1. Columbia River estuary – overview of physical features and habitats
Colin Levings
ISAB
Thanks owing to Jen Burke UW and
Chris Hathaway LCREP for graphics

2. 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)

3. 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

4. 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)

5. Salinity and tidal influence

6. Temperature at Warrendale
(from Fuhrer et al 1996)
Flow at The Dalles
and
(from Naik and Jay 2005)

7. 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

8. Historical wetlands

9. Contemporary wetlands

10. Cover and bathymetry by mapping

11. Satellite imagery

12. Video inventory
of shoreline to
help plan
restoration
Wetland Loss – Grays River

13. LCREP will describe restoration activities