

At 

 Ay 



-^-^^,.^6 





az,,. Ay (a,, J ^^^ ^Ay ^^t 



.^At-i4l-il:ile.ffAt J^xJldle ^^^^ 



2 ^i-i azi.i 





= 1 -2 ^^ ^^ e.^ V^ 



2 Ay Aj 2 ■ 



3F,, _ 



1 .2 ^'^ ^-^ e.g At ^ 



2 Ay A,,, ^ 2 ^ 



•if^-^V (34) 



"'^l ac^.i ai?i*i 



(35) 



External boundaries 



68 . If the external boundary is given as the value of the water surface 

 elevation at the beginning node of a channel, Equation 16 applies. The 

 boundary Equation 16 is denoted F2i-i, and its partial derivative is given as, 



29 



