Mc bride, aundrea tribal habitat conference 2010 final

811 views
764 views

Published on

Published in: Travel, Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
811
On SlideShare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
1
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Mc bride, aundrea tribal habitat conference 2010 final

  1. 1. Tribal Habitat Conference 2010 Aundrea McBride and Eric Beamer Skagit River System Cooperative
  2. 2. Camano Island State Park Possession Park
  3. 3.  If we restore habitat, will salmon and other fish use it?  Will restored habitat be sustainable ?  Will a restored site become tidally inundated?  Will the channel be open in ~100 years?  What are the landscape-scale considerations for restoration ?
  4. 4. Fish Prediction Based on Compilation Assemblage from Skagit Bay Pocket Estuaries  Juvenile chum and wild Chinook salmon dominate the assemblage early in the year  followed by staghorn sculpins in late spring,  shiner perch and sticklebacks in summer, and  surf smelt in early fall. (Beamer et al. 2007).
  5. 5. high tide low tide flood tide ebb tide The existing marsh will get wet if connected to Possession Sound
  6. 6. high tide ebb tid low tide flood ti
  7. 7. Low Tide Flood High Tide Ebb
  8. 8. To predict the critical shear stress for clearing sediments from the inlet channel deposited by longshore drift
  9. 9. crit = Rg(s – f)Dj where crit = the critical shear stress value for the Dj measured in Pascals, j =the grain diameter cumulative frequency by weight (dimensionless), s = the sediment density (2.65 kg m-3 ), f = the density of marine water (1.025 kg m-3 ), g = the acceleration due to gravity (m/sec2 ), and R = 0.003 is Shield’s parameter for gravel dominated sediments. Table 1. Comparing crit to the bed shear stress calculated by the hydrodynamic model. Scenario crit D50 (PA) crit D75 (PA) bed from model (PA) peak velocity from model (m/s) 1 4.18 11.47 10 1.77 2 4.18 11.47 10 1.59
  10. 10. Table 1. Comparing crit to the bed shear stress calculated by the hydrodynamic model. Grain size fraction by weight Grain diameter (mm) crit (Pascals) bed (Pascals) peak velocity from model (m/s) D50 5 2.39 10 1.97 D65 9.6 4.59 10 1.97 D80 13.5 6.45 10 1.97 D85 20 9.56 10 1.97 D90 25 11.95 10 1.97
  11. 11. To predict if the proposed inlet channel size will be at equilibrium relative to the pocket estuary size based on a regression of width to size ratios for similar, stable pocket estuaries in Whidbey Basin.
  12. 12. Relationship Between Inlet Channel Width and Pocket Estuary Area y = 9.8837x0.4154 R2 = 0.473 p = 0.013 y = 3.8879x0.5152 R2 = 0.9063 1 10 100 1000 10000 0.1 1 10 100 1000 10000 100000 total intertidal area (ha) inletchannelwidth(m) Whidbey Basin pocket estuaries Williams et al. 2002 San Francisco Bay data scenario2 scenario1
  13. 13. Relationship Between Inlet Channel Width and Pocket Estuary Area y = 9.8837x0.4154 R2 = 0.473 p = 0.013 y = 3.8879x0.5152 R2 = 0.9063 1 10 100 1000 10000 0.1 1 10 100 1000 10000 100000 total intertidal area (ha) inletchannelwidth(m) Whidbey Basin pocket estuaries Williams et al. 2002 San Francisco Bay data
  14. 14.  Scenario 1 is probably too small to be sustainable based on comparison, but scenario 2 could be sustainable based on size (just barely)  Scenario 2 would require inlet channel clearing or some type of engineering solution to clear the coarsest 25% of sediment
  15. 15.  This site is on the small end, but it is probably sustainable if restored. Channel clearing could be improved by 2 factors:  The inlet could be located down drift from the boat ramp to divert the coarsest 15% of sediments.  The hydraulic head due to freshwater has not been considered and will improve inlet bed shear stress for clearing sediment, especially in the winter when the coarse sediment will be coming through.
  16. 16. Landscape-Scale Context

×