Pumping station in a water flow system

A water flow system for collecting and discharging waste water, storm water and the like wherein water inflow rates may fluctuate widely and unpredictably, said water flow system comprising a water pumping station, an inflow main for delivering inflowing water to said pumping station, and a discharge main for receiving water outflowing from said pumping station, said pumping station comprising a water collection well having a basin area for receiving inflowing water from said inflow main, a pair of centrifugal water pumps each having a suction inlet and a pressure outlet, conduit means communicating said suction inlet of each said pump with said basin area of said water collection well and communicating said pressure outlet of each said pump with said discharge main, said conduit means including a pair of suction conduits individually communicated respectively with said suction inlets of said pumps, a pair of discharge conduits individually communicated respectively with said pressure outlets of said pumps, means communicating each said discharge conduit with said discharge main, and a secondary diversion conduit branching from the discharge conduit communicated with one said pump and being communicated with the suction conduit communicated with the other said pump for communicating said pressure outlet of said one pump with said suction inlet of said other pump, and control means for actuating and deactuating said pumps, said control means including means for detecting water inflowing into said pumping station from said inflow main, means for actuating one said pump when the detected water inflow exceeds a predetermined minimum value, and means for additionally actuating the other said pump in series with the first-actuated pump when the detected water inflow exceeds a predetermined maximum value for serial flow of water through said pumps to correspondingly increase the rate of water outflow from said pumping station, said pumps being selected to have respective pumping capacities which individually are less than a predetermined maximum head valve for said water flow system but which in serial combination upon simultaneous actuation of both said pumps exceeds said predetermined maximum system head valve, thereby to enable said pumping station to effectively discharge widely fluctuating inflows of water.