stormwater pump station

There is no one answer here, it is very much dependent on your council's requirements
you need to develop a hydrograph of your design storm and then route it through a model of the detention and pump system. You can use free software like EPA SWMM to do this, but make sure your time steps are short enough to accurately model the pump operation. In some situations providing additional volume is much cheaper than increasing your pump size

here are some resources

swazimatt said:

There is no one answer here, it is very much dependent on your council's requirements
you need to develop a hydrograph of your design storm and then route it through a model of the detention and pump system. You can use free software like EPA SWMM to do this, but make sure your time steps are short enough to accurately model the pump operation. In some situations providing additional volume is much cheaper than increasing your pump size

here are some resources

https://onlinepubs.trb.org/Onlinepubs/trr/1983/948/948-010.pdf

https://pdhonline.com/courses/c362/FHWA-NHI-01-007.pdf

https://www.waternz.org.nz/Attachment?Action=Download&Attachment_id=521

Click to expand...

Hi, I'm also looking to design a Stormwater lift station for a condo garage along the coast. Can you expand on council requirements? I haven't been able to find much. FDOT (not the governing agency) uses 5 year storm for general design, I had initially proposed 10 year but I'm struggling with two ideas. One being water sitting in the garage for god knows how long and two a large storm flooding the entire place.

I read through your resources and they gave me more ideas but nothing really on the hydrology side of things for a situation like this. Do you have any experience/advice?

Sizing wet wells for stormwater involves determining the appropriate capacity to accommodate peak inflows and ensure efficient pumping operations. Key factors include inflow rates, pump cycle times, and the need to minimize frequent pump cycling and excessive retention times. Use the volume of the incoming drainage piping as part of the wet well volume.

The design should consider the peak runoff rate from a specific design storm. The peak runoff rate is calculated using methods like the Rational Method, determines the volume of water entering the wet well. The pump station should be able to pump the peak runoff rate.

Wet well volume depends on the method of pump operation. If you use variable speed pumps and the pumps match the flowrate to the inflow, the wet well volume may be small. This time is normally less than 1 minute retention. That time will allow for the change in capacity with a pump is started or stopped before the next start or stop point is reached.

Sufficient storage volume is needed between pump start and stop elevations to meet minimum cycle time requirements. Frequent pump cycling can damage pumps. Too small of a wet well volume can lead to frequent cycling,. The maximum number of starts per hour for lift stations is typically 6. Pump cycle time equals 60 minutes divided by the starts per hour, so the maximum pump starts per hour of 6 equals a 10 minute cycle time