erosion and sediment control works at dsi/turkey · erosion and sediment control works. at...
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EROSION and
SEDIMENT CONTROL WORKSat DSI/TURKEY
İbrahim BİROĞLUForest
Engineer
General Directorate
of State
Hydraulıc
WorksInvestigation
and Planning DepartmentErosion and Sediment Control SectionYucetepe
06100 Ankara, Turkey
Turkey
area neither have uniform geography nor climate, has 7 different geographical regions
with different climatic condition.
Average altitude is more than 1000 meters. She has more than
9000 plant species of which about 3000
are endemic.Also
Turkey
is hydrologically
divided
into
25 drainage
basins, the
rivers
generally
irregular
regimes.
Erodible
Lands
in Turkey
In addition to bed load, approximately 500 million tons
of suspended sediment are transported by stream and rivers
(EIE).
According
to
the
inventory
studies
% 86
of the
country
has been
exposed
to
water
and
wind
erosion
different
level
and
times.
There
is a natural
balance
among
vegetation, soil
and
run
off,
one
of them
easily
affectted
is vegetative
cover. When
the
vegetative
cover
is damaged, the
amount
of surface
run
off
increase
whith
the
result
erosion
are
formed.
Damages
of Erosion
and
SedimentErosion
is a serious
problem in Turkey, its
causes
social, economical
and
enviromental
problems.In
general flood
have
always
carried
comperatively
large
amount
of sediment to
the
main
streams. Erosion
and
sediment;
Damaged cities,
Çamlıhemşin-RİZE The
same
area, 10 minutes
later, August
2005
Ruined agricultural areas,
Damaged roads,
Ruined flood control structures,
Silting of reservoirs and harbors,
Damaged irrigation channel andcontaminated water.
Among the duties of DSI
is “to construct and operate protective structure against flood water
”
The investigation and application studies were began by DSİ
,Erosion and Sediment Control Section, to
control erosion and sediment in 1958
EROSION and
SEDIMENT CONTROL WORKS at DSI/TURKEY
Erosion and Sediment Control Section
duties
is to make studies at primary investigation and planning levels with the river drainage basin in order to prevent
the
damages
of flood and sediment, to evaluate this studies, prepare project report and to propose to implementation programs.
DSI has qualified
especially
on river
bed
erosion
and
channel
improvement.
DSI
also
seeks, in general , the
cooperation
of Ministry
of Environment
and
Forestry
in arranging, improving
and
rehabilitation
upstream
basins
of tributaries, forest, pastures, and
high
slope
agricultural
lands.
The erosion and sediment control activities are presently
carried out by settled priorities which are
Protection of residential areas,
Protection of public facilities,
Protection of reservoirs of dams,
Protection of agricultural fields.
There
are
two
ways
for
erosion
and
sediment control
in stream
basin;One
is to
carry
out
erosion
and
sediment control
measures
in stream
basin, The
other
is to
construct
some
structures
to
store
and
deposite
sediment.The
effective
way
is to
prevent
erosion
and
sediment in stream
basin, construction
soil
saving
dams
aren’t
a permanently
measure.
EROSION and
SEDIMENT CONTROL MEASURES
Erosion and sediment control section has carried out some structural and land treatment
measures, which are as follows
Land Treatment
Measures;
Main
porpose
of these
measures
is to
gain
ruined
nature
balance. Measures
are
change
according
to
land
use
capability.
Measures
for
Agriculturel
Area;
Contour
farming,Strip cropping,Cover planted area with mulch, brush, straw
or other suitable materials,Crop
rotation,Some
terraces,Proper use,
Measures
for
Forest
Area;
Constructing
a system of terraces, having protected outlet and drops,Planting the eroded area to some form of vegetation,Afforestation
with terraces on devastated hillside,Protecting, arranging, improving
and
rehabilitating
forest.
Measures
for
Pasture
Area;
Rotation
grazing,Range improvement measures,Deferred grazing,Range seeding,Protecting
pasture,Proper
use.
Reclamation
of Gully
and
Stream:
Preventing
erosion
and
sediment movement
in stream
and
gully
is required
to
establish
the
balance
between
water
abrasion
and
stream
bad
resistance.
Protecting
Gully
Erosion
by
Vegetation
:
If
protective
vegetation
cover
dosn’t
improve
and
can’t
prevent
gully
erosion. Vegetative
cover
will
carry
out
with
artifically. For
this
aim
fast
growing
local
trees
and
brushes
are
used.
One
way
of gaining
this
result
is to
lower
stream
bed
slope
thus
decrease
water
velocities
and
power. Also
the
other
way
is to
increase
the
stream
bed
force
by
some
structures.
Structures
constracted
vertical
in stream
bed
to
lower
slope
are
called
the
vertical
structures.
Structural Measures:
Establishing
the
balance
between
water
abrasion
and
stream
bed
resistance
to
prevent
water
erosion.
Structures
of increasing
stream
bed
force
are
a variety
of
pavementes
and
lateral
structures. These
structures
are
generally
used
in down
stream. Up
and
down
stream
basin
works
are
different
but completed
each
other.Erosion
and
sediment control
section
has been
carried
out
some
structural
measures
,which
are
follow.
Check Dams:
The
most
effective
structure
used
in stream
reclaimation
is check
dam.
Confused
with
soil
saving
dam, check
dams
main
purpose
is to
prevent
stream
bed, bank erosion
and
control
the
land
slide.
In
addition
the
main
function
of check
dams,To
collect
and
store
some
sediment goes
down,To
hold
the
sediment suitable
place, To
prevent
the
structures
above
its,To
lower
the
bed
slope
given
distance
.
Soil
saving
dams
primary
purpose
is to
collect
and
store
sediment and
depris
in streams
or
gully.
Soil
Saving
Dams:If
the
sediment generated
in watersheed
can’t
be controlled, It
is thoughted
that
deposited
sediment and
debris, for
this
purpose
constructed
structures
is called
soil
saving
dams.
Soil
saving
dams
are
usually
larger
structures
than
check
dams, important
element in their
location
is the
presence of a large
storage
basin
above
them.
Cross-Checks:
If
natural
or
artificial
stream
don’t
have
sediment problem but having
abrasion
in theirs
bed. Cross
check
is consturacted
to
decrease
the
chanel
slope
to
prevent
stream
bed
erosion.
Construct retaining wall andreventment along stream toprevent erosion of bank . Also in flood channel to confine the flow.
Construct vegetative living of both bank to stabilization dikes.
As we
all
know
, combatting
erosion
and
land
degradation
requires
a lot of funds
and
commitment. It
is not possible
for
any
organization
, governmental
or
non
governmental
to
solve
with
the
problem alone.
Combatting
soil
erosion
and
land
degradation
is closely
link socio-economic
structure. Thus
without
people’s
commitment
and
participation, it isn’t
possible
to
implement
any
programme
or
policy.
In
conclusion
our
aims
are
to
reduce
the
movement
of damaging
amount
of sediment and
prevent
erosion.
SOME PHOTOS OF EROSION AND SEDIMENT CONTROL WORKS
AND AFFORESTATION
Şerabat
Stream
Nazilli /AYDIN/TURKEY1963 1965
1977 1987
1968
1982
A Branch
of Menderes River
Nazilli/Aydın1965
1969
1984
Ağlasun Stream
/ISPARTA 1963
1965
1968
İncirlikaya
Stream, ÇANKIRI 1959
1961
1975
Haldizen
Stream/Uzungol/TRABZON 2007
Karaçay Stream/ Osmaniye
Basin
of Kapulukaya
Dam Afforestation
Works