All station interior and footing drains shall be drained to natural drainage. If there is a reservoir and if elevations permit, these drains shall connect to the reservoir overflow for discharge to the storm drains.
If gravity drainage is not feasible from the pumping station because of the location and elevations, the pumping station drains shall be led to an adequately sized drain sump and pumped out. There shall be two close-coupled, submersible sump pumps. One of the pumps shall be sized for the normal expected drainage flows and shall have built-in float switch for on-off control. The other pump shall be sized for four or five times the normal flow.
A pressure tube type flood sensor, Vigiltrol by Autocon or equal, shall be located at a suitable point near the sump, on the pump floor to start the large sump pump, to transmit station flooding alarm via telemetering to the WSSC Control Room, and to stop all pumps (if considered necessary).