The useful work that can be extracted from gravity here on earth is in tidal power harvesting.  The relative movement of the moon cyclically pulls on the enormous volume and mass of the seas.  Harvesting the tides would only very slightly slow down the rotation of the moon around the earth.

The useful work that can be extracted from gravity here on earth is in tidal power harvesting.  The relative movement of the moon cyclically pulls on the enormous volume and mass of the seas.  Harvesting the tides would only very slightly slow down the rotation of the moon around the earth.

sounds good, you have admitted that there is usefull energy from gravity.   

sounds good, you have admitted that there is usefull energy from gravity.   

My question did not involve how the water got into
a reservoir. The hydrology cycle takes care of that
very efficiently. Water recycling on earth is a given.

Water that falls into the great lakes region that passes
thru Niagra Falls moves from higher to lower elevations
by gravity other wise is would be static.

Water that falls into the City of New Orleans is static and moves from
lower elevation to higher elevation by a series of large pumps.

Obviously the water in New Orleans had no where to fall
but yet is was created by the same sun.

If a ball is dropped from a plane gravity crashes it to
the ground. If you pour a glass of water out of a plane
then the sun causes it to crash to the ground.

True. But the original question can gravity cause
energy generation is not being answered.
Why is it so hard to admit that gravity causes
water to fall when presented the opportunity.
With the hydrology cycle supplying the energy
it still does not prevent gravity causing the
water to fall.

The Incobrasa machine like the fraudulent claims of Wayne Travis purports to obtain energy from cyclically lifting and lowering weights.