LEGEND 



Modeled Longshore Transport 

 Potentiol in m^/yr (COSMOS 2D/3D) 



t 



1 in 



y D 



Deposition in 

 Bottiymetry Depression 



<UULLUX> Accretion 



■ Fftifn Bottiymatry 



Erosion -J co^p"'"""" 



1970-'91 



Dredging 



70.000 m3/yr 



(^^^ Dredging 



MICHIGAN 



Evidence of Onshore Bar Migration 



Due to Water Level Fluctuations 



(1965=low. 1991=hlgh) 



■^X. 



Focus of Erosion Migrating South 



Rote of Erosion/Lowering Is Decreasing 



(-1 to -3 m/period) 



Annual Volume of Lake Bad 

 lion in Panels #4-7 decreased 

 93% from the 1945-"65 Rate 



NOTES: 



1. '64/65 WL -0.2m. '91 WL +O.Bm (IGLD '85) 

 (Influences bar location and exposure of till) 



2. Leas Seasonal Variation in Water Levels (than 45-65) 



3. Cohesive Lowering Estimated at 2.8 m3/m/yr south of harbor jetties 



4. Shoreline Recession Reduced from 1945-'65 Rates 



S. 1964 waUr level all time lo 

 8. Reduced Lake Bed Erosion 



Figure 36. 1965 to 1991 descriptive model 



Chapter 5 Interpretation of Results - A Descriptive Model of Coastal Morphodynamics 



81 



