IS2104: Atmosphere and Hydrosphere


April 18, 2010

Filed under: Uncategorized — 09ip01 @ 7:03 pm

In this lesson, we were introduced to the hydrological cycle and the drainage basin system.

The diagram below summarizes the hydrological cycle:

The hydrological cycle is considered a closed system as there are no inputs or outputs into and from the system.

The next diagram summarizes the drainage basin system:

Explanation if terms:

Evapotranspiration: Water lost through both evaporation and transpiration

Surface storage:

Precipitation which is retained temporarily at ground surface as interception by vegetation, or depression storage, such that it does not appear as infiltration or surface runoff during rainfall period of shortly after.

Percolation and infiltration:

Water infiltrates the soil by moving through the surface.

Percolation is the movement of water through the soil itself. Finally, as the water percolates into the deeper layers of the soil, it reaches ground water, which is water below the surface.


The lateral (horizontal) movement of water below the ground surface. When water permeates through the soil’s surface, gravity draws it downwards, and hence it will continue to flow until it reaches an underground river or lake.

Water Table:

The upper surface of this underground water is called the “water table”. Ground water can intersect with surface streams, it can appear at the surface as springs, and it flows generally downhill toward the ocean.

Lastly, this image roughly summarizes the hydrological cycle and the drainage basin system:

Sorry this is super late!

And click on the images to open in another window if they’re cut off k!

– Paveta

The next diagram shows a summary of the water cycle and the drainage basin system: