erosion and sediment control works at dsi/turkey · erosion and sediment control works. at...

EROSION and

SEDIMENT CONTROL WORKSat DSI/TURKEY

İbrahim BİROĞLUForest

Engineer

[email protected]

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

A Branch

of Menderes River

Nazilli/Aydın1965

Ağlasun Stream

/ISPARTA 1963

İncirlikaya

Stream, ÇANKIRI 1959

Haldizen

Stream/Uzungol/TRABZON 2007

Karaçay Stream/ Osmaniye

Basin

of Kapulukaya

Dam Afforestation

Works

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