Four Types of Drainage Basin Stores
In this essay I intend to give brief descriptions on 4 types of
Drainage Basin Stores, and then explain how different human actions
can influence these. As explained in previous pieces of work, the
water system is made up of several stores and flows, one input
(precipitation), and 3 outputs (run-off, evaporation, transpiration).
The four main stores I am working on today are Interception, Soil,
Surface and Ground water.
Water will almost never land directly on a bare surface. Most
commonly, when rain is falling it will first hit vegetation – e.g. the
leaves on tree branches. The water can then be stored here. The term
for this process is interception – the water has been intercepted from
continuing through the hydrological cycle. However, the amount of
water that is intercepted relies on a number of factors:
* The Type of Vegetation – trees and grass would give very different
interception amounts due to being very different in structure.
* Precipitation Type – Snow, hail and rain have different
characteristics and behave very differently when concerning
interception and run-off.
* Precipitation Duration – different effects are produced by
prolonged rainfall and short showers.
* Precipitation Intensity – varied levels of rain produce
corresponding amounts of interception and run-off.
* Time of Year – each season has a different influence on the water
* Land Use – When concerning crops, different impacts on
interception can be found.
These are all natural factors which affect the Interception store, but
human factors can largely influence it as well. One example of this is
Urbanisation. This means that large area’s of land which were once
lush and green will become covered in impermeable surfaces such as
tarmac; any precipitation landing here will therefore not be
intercepted as there is no vegetation to do so. Another factor is
Deforestation. This is a growing concern in modern society as it is
happening at a rapid pace, and although actions have been taken to
redevelop forests etc we cannot possibly keep to the current rate.
Without trees, interception rates will dramatically decrease, perhaps
resulting in more flooding because the water will reach the rivers at
a much faster pace. And even if we do manage to replace every tree we
cut down with a new one, chances are it will be a different type of
tree. This may not seem like a big deal at first, but we know that
coniferous tress hold much lager amounts of water than deciduous ones
do, so once again, water will reach the river much quicker.
Not all of the water which lands on a tree will be stored however.
Some of it will take another path – a process called Through Fall.
This is when water drops off leaves through...