(d) River water levels were measured at 30-minute intervals 

 using a stilling well located near the inlet mouth (Fig. 2). 



(e) The time step was estimated as: 

 1900 



At 



/32,2 X 2 



= 250 seconds 



(f) Loss coefficients were specified as CDF = CDE = 1.0, and 

 Manning's n was estimated as n = 0.055 - 0.005 D (recommended for 

 depths less than 4 feet) . 



(g) A preliminary computer run using a sinusoidal river tide 

 showed that the inlet is controlled by friction effects and that 

 temporal acceleration is not important. 



(h) The model was then run using the measured river water 

 levels to force the model (Fig. 4). It was determined that the 

 model adequately predicted bay levels. 



(i) No additional prototype data are available for verifi- 

 cation of the model. 



(j) The model is now available to use for predictions of in- 

 let hydraulics. In this example, a second inlet (inlet 2), is 

 being considered for this site, so the model is used to predict 

 hydraulics for the system with two inlets (Fig. 2) . Procedures 

 (a) and (b) are repeated for the second inlet. In this case, the 

 second inlet is modeled by one channel and two cross sections so 

 that the inlet has a length of 300 feet, a width of 50 feet, and 

 a depth of 4 feet. These inlet data are put into the computer 

 format, added to the program deck for the natural inlet, and re- 

 run to predict conditions for the proposed two-inlet system. The 

 numerical model predicts that addition of the second inlet would 

 increase the tidal range and the tidal prism in the bay and would 

 cause water velocities in inlet 1 to decrease (see Table] . 



Table. Predicted Cabin 



Point Cree 



k hydraul 



ics. 



Tide 



24 and 25 

 May 1976 



Model prediction 

 for second inlet 



Inlet 1 



Inlet 1 



Inlet 2^ 



Bay 



(range in ft) 



0.36 



1.49 



1.49 



Ebb 



(maximum velocity in ft/s) 



-0.6 



-0.3 



-1.3 



Flood 



(maximum velocity in ft/s) 



0.9 



0.3 



1.7 



NOTE: 



300 feet, B = 50 feet, D = 4 feet. 

 ; Tidal range in the sea is 1.49 feet. 



13 



