275. Line G.6: IXDB(I) Enter the grid cell numbers of the tips of 

 detached breakwaters IXDB(I) in ascending order of cell number. There 

 should be two values for each detached breakwater located entirely within the 

 calculation grid and one value for each additional detached breakwater 

 extending across the calculation boundary. 



276. Line G.7: YDB(I) Enter the distances from the tips of the 

 breakwaters to the x-axis YDB(I) in ascending order of cell number. There 

 should be the same number of values as specified at Line G.6. 



277. Line G.8: DDB(I) Enter the depths DDB(I) at the tips of the 

 breakwaters in ascending order of cell number. There should be the same 

 number of values as specified at Line G.6. 



278. Line G.9: TRANDB(I) Enter the value of the wave transmission 

 coefficient TRANDB(I) (called "K T " in the main text) for the individual 

 breakwaters (NDB values) in ascending order as the structures appear on the 

 grid. This empirical coefficient accounts for wave transmission through a 

 breakwater and by overtopping, and it must be evaluated either externally or 

 as part of the calibration process, similar to the case of groin/ jetty 

 impermeability. The value of the wave transmission coefficient varies between 

 0.0 and 1.0 , where the value 0.0 describes a high, impermeable breakwater 

 with no wave transmission through the structure by any means, and the value 

 1.0 describes a completely wave -transparent, ineffective structure. 



H. Seawalls 



279. A seawall constrains the allowable position of the shoreline 

 because the beach cannot erode landward of the wall. Formally, GENESIS can 

 describe only one seawall. However, noncontiguous sections of a seawall can 

 be represented by placing the number -9999 in the SEAWL input file along the 

 shore where seawalls are not present. Values of -9999 are assumed to place 

 the seawall at locations so far landward that the wall would never come into 

 play in the longshore transport and shoreline change calculations . 



280. Line H.l: ISW If there is one or more seawall sections along 

 the modeled beach, the value 1 ("yes") is entered here for the flag ISW . 

 If there are no seawalls, the value ("no") is entered and Line H.3 can be 

 skipped. (If the value is entered at Line H.l, Line H.3 will not be read 

 by GENESIS, and values remaining at Line H.3 may be arbitrary.) If there are 



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