This is coolbert:
Yet once more an extract from the David Irving book :
"THE RISE AND FALL OF THE Luftwaffe The Life of Field Marshal Erhard Milch"
"an unexpected drought: by mid-November it was recognized that the drought would be so severe that during mid-November  there would be less aluminium available than ever before. This new limiting factor was disclosed by Speer to Milch in mid-November and Milch had no option but to accept it."
"The drought was the worst for ninety years in Germany. The loss of hydro-electric power would cause considerable production losses of nitrogen, high-grade steels, synthetic fuels and aluminium."
"Moreover, the Danube was so low that oil barges from Romania could carry only 300 instead of 700 tons each; in November the amount transported would be 80,000 tons compared with 144,000 tons in October, and there were 323,000 tons waiting in Romania to be shipped to Germany. Of Reich aluminium production, estimated at 40,000 tons a month for the next few months, the Luftwaffe would now be allocated 22,000 tons a month."
It can be reasonably inferred almost with absolute metaphysical certitude that drought as was the case in central Europe during the year 1943 DID MORE DAMAGE TO THE GERMAN WAR PRODUCTION AND MANUFACTURING CAPACITY THAN THE COMBINED STRATEGIC AERIAL BOMBARDMENT OFFENSIVE OF THE ALLIED AIR FORCES! [American and British]
Reservoirs in the Italian Tyrol and Ruhr [?] areas not filled to capacity, those dynamos and generators not able to function at 100 % capacity 100 % of the time. Electricity as needed for war-munitions factories lacking!
That shipping channel of the Danube as needed by barge traffic transporting oil from the Romanian oil fields also at low-water level, this main "arterial route" not use-able in the ordinary sense.
Oil as pumped from the ground and available NOT reaching the refineries!
Those persons in the aftermath of the war compiling the American Strategic Bombing Survey [USSBS] were even aware of this? That is a question of which a devoted reader to the blog perhaps has the answer?
Consider this book by David Irving a biography rather than history? The original source documents the many dozens of diaries as kept by Milch during the war. Those thoughts and perceptions of the German military man NOT with hindsight most valuable to understanding how and why the war was fought as it was?