You make some worthy points, my estimate of 25% void volume is probably too high, it may be closer to 10%. There should be ways of doing the math, but none occur to me at the moment.

The idea as I'd first thought of it was when watching a documentary on ancient Egypt, and how variable the floods were. They came yearly, like clockwork, but there was an optimum height, and anything much less and there'd be famine, and much more they'd have property damage, so they built a flood-meter for the Nile to help the pharaoh make plans. The program said about one year in seven was too low to ensure enough food for the people.

So let's take those two numbers and recalculate the rainfall needed that seventh year.

The 10% figure effectively multiplies the annual rainfall by 10x in storage height, and let's say they used it once every seven years (storing six). That's be (46m/10*6) or about two feet per year of rainfall collected. It was a wetter climate back then, the Giza Plateau was covered with vegetation and had a creek flowing through the area. But it was getting noticeably drier (in the time scale of pharoahs' dynasties).

Why not a flat roof? Good question, but we have sump pumps these days that can pump water 150 feet, from the bottom of a well, up. As you correctly point out, a suction pump only works 10meters (usually less). The reservoir was about 150 feet deep. They needed a means of pumping the water out of the reservoir. That's what I think the "King's" and "Queen's" Chambers were. I think the "sarcophagus" that was too short for a fully-grown man was actually a firebox, intended to heat the granite slabs above it to high temperatures, and that water would be introduced into the King's Chamber (by means TBD), and would flash-boil to steam, which would be driven into the Queen's Chamber, forcing the water between the two chambers (in the Grand Gallery) up and out of the Great Pyramid.

Supporting this I have two factoids, not quite compelling, but interesting.

When investigating the granite slabs above the "sarcophagus" (the bottom one of which was cracked and plastered by hand), investigators found black material of unknown origin which they postulated was probably insect remains. I think they should've done a more rigorous analysis of that material, I think it was ash from the wood burned in the granite firebox ("sarcophagus").

The other piece of the mystery is that the "air shafts" aren't at the same angle, and the longer one exits the pyramid lower than the shorter one, and has a bend in it, as if it were originally intended to exit at the same height. When you take physics, they describe hydrostatics before they describe hydrodynamics. According to hydrostatics, you'd have the same hydrostatic head (pressure) in the two "air shafts" if they both started at the King's Chamber and exited the Pyramid at the same height, so flow should be equal for both airshafts, right? That'd be true (approximately) for slow-flowing water, but once you build up a hot steam bubble behind a big column of water, it doesn't flow slowly, and you have to take the resistance of the pipe into consideration in order to keep the flow equal in the two "air vents". I think they designed it originally based on hydrostatic assumptions, then mid-construction ran a test and discovered hydrodynamics, and lowered the outlet of the longer "air vent" to compensate for the greater hydrodynamic backpressure.

It's interesting to me that one "air shaft goes east toward the known cropland/floodplain, but the other goes west, to land that wasn't known to be farmed, Maybe the point of the Great Pyramid was to double the land available for growing crops, as well as providing insurance against those seven-year droughts.

So as I see it, it was either a masterpiece of engineering that served a real purpose, stabilizing an empire's source of food and drinking water, or it was a collosal yet cr@ppy tomb constructed for the sake of the ego of the pharaoh.

Anyone have a third option?

wcelliott, It was a colossal, but NOT cr@ppy tomb constructed for the sake of the ego of the pharaoh. There is not one scrap of evidence pointing to its use as a reservoir or water storage facility. Your "factoids" do not hold up to scientific scrutiny and if the sarcophagus was really a firebox, as you claim, it would still show tell-tale marks. Also, granite of that thickness would crack with the intense heat of a fire within it and that size of a "firebox" would be totally inadequate to heat even the small volume of water within the chamber. I have never seen a more "crackpot" hypothesis, (pun intended!) (())