CSO Discharge characterization

[coolscheid]

I have a CSO structure where I need to characterize the outflow. The chamber has a tide gate (rectangular cast iron flap gate with bronze seals). I plan to use a meter to record the depth in the CSO inlet, then characterize the flow to the interceptor with a submerged orifice equation, but I am not sure if I can characterize the tide gate outfall using a mathematical equation. Can anyone provide me with a resource to understand how to calculate the out flow? Is this a reasonable approach to define the volume of water discharging from the CSO?

 

[RWF7437]

Assuming "CSO" means Combined Sewer Overflow and that by "characterize" you mean calculate the outflow. Have you tried contacting the flap gate manufacturer or looking in their catalog? They should have head capacity curves based on testing published somewhere.

good luck

 

[LHA]

I would do what RWF suggests, but if you can't find that, you will need to know the weight of the gate, assume neglible hinge resistence compared to weight of gate. Then run a force analysis using the delta headwater:tailwater and weight.

BUT the headwater is variable based on the storm hydrograph, and the tailwater is variable based on time/tide period. Yikes, sounds like a complex task!

Hopefully, you just need a worse case scenario at a given tailwater, which would be reasonable for the peak period of a storm? Then, you could just set up a stage:discharge curve and route the inflow.

Remember: The Chinese ideogram for “crisis” is comprised of the characters for “danger” and “opportunity.”
-Steve