Inland Aquaculture Engineering (1984) 
DESIGN AND CONSTRUCTION OF FRESHWATER FISH FARMS 
Chapter 8. Hydraulic Formulas Used in Designing Fish Farms 
3. DESIGN FORMULAS FOR HYDRAULIC STRUCTURES 
3.2 Design Formulas for Inlets 

_{}
where
Q = design discharge of the inlet, l/sec
B = width of the throat, cm
H = height of the designed full supply level in the feeder channel above the sill level of the inlet
C = discharge coefficient
Table 10 Values of Discharge Coefficient C for open Flume Inlet
B in cm 
C 
6 to 10 
0.0160 
10 to 15 
0.0164 
over 15 
0.0166 
Length of the cistern: 
l_{c} = 0.82 H_{2}, m  
Depth of the cistern: 
d_{c} = 0.1 H_{2}, m  

where 
H_{2} = water depth in the pond, m 
Depth of the glacis 
d_{g} = 0.5 H, m  

where 
H = maximum water depth above the sill level of the inlet, m 
Example 3
Design an open flume inlet for a discharge of 150 l/sec if the water depth in the feeder canal is 45 cm and 1.50 m in the pond.
Solution
The corresponding width of the throat to the water depth of 150 l/sec is defined from Figure 9.
then
B = 30 cm
d_{g} = 0.5×H = 0.5×0.45 = 0.23 m
l_{c} = 0.8×H_{2} = 0.8×1.50 = 1.20 m
d_{c} = 0.1×H_{2} = 0.1×1.50 = 0.15 m