hydrology

Water is unevenly distributed across the globe. 97% of the world's water is in the ocean. 2.5% of the world's water is fresh and about half of this is unavailable to the hydrological cycle because it is stored in glaciers and deep ground water. Mobile fresh water occurs as vapour, precipitation,stream water etc. This accounts for about 0.3% of the world's water and is the focus of the hydrology.

The hydrological cycle is the continuous movement and storage of this water. There are atmospheric and terrestrial components to the hydrological cycle and vegetation interception (where water does not reach the ground) and other such phenomena are important parts of the hydrological cycle.

Ground water

Water that comes into contact with the ground may;

1 remain on the surface as pools and evaporate after a short time

2 flow in rivers or as overland flow and will eventually evaporate back into the atmosphere from          rivers, lakes and other pools and accumulations of surface water. It may also flow into the sea or become ground water.

3 or infiltrate into the soil to form soil moisture which may evaporate (as opposed to ground water       which is too deep to be affected by evaporation) or move to streams as through flow. This water may also percolate downwards and become ground water where it will remain for long periods of time where it moves slowly upward by capillary action until it can be evaporated back into the atmosphere.

The hydrological cycle is not always complete but is usually shortcut and thus becomes more complex. More Later...