Mar. 6,1916 
Flow through Weir Notches 
1071 
Table IV. —Equations for straight lines representing discharges through rectangular 
weir notches 
Length of crest. 
Equations of line. 
Feet . 
*■ 00 5 5 
1. 5026 
2.0057 
2.9970 
4.0056 
e= 3 .o78LH 1 - 463 
£?=3.io6LH 1 * 465 
(3= 3 .i25LH 1 - 466 
S=3.i 54 L// 1 * 467 
e= 3 .i 7 2LH 1 - 473 
The coefficient values ( C) in the above equations were plotted 
(fig. 8) against the lengths of crests (L), and the exponent values 
Fig. 8 .—Curve showing relation of coefficients (C) to lengths of rectangular notches. 
(n) were plotted (fig. 9) against the lengths of crests (L). Average 
straight lines drawn to represent the points were found to have the 
equations C= 3.078L 1 * 022 and n — 1.46 + 0.003L. 
Substituting these values of C and n in the equation Q = CLH n , the 
formula for the discharge through rectangular notches was found to be 
Q = 3 .oSL 1 - 022 # ( L46 +- 0031 '). 
This formula gives discharge values that agree within a maximum of 
0.7 per cent with the values indicated on the curves plotted from the 
experimental data, but the average variation is only 0.26 per cent. 
Table V gives the discharges through the notches used, computed by 
the curve and by the straight-line formulas, also the values indicated on 
the curves plotted from the experimental data. 
