"Calif Bill" wrote in message
ink.net...

"Gould 0738" wrote in message
...
I would have agreed with the width/length of the tank/dam doesn't matter
...
but ... then why are dams so thick at the top? Dams can be 20 / 30 / ...
feet thick at the top where the water is only a few inches deep. There
is
more to this than me thinks!


Many dams have a service road across the top, a place to stage heavy
equipment
if need be for repairs, etc. That will require a certain practical width.
You
also need some structural mass to frame spillway gates, etc- often
located
near
the top of the dam. Hoover Dam has a highway across the top, and so is
probably
75 feet "thick" many feet above the surface. :-)


And parts of the dam are hollow.

Because a solid mass is not necessarily the most efficient use of material
WRT strength. (like a roof truss)

Inspection galleys, equipment areas, and
there are also waves hitting the top above normal water level. These have
a
side force.