IMPACTS OF EROSION

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22 Φεβ 2014 (πριν από 3 χρόνια και 3 μήνες)

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IMPACTS OF EROSION
AND SEDIMENTATION

MWIINGA KALONGA

GRADE 11 GEOGRAPHY

19
TH

APRIL, 2007.

OVERVIEW


A.
EROSION

-

is the process by which land surface is
worn away by the action of water, wind,
ice and gravity



Water, wind, ice & gravity produce various erosion features.



When rain falls, soil gets easily washed away.


Above: land safe from erosion.

Below: land vulnerable to erosion



Farming loosens soil and it becomes vulnerable to erosion agents


EXPECTED EROSION RATES
(TONS/ACRES PER YEAR)
FOREST LAND
FARM LAND
CONSTRUCTION
B. SEDIMENTATION

-
Sedimentation is the process by which the
eroded material is transported and
deposited by:



Water


Wind


Ice


Gravity



Water without sediments remains clear.



Sediments turn water into brown.

IMPACTS


Raindrop bombards, devastates and loosens soil particles.


Vegetation intercepts and minimizes raindrop impact on soil.



Lake filled up with sediments.






Sediments choke fish, which eventually die.

Sediments block drainage systems which may result in flooding.


Reservoir for storm management choked with sediments.

TASK FOR THE DAY


ASSIGNMENT

TASK1: Pupils to assess the impact of soil
erosion and sedimentation on the


Environmental and Economical


aspects in their communities


(pupils to be in groups)

TASK2: Pupils to present their findings

TASK3: Pupils to debate/discuss on their


findings