Waves-Only Transport 



For wave-only transport, wave-energy flux or power is used. Wave energy is 

 proportional to the square of breaking-wave height. When including the effects of 

 the group velocity, the volume-transport rate depends on breaking-wave height to 

 the 5/2 power. At Port Huron, the wave hindcast data were used from the 

 offshore location and transformed inshore to breaking using a Snell's Law 

 approach. Longshore-transport rate also depends on the sine of two times the 

 breaking wave angle, also determined from the Snell's law transformation 

 approach. Equation 4 is modified from Equation 6- 7b in USAGE (1992) for 0.78 

 breaking criterion, converting wave height from root-mean-square to significant 

 and for fresh water rather than salt water. 



a =(6.446x10-^ >/f/-5/n(2a,,; 



(4) 



where 



Qi = volumetric sediment-transport rate, m /day 

 Hhr = breaking wave height 

 oibr = breaking wave angle 



Table 4 summarizes transport for waves from each direction (as a percent 

 occurrence) obtained from summary tables in Reinhard, Driver, and Hubertz 

 (1991). The ±17.5 percent uncertainty calculation is based on the uncertainty of 

 each component of Equation 4. Assuming ±5 percent uncertainty for wave height 

 and direction, respectively, translates into a ±17.5 percent uncertainty for Qi 

 (Kraus and Rosati 1998). 



Table 4 



Waves-Only Potential Sediment-Transport Rates 



H 

 m 



T 

 sec 



% 



Dir, deg 



Hb,m 



Dirb.deg 



0,,m^/year 



±17.5% 

 m^/year 



0.61 



4 



15.2 



11 



1.07 



16.5 



230,000 



40,300 



1.22 



6 



2.88 



11 



2.19 



15.7 



250,000 



43,700 



2.07 



7.9 



0.863 



11 



3.73 



15.6 



282,000 



49,400 



2.62 



8.6 



0.657 



11 



4.66 



16.0 



385,000 



67,400 



3.02 



9.2 



0.088 



11 



5.36 



16.1 



72,900 



12,800 



0.61 



4 



13.4 



59 



0.63 



26.1 



79,300 



13,900 



1.22 



5 



4.26 



59 



1.21 



29.2 



138,000 



24,200 



1.86 



6 



0.922 



59 



1.83 



30.0 



85,300 



14,900 



2.35 



6.5 



1.10 



59 



2.29 



31.0 



180,000 



31 ,500 



2.68 



7 



0.213 



59 



2.62 



30.8 



48,800 



8,540 



Total 



1,751,300 



306,640 



26 



Chapter 5 Sediment Transport 



