How to size sump pit for rainwater if the flowrate of the water is 45l/s

How to size sump pit for rainwater if the flowrate of the water is 45l/s

I miss understood your original question.

If you need to be able to handle an incoming flow rate of 45 liters / second and want wait a total of 4 minutes before the pump comes back on at full flow rate your pit will need to be big enough to handle the switch hysteresis.

In 4 minutes the in coming volume will be 45 liters x 240 seconds or nearly 11,000 liters (11 cu meters). That is a lot of water. Assuming that you float hysteresis is 10 cm the area of the pit will be 110 square meters. That is a huge sump.

What are you draining?

Niel

When sizing a sump pump you need to know two things

1. Volume of water to be moved. You are indicating that you need to remove 45 liters per second.

2. How high you need to lift the water.

Once you know that both those things you can properly size the pump.

Please note: If there is a lot of pipe after the highest point in the system you may need to adjust the effective total lift.

The pump itself will have the correct outlet or pipe diameter to transfer that amount of water. Be sure that you do not use a smaller pipe or tube.

Niel

Thank you Niel,

The pump capacity I use is 45l/s at 15m head. To avoid pump start/stop frequently and pump will start after 4 minutes water flow in to the pit (basin). what is suitable pit (basin) size to be provided.

I’m designing sump pit for rain water at lower ground and be pumping to the discharge drain at level ground. In Malaysia our rain water intensity is very high about 200mm