Table 4-13. Classification of Elements in the Littoral Zone Sediment Budget 



*Naturally occurring sources and sinks that usually are major elements in the sediment budget. 



It is often useful to specify a source or sink as a fraction, k^, 

 of the gross longshore transport rate: 



Q,- = k . Q. 



s 



(4-47) 



In a complete sediment budget, the difference between the sand added 

 by all sources and the sand removed by all sinks should be zero. In the 

 usual case, a sand budget calculation is made to estimate an unknown ero- 

 sion or deposition rate. This estimated rate will be the difference result- 

 ing from equating known sources and sinks. The total budget is shown sche- 

 matically as follows: 



Sum of Sources - Sum of Sinks = 0, or 



Sum of Known Sources - Sum of Known Sinks = Unknown (Sought) 



Source or Sink 



= 



(4-48) 



The Q| are obtained using Equation 4-46 and the appropriate q^ and 

 hi. The subscript, i, equals 1, 2, 3, or 4 and corresponds to the sub- 

 scripts in Table 4-13. 



4-118 



