WATER LEVEL VARIATIONS, WAVE RUNUP OVERTOPPING

WATER LEVEL VARIATIONS, WAVE RUN-UP & OVERTOPPING Wave Classification: Spectrum Water Level Variations • astronomical tides • tsunamis • seiches • wave setup • wind setup • storm surge • climatological variations Tsunamis Deep water: Lo=200 km, Ho=1 m, T=17 min, Co=700 km/hr Shallow water: H=11 m, C=30km/hr 1957 Aleutian Tsunami @ O’aho Seiching Wave Setup Wave Setup Wind Setup and Storm Surge Primary factors: • characteristics of storm • hydography of basin • initial state of system Other factors: Astronomical tides, atmospheric pressure differences, earth’s rotation, rainfall, surface waves, storm motion effects surge Hurricane Isabel Sept 18, 2003 wave height FRF, Duck Kitty Hawk Hatteras Village Main Items • statistical properties of waves • determine wind input for wave predictions • calculate wind-generated waves • understand various mechanisms for water level variations Implications of Wave Run-up Structure Run-up/Overtopping Beach/Dune Processes Wave Runup & Overtopping Delft Report by Van Der Meer and Janssen replaces pages 7.16-7.99 Ru2%= runup level exceeded by 2% of the waves Wave Runup & Overtopping revetment design water level Wave Runup Height Ru 2%  1.6   h  f    b  op  max   Hs  3.2   h  f  op  tan  Sop  b op   b  op  Sop  H s / Lo Wave Runup Height Ru 2%  1.6   h  f    b  op  max   Hs  3.2   h  f   b op   b  op  h = reduction factor for shallow foreshore f = reduction factor for slope roughness  = reduction factor for wave angle b = reduction factor for berm op  tan  Sop Sop  H s / Lo Reduction for Slope Roughness f Reduction for Shallow Foreshore  h   h   0.03   m  , Hs   hm 4 Hs  h  1, hm 4 Hs h b Influence of Berm Width factor: rb = - taneq /tan Location factor: rdh=0.5(dh/Hs)2, 0