Unformatted text preview:

Reading MaterialPuget Sound MorphologySlide 3Bathymetry (water depth)Slide 5Slide 6Slide 7Slide 8Hydrography (water properties)Slide 10Slide 11Types of river-mouth environmentsPuget Sound SedimentationSlide 14Mechanisms associated with SedimentationSlide 16Slide 17Slide 18Slide 19Slide 20Slide 21Reading Material“River Deltas”from “The Coast of Puget Sound”J.P. Downing, Puget Sound BooksPuget Sound MorphologyGlacial Originscour – flow under ice sheetformed depressionse.g., Main Basin, Hood Canal, Lake Washingtonsedimentary deposits – also raised land surfaceglacial tills, outwash deposits, lake depositsold glacial sediment now provides new input to PScliff erosionlandslidesland surface erosionBathymetry (water depth)Shallow entranceglacial origin – moraineoceanographic name – sillprimary sill is Admiralty InletSeveral others divide PS into separate basins (>200 m)Main Basin has 46% of water volumeSinuous shape – result of originSouthern Basin has 29% of shorelinesFluvial (river) sediment supplyfills PS from shorelineWhidbey Basin has 43% of tidelandsHydrography (water properties)Salinity (amount of salt dissolved in water)river water has 0 ppt (parts per thousand)ocean water has ~35 ppt – differs around worldbrackish water at depth in PS – 20-30 pptDensity (low salinity = low density)river plume flows over more dense brackish waterInput of river water - varies with space and timenorthern PS rivers supply the most watersmall input during late summerlarge input during late autumn and winter rainslarge input during spring snowmeltTypes of river-mouth environmentsestuary – semi-enclosed setting river and salt water meet and mixfjord – estuary with glacial origin deep, with shallow sill near mouthdelta – river mouth receiving much sediment estuary filled with sediment shoreline growing seawardPuget Sound SedimentationSources of sedimentshallow – shoreline erosion, landslidesdeep – biological productivity, algal debris much carbon decomposes, forming methane gasall depths – river discharge deltas form near river mouths river plume carries sediment deepernear sill – inflow with deep ocean waterMechanisms associated with Sedimentationplume transport – turbid surface waterriver momentum, tides, windflocculation – silt and clay particles form larger aggregates, which sink quicklylandward bottom flow – traps sediment near riverdelta formation – thick deposits near river mouth topset = tidelands foreset = steep surface, rapid accumulation bottomset = deep deposits, escape seawardDuwamish deltaIntensely impacted by humansWetlands hardened (landfill, roads, parking lots, buildings)Distributary channels altered and stabilizeddepth in mDuwamish delta4-m resolution, 5x VENisqually deltanearly natural conditionSeveral distributary channels bring water and sediment across delta to Puget SoundNisqually Delta, 5x VE3-m resolution, looking SWdepth inmeterspitchyawrollheave&squatpositiontidewater-column sound


View Full Document

UW ESS 230 - Lecture Notes

Documents in this Course
Soils

Soils

36 pages

Erosion

Erosion

37 pages

Soils

Soils

37 pages

Erosion

Erosion

34 pages

Rivers

Rivers

42 pages

Soils

Soils

37 pages

Soils

Soils

36 pages

Erosion

Erosion

35 pages

Load more
Download Lecture Notes
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Lecture Notes and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Lecture Notes 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?