Title: Hydrodynamic Zone of Influence Due to a Floating Structure in a Fjordal Estuary—Hood Canal Bridge Impact Assessment

Journal Article · · Journal of Marine Science and Engineering
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  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
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Floating structures such as barges and ships affect near-field hydrodynamics and create a zone of influence (ZOI). Extent of the ZOI is of particular interest due to potential obstruction to and impact on out-migrating juvenile fish. Here, we present an assessment of ZOI from Hood Canal (Floating) Bridge, located within the 110-km-long fjord-like Hood Canal sub-basin in the Salish Sea, Washington. A field data collection program allowed near-field validation of a three-dimensional hydrodynamic model of Hood Canal with the floating bridge section embedded. The results confirm that Hood Canal Bridge, with a draft of 4.6 m covering ~85% of the width of Hood Canal, obstructs the brackish outflow surface layer. This induces increased local mixing near the bridge, causes pooling of water (up-current) during ebb and flood, and results in shadow/sheltering of water (down-current). The change in ambient currents, salinity, and temperature is highest at the bridge location and reduces to background levels with distance from the bridge. The ZOI extends ~20 m below the surface and varies from 2–3 km for currents, from 2–4 km for salinity, and from 2–5 km for temperature before the deviations with the bridge drop to <10% relative to simulated background conditions without the bridge present.

Research Organization:
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Sponsoring Organization:
State of Washington; USDOE
Grant/Contract Number:
AC05-76RL01830
OSTI ID:
1633404
Report Number(s):
PNNL-SA-146774
Journal Information:
Journal of Marine Science and Engineering, Journal Name: Journal of Marine Science and Engineering Journal Issue: 4 Vol. 6; ISSN 2077-1312
Publisher:
MDPICopyright Statement
Country of Publication:
United States
Language:
English

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Development of a Kelp-Type Structure Module in a Coastal Ocean Model to Assess the Hydrodynamic Impact of Seawater Uranium Extraction Technology journal February 2014

Cited By (1)

Detailed Hydrodynamic Feasibility Assessment for Leque Island and Zis a Ba Restoration Projects journal November 2018

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Related Subjects

54 ENVIRONMENTAL SCIENCES
Finite-Volume Community Ocean Model (FVCOM)
Hood Canal
Salish Sea
Salish Sea model
anthropogenic impact
circulation
floating bridge
hydrodynamics
zone of influence