Columbia River estuary overview of physical features and habitats

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Columbia River estuary overview of physical
features and habitats
Colin Levings ISAB

Thanks owing to Jen Burke UW and Chris Hathaway
LCREP for graphics
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What is an estuary? -a semi-enclosed body of
water where freshwater and saltwater mix (common
usage) -the entire portion of a river that is
influenced by ocean tides (Williams et al 2006
for the Columbia River estuary)
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Why should we concerned about physical features
of the estuary ? -interacting with biological
factors (competition, predation) physical factors
influence the distribution, abundance, and
survival of fish. John Ferguson and Don Lyons
will discuss. Examples -temperature influences
growth and food requirements -salinity
influences the smolting process when
salmon migrate from fresh to salt
water -currents and water depth can affect
distribution
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Regional setting for the Columbia River
estuary -water from the largest watershed on the
northeast Pacific coast drains through this
drowned river valley (map from Emmett et al
2000)
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Salinity and tidal influence
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Temperature at Warrendale (from Fuhrer et al
1996)
Flow at The Dalles 1901-1950 and
1980-2003 (from Naik and Jay 2005)
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Why should we be concerned about wetland habitat
in the estuary? Dan Bottom will
discuss. -detritus (complex of decaying
vegetation and microbes) is recognized as a main
source of energy for invertebrates (fish food)
supporting estuarine food webs -vegetation area
can be measured and used as a surrogate for fish
habitat because vegetation is also influenced by
physical factors
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Historical wetlands
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Contemporary wetlands
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Cover and bathymetry by mapping
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Satellite imagery
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Video inventory of shoreline to help
plan restoration
Wetland Loss Grays River
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LCREP will describe restoration activities