A pump intake pressure control apparatus includes an intake conduit joining a pump to either a pressurized or unpressurized liquid source, a wide-range flow controller configured to control the flow of liquid through the intake conduit, pressure sensors for detecting the pressure of the liquid in the intake conduit upstream and downstream of the flow controller, and an electronic master controller programmed to receive input from the pressure sensors and to actuate the wide-range flow controller to maintain the pressure downstream of the wide-range flow controller at or below a predetermined desired value. In one embodiment of the invention, the wide-range flow controller is a branched portion of the intake conduit having a valve in each branch. In another embodiment of the invention, the flow controller is a gate valve having a stationary triangular blocking member projecting into the passage between the inlet and outlet ports of the valve.