enigma already pointed out a serious flaw in your calculations - if the water was 'in orbit' at ~>1500 miles above the surface of the Earth, how did it lose its delta v? To take his question one step further, if that mass of water moving at orbital speeds (wrt the surface of the Earth) 'fell' to Earth, and the kinetic energy were converted to heat (where else would it go?), don't you think it would sterilize all living things on the surface of the Earth?
I also hinted at a far more serious flaw - "other than at the equator, write some equations giving the motion of the water, with specific reference to circular orbits". From your first post
so you clearly assume that all this water is in orbit and rotating about an axis (which?). Now all orbits around the Earth must have the Earth's centre as a focus - so any orbit other than at the equator will be at an angle to the equator, which means that a blob of water will pass through the equatorial band of water twice every orbit ... if you know of a set of orbits for a liquid hollow sphere that are stable (around the Earth), do let us know ... otherwise your idea contains a fatal flaw (if you don't understand this, please read a book on elementary celestial mechanics and then come back and we can have a proper discussion).