At a mutual aide recently, we supplied water from a static water source the pumper could not access. We drafted "sucked" from a hard to reach creek using a long hose lay and supplied the pumper "dumped" with 2 three inch lines. Dave Ferbee
The picture here shows another "suck and dump" senario. The pumper could not cross the small bridge. The vacuum tanker "sucked" from the creek and "dumped" into the portable tank for the pumper to draft from and apply water to the fire.
To those Departments who do this, in the heat of the moment remember to allow time for pressures to equalize between draft and discharge. In extended operation times, be sure the secondary shut off is drained.