DYNLETl 



Model setup 



168. The Indian River Inlet System is represented in DYNLETl by 



31 cross sections distributed in three channels. The channels are numbered 

 from 1 to 3 and there is a single junction numbered 1, as shown in Figure 12. 

 The channels and their cross sections are listed in Table 3. 



169. The assumed initial flow direction is from the sea toward the 

 bays. Cross Section 1, represented as Node 1, is taken at the location of the 

 CERC tide gage. Channel 1 extends from the sea through the inlet throat to 

 Indian River Bay. Channel 2 simulates Indian River Bay, and Channel 3 

 simulates Rehoboth Bay. Mid Island lies within Channel 3. Channels 1, 2, and 

 3 meet at Junction 1, the only junction in the model. Junction 1 consists of 

 Nodes 20, 21, and 25. 



170. The required cross -sectional geometric data were taken from 

 hydrographic maps obtained from the USACE District, Philadelphia, dated 

 3 March 1989. The data are recorded as distances and elevations, where 

 distance is an offset from the left bank, and elevation is with respect to the 

 bottom with the MLW datum as the reference level. 



171. Manning's coefficient of friction was initially specified at every 

 cross -section point as 0.03 and as a first estimate. After a few trial runs, 

 the value was changed to 0.045 in Cross Sections 5 through 12, which encompass 

 the bridge area. This decision was made by examining plots of calculated 

 velocity and observation of large bed irregularity on the hydrographic charts 



Table 3 

 Channel Cross Sections. Indian River 



Channel Channel Cross Section 



Number From To 



1 1 20 



2 21 24 



3 25 31 



68 



