Equations 16 and 17 can be obtained. For channel networks, the boundary 

 equations for all channels are assembled together with the equations for the 

 interior points and for junctions. 

 Junction conditions 



56. A junction is created if two or more channels meet. A two-channel 

 junction is not necessary because the two channels may combine into a single 

 channel. Therefore, attention will be focused on three-channel confluence or 

 a three-node junction. In Figure 3, the end node of Channel 1 and the 

 beginning nodes of Channel 2 and Channel 3 constitute a junction. A three - 

 node junction provides three equations for the inlet system on the basis of 

 conservation of mass and continuity of the water surface. 



57. Conservation of mass equation applied at Junction 1 in Figure 3 can 

 be written as Equation 18, 



Ci - £>2 - ^3 = (18) 



where 



Qi = flow rate at Node 1 



Q2 = flow rate at Node 2 



Q3 = flow rate at Node 3 



58. In general, at a junction with nodes k, 1, and m, conservation of 

 mass may be written as 



( Qt' - Ot' . Qt') -0 (19) 



59. An independent boundary condition at the junction may be obtained 

 from the continuity of the water surface. This condition can be expressed as, 



(20) 



60. In general, for a junction with node numbers k, 1, and m, the 

 continuity of the water surface may be expressed as 



zt^ - zt^ = 



(21) 



24 



