphology and surface properties on bacterial transport. The effect of column sediment grain size and mineral coatings coupled with groundwater geochemistry were also delineated. Significant irreversible attachment of DA001 was observed in the Fe oxyhydroxide coated columns, but only in the sub-oxic groundwater where the concentrations of dissolved organic carbon (DOC) were ca. 1 ppm. In the oxic groundwater where DOC was ca. 8 ppm, little attachment of DA001 to the Fe oxyhydroxide coated columns was observed. This indicates that DOC can significantly reduce bacterial attachment due electrostatic interactions. The larger and more negatively charged FER-02 displayed increasing attachment with decreasing grain size regardless of DOC concentration, and modeling of FER-02 attachment revealed that the presence of Fe and Al coatings on the sediment also promoted attachment. Finally, the presence of Al coatings and Al containing minerals appeared to significantly retard the Br tracer regardless of the concentration of DOC. These findings suggest that DOC in shallow oxic groundwater aquifers can significantly enhance the transport of bacteria by reducing attachment to Fe, Mn and Al oxyhydroxides. This effect is profound for weakly charged, hydrophilic bacteria and may contribute to differences in observations between laboratory experiments verses field-scale investigations particularly if the groundwater pH remains circum-neutral and Fe oxyhydroxide phases exist. These observations validate the novel approach taken in the experiments outlined here of performing laboratory-scale experiments on site to facilitate the use of fresh groundwater and thus be more representative of in situ groundwater conditions.« less
  • The authors construct mathematical and experimental flow models to describe the hydrodynamic behavior of sediments eroding into hydroelectric plant waterways for purposes of arriving at sediment reclamation scenarios as well as optimizing waterway design parameters for the minimization of erosion. The models simulate both straight and curved waterways and also allow the determination of the cross-sectional design.