A flood pump includes a pump housing having a pump housing inlet and a pump housing outlet, an impeller housing disposed in fluid communication with the pump housing between the pump housing inlet and the pump housing outlet, an impeller disposed in the impeller housing, a power unit drivingly engaging the impeller, a diversion conduit disposed in fluid communication with the pump housing between the pump housing inlet and the pump housing outlet and a pump housing outlet valve in the pump housing between the diversion conduit and the pump housing outlet.