|– Surface water evaporates from land,
lakes, rivers, oceans. Evaporated water is nearly pure, the ions
– As water evaporates and turns to vapor
it rises in the atmosphere, cools and forms clouds. The hotter the
air, the more vapor can be held.
– At some point vapor reaches saturation
and then begins to condense (reaches the dew point) around a little dust
mote of some kind (called condensation nuclei) and a drop of water forms.
If it is very cold, it will be ice.
– It begins to fall and it usually hits
rising warmer air and evaporates before hitting the ground. The rest is
precipitation as rain, sleet or snow.
– If it doesn't melt and evaporate, it
may also be swept up by rising air, and can go up and down several times
forming hail and when it is large enough in finally fall all the way to
- When water falls it either evaporates,
trickles down into the soil or it moves overland until it reaches the ocean.
The mid continental divide determines whether the water goes into the Pacific
or the Atlantic.
– In Wisconsin, there is a mid-mid continental
divide at Sunnyslope road (going west on I-94) that determines if the water
is going to eventually drain into the Mississippi and into the gulf, or
into the Atlantic ocean. By law, all water removed east of Sunnyslope
is supposed to go back into the "watershed" of lake Michigan and all water
west into the Mississippi watershed. This has caused a lot of wrangling
between Milwaukee county sewage district and Waukesha county.