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(800) 438-6057 • (704) 528-9806 • Fax: (704) 528-5478

> Interceptor > System Design > Channel Outlet

Catch Basin Hydraulic & Channel Outlet Design

Once total trench flow is determined and all site conditions have been considered, match the outlet type and size to these factors. For discharge directly from the channel, refer to Table A and Table B for vertical and horizontal outlet plate capacities. For catch basin discharge rates, refer to Table C. When the Interceptor is used in conjunction with traditional inlets or manholes, a vertical miter outlet can be used without restricting the flow.

TABLE A — Vertical Pipe Discharge Capacity

	Flow in m³/s (cfs)
Channel #	100mm (4") dia.	150mm (6") oval
021	0.010 (0.342)	0.019 (0.652)
050	0.011 (0.371)	0.020 (0.707)
091	0.012 (0.407)	0.022 (0.774)
100	0.012 (0.415)	0.022 (0.790)
150	0.013 (0.455)	0.025 (0.866)
191	0.014 (0.484)	0.026 (0.922)
200	0.014 (0.491)	0.027 (0.935)
250	0.015 (0.525)	0.028 (1.000)
291	0.016 (0.551)	0.030 (1.048)
300	0.016 (0.557)	0.030 (1.060)

TABLE B — Horizontal Pipe Discharge Capacity

	Flow in m³/s (cfs)
Channel #	100mm (4") dia.	150mm (6") oval
050	0.008 (0.277)	N/A
100	0.009 (0.332)	N/A
150	0.011 (0.379)	N/A
200	0.012 (0.421)	0.020 (0.707)
250	0.013 (0.459)	0.022 (0.791)
300	0.014 (0.494)	0.025 (0.866)

TABLE C — Catch Basin Discharge Capacity

	Flow in m³/s (cfs)
Catch Basin #	100mm (4")	150mm (6")	200mm (8")	250mm (10")	300mm (12")
610	0.267 (0.94)	0.060 (2.12)	0.107 (3.76)	0.167 (5.88)	0.240 (8.47)
611	0.034 (1.18)	0.075 (2.66)	0.134 (4.74)	0.210 (7.40)	0.302 (10.7)
900	0.022 (0.79)	0.050 (1.77)	0.089 (3.15)	0.139 (4.92)	0.201 (7.08)

Notes: Head = Bottom of Grate
For discharge capacity requiring 15" and larger piping, contact ABT.