and yet narrow enough to protect the smallest conduit in the system downstream of the barrier. It shall be the designer's responsibility to provide a debris barrier or deflector appropriate for the situation.
Other Closed Conduit Criteria
Angle of Confluence - In general, the angle of confluence between main line and lateral shall not exceed 30 degrees under any of the following conditions:
Where the flow (Q) in the proposed lateral exceeds 10 percent of the main line flow.
Where the velocity of flow in the proposed lateral is 20 fps or greater.
Where the size of the proposed lateral is 60 inches or greater.
Where hydraulic calculations indicate excessive head losses may occur in the main line due to the confluence.
Connector pipe may be joined to main line pipe at angles greater than 30 degrees up to a maximum of 90 degrees provided none of the above conditions exist. Connections shall not be made to main line pipe which may create conditions of adverse flow in the connector pipes.
The velocity in pipe shall not exceed 40 fps. For velocities from 20-30 fps, the minimum cover over steel in the pipe shall be 1/2 inch greater than the normal cover (1-1/2" minimum). For velocities from 30-40 fps, the minimum cover over the steel in the pipe shall be 1 inch, greater than the normal cover (2" minimum).
Open Channels - Open Channels will be designed in accordance with "Los Angeles County Flood Control District Design Manual, Hydraulic", dated (Latest Edition.)
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