The human body has on average 10 pints of blood, or 2.5 gallons. The Connecticut River at Thompsonville has an average discharge of 483 cubic meters per second.
Now, let us consider the number of Native Americans killed by European settlers from 1492 to 1592, as a recent CNN article would have it. That number is estimated at 56 million.
The amount of blood one can lose before the heart stops beating varies, but the average is 2/3 of total blood volume. 56 million times 2.5 times 0.75 is 105 million. So 105 million gallons of blood. That is 397468.23732 cubic meters. Divided by 483, that is 822.915 seconds to drain all that blood, or 13.72 minutes.
So with the estimate given by CNN's article, the number of people killed by Spanish colonization gives us a volume of blood that equals the average flow of the Connecticut river for 14 minutes.
That is all an estimate, of course, and hardly considers the effect of English colonization. But it's a baseline. 14 minutes of blood river per 56 million dead, 14 more minutes per each additional 56 million. Higher estimates of the population of the western hemisphere have the death toll closer to 100 million, so that would be a bloody Connecticut river for nearly half an hour.
Hard to say! We will never know precisely how much this hemisphere lost.
Because the conquistadors burned most of the Aztecs and Mayan literature so it's hard to tell what kind of diplomatic relations these people had with lands beyond their own empires. I wrote an essay earlier here positing that the Spanish were ultimately better colonizers than the English because they let a lot of the remaining Indians live. I revise my assessment, based on what I have learned recently about the Conquistadores -- that they deliberately impeded the efforts of native political leaders to mitigate the spread of smallpox in their midst, including targeting the priesthood that would have coordinated an effective response.
With that in mind, I see little difference between the Spanish and the English colonization after all. Both groups were part of an alien invasion and the aliens won. I am now opposed to any further political influence from the Eastern Hemisphere.