Sutro

Sutro weirs consist of a rectangular section joined to a curved portion which provides proportionality for all heads above the rectangular section.

Figure 9 - Symmetrical Sutro Weir

For this type of weir, the curved portion is defined by the equation:

And the head-discharge relationship is:

Values of Cd for both symmetrical and non-symmetrical Sutro Weirs are summarized in the tables below.

Cd Values, Symmetrical
a (ft)	b, (ft)
	0.50	0.75	1.00	1.25	1.50
0.02	0.6080	0.6130	0.6170	0.6185	0.6190
0.05	0.6060	0.6110	0.6150	0.6170	0.6175
0.10	0.6030	0.6080	0.6120	0.6135	0.6140
0.15	0.6010	0.6055	0.6100	0.6115	0.6120
0.20	0.5990	0.6040	0.6080	0.6095	0.6100
0.25	0.5980	0.6025	0.6065	0.6080	0.6085
0.30	0.5970	0.0620	0.6060	0.6075	0.6080

Cd Values, Non-Symmetrical
a (ft)	b, (ft)
	0.50	0.75	1.00	1.25	1.50
0.02	0.6140	0.6190	0.6230	0.6245	0.6250
0.05	0.6120	0.6170	0.6210	0.6230	0.6235
0.10	0.6090	0.6140	0.6180	0.6195	0.6200
0.15	0.6070	0.6115	0.6160	0.6175	0.6180
0.20	0.6050	0.6100	0.6140	0.6155	0.6160
0.25	0.6040	0.6085	0.6125	0.6140	0.6145
0.30	0.6030	0.6080	0.6120	0.6135	0.6140

Table 14 - Values of Cd for Sutro Weirs

Note that when b > 1.5 or a>0.30 use Cd =0.6.