The Scottish Rural Property and Business Association (SRPBA), which has provided the figure, said private landowners and estates supplied staff, specialist equipment and paid for helicopters to water-bomb flames.
They have also been building a dam of hundreds of sand bags around the bomb site to pump water out in preparation for the delicate task of defusing the device.
The British bomb in Koblenz, now covered by just 16 inches of water, is thought to have been dropped in the night of Nov. 6, 1944, when Royal Air Force planes blanketed Koblenz with bombs and destroyed much of the inner city.