> As far as I knew last night, the Dead Sea was the only lake which
> does not drain: it maintains its level because evaporation is
> matched by entering water quantities. So does Salton Sea also
> evaporate? Are there any others?
There may have been a lot of salt in the ground there before the river
was diverted, from the evaporation of a preexisting lake. The water
from the river almost certainly brought in even more salt, and as the
water evaporates (as water tends to do), the salinity continues to
increase. This would be the case even if it did drain, though in that
case the lake would probably be empty before evaporation caused a
significant rise in salinity.
Mono Lake, just east of Yosemite National Park, does not drain.
Because it loses water (but not salt) only through evaporation, it has
an unusually high salinity even though all of its sources deliver
fresh water (which does contain a small amount of salt).
Not only does Mono Lake not drain underground, but it is actually fed
by fresh water springs. I can't remember whether there are rivers
flowing into it also. The springs are visible, as is the thin layer
of fresh water on the surface of the lake, due to the different index
of refraction of the fresh and salt water. If you stick your finger
into the lake, you can see two reflections -- one on the
fresh-water/air boundary, and one on the salt-water/fresh-water
boundary. If you stir it up, you can watch the swirling turbulance.
There are guided kayak tours of Mono Lake. Lots of fun, and highly
educational. I think they're always in the morning, due to strong
afternoon winds.