2. One more concept from Airy Wave Theory … Wave Period Does Not Change!

3. Littoral Sediment Budgets

4. Contributions from Riverine Sources
Best and Griggs (1991) - Santa Cruz Littoral Cell
Map and Budget

5. Total and Littoral Suspended Load
used these rating curves along with probabilities of discharge events to estimate riverine contribution.

6. Bed Load and Discharge
so ... just determine combine the rating curves with frequency of event to get mean annual contribution from streams/rivers, right? What’s the assumption?

7. Contribution from Sea Cliffs
18-20% is the estimate from Best and Griggs (1991)

8. Contribution from Sea Cliffs
Lidar study by Young and Ashford, 2004
77,000 m3/yr from sea cliffs

9. Kujykuri Beach, Japan (Sunamura and Horikawa, 1977)
work through the budget - does it work?

10. Setting
I’ll give you the lay of the land here, we’re in southcentral Alaska on the Kenai peninsula along the Eastern side of Cook Inlet, several volcanos across
the inlet, one of which was making some noise recently.
The city of Homer sits on the North shore of Kachemak Bay. Dramatically different landscapes on either side of the Bay - glacially etched peaks in the
Cretaceous metasedimentary rocks to the south, foreland basin layercake strata to the north. And you can see the lithologic contrast on either side of the
Border ranges fault is exhibited quite clearly in the geomorphology. High relief peaks, valleys, and fjords on the southeast side - low relief planes and
wetlands on the northwest side.

11. Homer Littoral Cell (HLC)
Anchor River Mouth (source?)
Sea Cliffs (source)
Lesser Streams (source?)
K-Bay Submarine Trough (sink)
To the best of my knowledge, this littoral cell is heretofore undefined. I’d like to point out:
Anchor point start of littoral cell, but I don’t think the Anchor River contributes much to the littoral system because all the sedimentary features
at the river mouth flare to the north, indicating northerly littoral transport at that point, which makes sense if you think that the dominant wave field
approaches from the west and splits along the coast at Anchor Point
(2) coastal streams with very small catchments,
(3) sea cliffs as a possible source - yes
(4) Homer spit, which has grown to a maximum extent because of the presence of (5) sink - submarine trough.

12. Calculation of sea cliff retreat rate
Qv = 4,400 – 6,300 m3/yr
L = 30 km
b = 10 m
f = 0.15
Ok, so here’s a view of the Homer Littoral Cell - Anchor point Is up around this corner, Munson Point is here, our Argus tower is that speck,
and it’s a view at lowish tide. If we assume that the riverine input of sediment to the littoral system is negligible, because the catchments are so small,
then all of the sand moving through the cell is coming from sea cliff retreat, and this relationship ought to describe that retreat rate.
L is the total length of cliffed coastline within the littoral cell, b is the mean cliff height, and f is the fraction of littoral sand in the cliff face -
here assumed to be small because it’s just a thin little carapice of sandy terrace deposits perched on top of the Tertiary strata.
Then we get a value of 9-14 cm/yr for sea cliff retreat. How does this compare with what’s been observed?
Estimated contribution from Sea Cliffs = 100% ?
R = cm/yr

13. Barrier Island sediment budgets
Oregon inlet migration is 23 m/yr southward and 5 m/yr landward
QLST = 500, ,000,000 m3/yr

14. Littoral Cells Inman and Chamberlain, 1960
coasts divided up into a series of compartments
Inman and Chamberlain, 1960

15. Lowstand (and Highstand) fan deposition
The sinks of the system - turbidite fans
Story of their activity is widely debated.
Covault et al., 2007

16. Paleo- vs. Modern sink behavior

17. Subcells - Bowen and Inman (1966)
Identified offshore sources?