This preview shows page 1. Sign up to view the full content.
Unformatted text preview: Hydrographic Hydrog Regime Reg Hydrographic Regime equates with W a v e a n d T id a l E n er g y • Wave Energy (E) ~ Wave Height (H) E ~ H2 Tidal Energy ~ Tidal Range (TR) TR = vertical distance between high and low tide Berm Tidal Range Beach Face Factors Affecting Wave Energy
Width of Continental Shelf
Wide shelves: low energy waves example: Gulf of Mexico Narrow Shelves: large waves example: Hawaii Storm Type and Frequency
New England & East Coast affected by Northeast storms Gulf of Mexico affected by Tropical storms & Hurricanes Storms versus Swell Conditions Case #1 Non-Storm Conditions, Wave Ht averages 2 feet H2 = 4 energy units Case #2 Storm Conditions, Wave Ht is at least 10 feet H2 = 100 energy units S w ell W a v es S to r m C o n d i ti o n s Factors Affecting Tidal Range
1. Width of Continental Shelf
Wide Shelves: High TR Narrow Shelves: Low TR 2. Coastline Configuration
Straight Coasts – No Amplification Indented Coasts – Tides Heightened Coastline Configuration
Very large tidal ranges Land Low to moderate Tidal ranges Tidal Wave forced into constricting bay Ocean Bay of Fundy Bay Fundy
Due to the constriction of the tidal wave the Bay of Fundy has the largest tidal ranges in the World 3 . S iz e o f O cea n B a sin
Tides are a manifestation of a Tidal Wave Rotating within its Basin called a Standing Wave Tides rotate around a nodal point Tides decreases toward the Nodal Point and vise versa Tidal ranges at the Nodal Point equal 0 Small Tidal Basins support a Small Standing Wave So Great Lakes have essentially no tides 4. Proximity to Nodal Point
Hawaii located in the middle of the Pacific so Hawaii has a very small tidal range Norway United Kingdom Germany Tides are a Standing Waves Simplify… T h i n k o f a b a th tu b … Still water Nodal Point Tidal Range High Tide Low Tide Standing Wave Tidal Classification Microtidal: TR < 2m Mesotidal: 4m > TR > 2m Macrotidal: TR > 4m W a v es a n d T id es A ffect B a r r ier C o a st M o r p h o lo g y
• Predominance of wave generated longshore transport of sand versus the onshore-offshore movement of sand by tidal currents • P r esen ce o r a b sen ce o f b a r r ier isla n d ch a in s • Length barrier islands and frequency of tidal inlets • Type of Backbarrier setting; the region between b a r r ier s a n d m a in la n d • Extent of tidal flats and tidal marshes Types of Environments: Barrier- a wave-built accumulation of sand Barrie Tidal Inlet– an opening along barrier chain through which water penetrates Backbarrier– Region between Barrier and Mainland consisting of:
1 . B a y 2 . L a g o o n 3 . M a r s h a n d T i d a l C r e e k 4 . T i d a l F l a ts Tidal Deltas– Sand Shoals on Landward and Seaward side of tidal tnlet Marsh– Salt Marsh Grass region in upper intertidal area, Spartina Grasses Tidal Flats– Sandy to Muddy intertidal area Bay and Lagoons- Open-water Bay
b a ck b a r r ier a r ea s E s tu a r y w i th a b u tti n g m a r s h Mainland
Barrier Island Marsh and tidal creeks Tidal Inlet Ebb-tidal delta O u te r B a n k s , N C M a r sh a n d T id a l cr eek s Estuary and Ebb-tidal delta Jettied tidal inlet Marsh & tidal creeks ...
View Full Document
This note was uploaded on 04/14/2011 for the course GEO 142 taught by Professor Fitzgereld during the Spring '11 term at BU.
- Spring '11