|
Influence of change of the external factors
on river
bed deformation
Evolution of river bed is
morphology change of a river channel and flood plain, constantly occurring
under action of the current water. Evolution of river bed is the external form
of movement bed load of the rivers. Now at significant antropogeneous
influence on an environment there are changes of the circuits of deformations
of the rivers. It results to unexpected and at times to destructive
consequences.
The type of river bed evolution
is the certain circuit of deformations of a river channel. Carrying a
researched site of the river to any type of channel process we can predict
possible deformations of this site of the river. It is very important to find the reasons of existence
various channels. In the State hydrological institute all types are built on
one determining axis: transport ability of flow.
In the
Moscow
State
University all
types of channel process are defined by other factor. This
mutual arrangement of level of a channel forming charge, mark flood plain and
middle bar level.
We offer to consider both these
channel forming factors – transport ability of flow and channel forming
discharge. Let's arrange transport ability on a vertical, and channel forming
discharge - on a horizontal.
The not ramified channels are
located in the first column of the table. In second -
ramified. Both of them are built on transport ability.
In first column are middle bar
type, side bar type, limited meandering and free meandering. In second column are middle bar type in ramified channel, side bar type in
ramified channel, cut-off meandering, free meandering in ramified channel.
Thus we
receive distribution of types channel process at once under two determining
factors. It gives us a key to the forecast of changes of types of a channel,
and then and opportunity of purposeful changes of rivers.
|
