Monitoring of topographic change on the coastal area

kayakjokeMechanics

Feb 22, 2014 (3 years and 7 months ago)

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M
onitoring of topographic
change on the coastal area

Jinah

Eom
1,2
,
Jong
-
Kuk

Choi
1
,
Joo
-
Hyung

Ryu
1
,
Joong
-
Sun Won
2



1

Korea Ocean Satellite Center, Korea Ocean Research &
Development Institute (jina9003@kordi.re.kr)

2

Department of Earth System Sciences,
Yonsei

University

Contents


1.
Introduction & Objective


2.
Study area


4
. Results


5. Conclusion


3. Data & Method

1. Introduction

1. Introduction


Since

the

1980
’s,

a

series

of

construction

projects

for

land

reclamation

have

been

carried

out

on

a

large

scale

in

western

sea



Land

reclamation

combined

with

the

dynamics

of

tidal

currents

accelerated

local

sedimentation

and

erosion,

resulting

in

the

fast

reformation

of

intertidal

topography


For

this

reason,

Lee

et

al

(
2006
),

Ryu

et

al

(
2008
),

and

so

on

were

carried

out

monitoring

of

tidal

flat

topography

using

Digital

Elevation

Model



(Lee et al, 2011)

1. Introduction


The

Nakdong

River

Estuary

Barrage

(NREB)

was

constructed

in

1987

to

prevent

saltwater

intrusion

and

to

provide

the

sustainable

water

supply

in

the

upstream

channel

of

the

NREB
.


Fluvial

changes

and

sedimentation

problems

have

been

continued

due

to

urbanization

and

development

in

the

watershed

as

well

as

construction

and

management

(sediment

dredging)

of

the

NREB


1. Introduction

1. Introduction


The

importance

of

the

east

sea

to

key

industries,

such

as

nuclear

power

plants,

shipyards,

and

cement

production,

and

to

a

lesser

extent

the

fishing

and

leisure

industries,

is

gradually

increasing



However,

coastal

erosion

in

east

sea

is

being

accelerated

so

that

the

size

of

the

sandy

beach

is

being

reduced

abruptly

along

with

a

lots

of

other

places

including

Jugbyeon
,

Bongpyeong

beach,

Sanpo
-
ri
,

Weonnam
,

Osan
,

Deogsin
,

and

Hupo

in

Uljin
-
gun
.



Objective

Long
-
term
monitoring
using
remotely
sensed data


Observed a
topography

through
survey

Propose integrated
management
methods for the
utilization and
preservation of
coastal seas in the
near future

Final goal

In this study

2. Study area

3. Data


Remotely sensed data


Change of sandbar : used
Landsat

ETM+ image from
2002 to 2010


Monitoring of shoreline change : used aerial photograph,
IKONOS, KOMPSAT
-
1/2 from 1971 to 2009


Monitoring of topography : used aerial
LiDAR

data and
terrestrial
LiDAR

at 2008, 2010


In situ data


used DGPS


Date : May. 2008., Jun. 2010


For comparison with
Lidar

data

Location of 2
nd

grade measurement survey benchmarks
within KORDI
-
ESRI

Method

extract line


Extracted shoreline and
sandbar


estimate the reflectance of
sand and sea


dry sand reflectance is
very strong


Near 750 nm : sea is
absorption but sand is
reflectance


Sea is dark color but
sand is bright color



used

NIR band

Method


LiDAR

DEM


LiDAR



generated DEM data



DEM
change

= DEM
2008



DEM
2010



DEM
change

: topographical change

DEM
2008
: topographical height in 2008

DEM
2010
: topographical height in 2010


Positive : represents erosion

Negative : sedimentation


Results 1
-

sandbar



Nakdong

River

Estuary

Barrage

(NREB)

was

constructed

in

1987



After

that,

current

rate

and

sedimentation

rate

were

changed




Nakdong

river

is

a

major

source

of

sedimentation

of

sandbar



Tide height

2003.11.02 : 68 cm

2010.11.05 : 71 cm