A system includes a pump for connecting to a fluid source. The system also includes an adjustable-speed drive coupled with the pump. The system further includes a flow meter coupled with the pump. The system also includes a processor coupled with the adjustable-speed drive and the flow meter for receiving an approximately instantaneous power consumption and an approximately instantaneous pumping rate. The processor is configured to select an optimal pumping rate for operating the pump based upon a comparison of metrics representing approximately instantaneous pumping rates and approximately instantaneous power consumptions.