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Presentation On
Stream Action
By__
SAIDA ISLAM SEJUTI
Roll- 18103432
Reg. no- 6829
1st
Year, 2nd
Semester
Department of Environmental
Science and Engineering

Outline of the Presentation
Concept of Stream Action
Water on Earth, Running Water
Drainage Basins, Drainage Patterns
Factor Affecting Stream, Stream Erosion
Floods, Lakes; the Life Cycle of Lakes

Concept of Stream Action
Steam Action= Stream + Action
Stream:
A flow of water in a channel or bed, as a brook, rivulet,
or small river.
Action: Activity, work, movement, effort and such more.
Comprises– The activity or movement of the flowing water.
There origin, cause ,effects, affects, way etc and so on.
Great oceanic Stream Flow

Stream
Action
Water on
Earth
Running
Water
Drainage
Basins
Drainage
Patterns
Affectin
g Factors
Stream
Erosion
Floods
Lakes
Concept of Stream Action

Water on Earth
71% of earth's
surface is covered of
Water
3%
Freshwater
2%
reserved in Glaciers,
icecaps etc.
Less than 1%
is in earth's surface.
97%
Salline water
In Oceans
Volume, Types & Location :
Vapor

Larger Distribution:
Water on Earth

Water State and Cycle:
Water on Earth
Glacier
Liquid

Running Water
 The most powerful agent
of erosion.
 Continents are eroded
primarily by running water
at an average rate of
1 inch every 750 years.

Can carry these weathered rock
pieces in three different ways:
Solution: The smallest particles,
minerals.
Suspension: Sand, silt & clay
Bed load: Large sand grains,
pebbles, and boulders, are even
heavier rock particles. they just get
pushed along the bottom as the bed
load of the river.
Running Water

Rocks carried in running Water
Changes—
Abrasion is the grinding action;
changes particles in smaller, smother or
in rounded shapes over time.
Running Water

Is a place where water collects and then flows into a
conventional outlet like a bay or a river.
Encompasses the surface water and the groundwater.
Numerous river branches collect water from different
sources and then flows into the mainstream
Drainage Basins

Drainage Basins
Main 3 types of Drainage Basins—
Ocean Basins—
The largests are(% of world’s land)
Atlantic Ocean: 48.7%
Arctic Ocean: 17%
Pacific Ocean: 13%
Indian Ocean: 13%
Southern Ocean: 8%

River Basins—
5 largests are- (in M km2)
Amazon-7
Congo-4
The Nile-3.4
Rio De La Plata-3.2
Mississippi-3
Drainage Basins

Endorheic Drainage Basins—
• Are inland basins that do not drain to an ocean.
• 18% drains to endorheic lakes or seas or sinks.
• The largest of these are-
Caspian Sea, Aral Sea, Okavango river etc
Drainage Basins

Drainage Patterns
Created by stream erosion over time.
Reveals characteristics of the kind of rocks and geologic structures.
Formed by the streams, rivers, and lakes in a particular drainage basin.
Governed by the topography of the land, whether a particular region.
Dominated by hard or soft rocks, and the gradient of the land.
Some common
Patterns are--
Dendritic (Most common)
Develops--areas where the rock (or
unconsolidated material) beneath the stream
has no particular fabric or structure .
Radial
Volcanoes usually display excellent radial drainage
commonly develops are domes and laccoliths.
Trellis
Typically develop where sedimentary
rocks have been folded or tilted
Rectangular
Develop in areas that have very little topography
and a system of bedding planes, fractures, or faults
Parallel
Develops in regions of parallel, elongate
landforms like outcropping resistant rock bands.

Factor Affecting Stream
Factors Affecting Velocity:
Gradient (Slope)- Stream Profile
•Steeper gradients promote higher velocities.
•Head waters(Steeper) & Base levels
Channel Characteristics
•Shape, Size & Roughness(materials) etc.
Discharge (Volumetric Measure of Flow)
•Q=VA (average velocity x cross sectional area)

Factors Affecting Volume:
1- Weather or Climate
2- Seasonal Changes
3- Merging Tributaries
4- Human Impacts etc.
Factor Affecting Stream

Stream Erosion
Stream water is a very important agent of erosion.
It can erode rocks and soil.
Dissolves minerals from rocks that causes Chemical
erosions gradually.
By great gravitational forces it creates smaller sediment
particles, transports them & causes Physical erosions.
It is also affected by--the velocity, or speed, of the water.
 3main processes of Stream Erosions are— # Solution, #
Suspension & # Bed Load
The river Erosion of the Grand Canyon.

Hydraulic Action
Causes of Stream Erosions-
Hydraulic Action: When the velocity of the water and steepness of
the land is greater and also when the bottom of the water’s surface is
rough.
Abrasion: Happens by the friction from the constantlymoving rock
fragments, sediment, and gravel in the water.
Attrition: Typically happens on upstream, when the velocity of the
river is higher.
Helps the sediment to be carried faster.
Stream Erosion

Extreme Flood state in Japan
Causes–
# Rains
# River overflow
# Strong winds in
coastal areas # Dam
breaking
# Ice and snow-melts
etc
Floods

Types (mainly 2)—
 Flash Flood: Flash flood
is a rapid flooding of
geomorphic low lying areas:
washes, rivers, dry lakes &
basins.
&
Costal Flood: Coastal
flooding occurs when
normally dry, low- lying
land is flooded by sea water.
Floods

Lakes
Is a body of water that is surrounded by land.
Vary greatly in size, shape, origin, waters type etc.
Some most common types are-- #Tectonic, # Volcanic,
#Glacial, #River, #Wind-made, #Man-made lakes etc.
Water sources- snow, melting ice, streams, and groundwater.
 Most lakes contain freshwater.
Largest lake—Caspian (370,000+
s km)
Deepest lake-- Lake Baikal (2 km
Highest Lake-- Lake Titicaca
(3,810 m MSL)
Lowest Lake-- Dead Sea (395 m
below SL)
Caspian Lake’s View

Life Cycle of Lakes
Oligotrophic
Mesotrophic
Eutrophic
As per Scientists saying The Life
Cycle of Lakes can be described
under 3 inter-connected
classes---

plants and
algae
slowly die
warm, shallow
water ;causes
plants , algae
to decompose
Dust and
mineral
deposits on
the bottom
Rain washes
soil and
pebbles into
the basin
remains of
fish, animals
pile up on the
lake’s bottom
The lake
becomes
smaller
becomes a
marsh, bog,
or swamp
drying-up
process slows
down
dramatically
the lake
becomes
dry land.
Life
Cycle of
Lakes

Conclusion
Stream Action Undoubtedly includes all water bodies and actions related
to them. So, all of these topics we discussed here are really a tiny part of
them.
But though in these slides we have got little or more the
concepts of Water bodies of the world, there types of flow, drainage
basins, pattern ,erosions caused by Streams, affecting factors of it,
floods, lakes etc.
We have also learned about 2 cycles here.

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