Monitoring of topographic change on the coastal area

Jinah Eom1,2, Jong-Kuk Choi1, Joo-Hyung Ryu1, Joong-Sun Won2

 1 Korea Ocean Satellite Center, Korea Ocean Research & Develop-

ment 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 cur-rents accelerated local sedi-mentation and erosion, result-ing in the fast reformation of in-tertidal 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 intru-sion 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 con-struction 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 acceler-ated so that the size of the sandy beach is being re-duced abruptly along with a lots of other places includ-ing Jugbyeon, Bongpyeong beach, Sanpo-ri, Weonnam, Osan, Deogsin, and Hupo in Uljin-gun.

Objective

Long-term monitoring using re-motely

sensed data

Observed a topography through sur-

vey

Propose integrated management meth-

ods 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 2nd grade measurement survey benchmarks within KORDI-ESRI

Method –extract lineExtracted shoreline

and sandbar estimate the reflectance of

sand and sea dry sand reflectance is

very strong Near 750 nm : sea is ab-

sorption but sand is re-flectance

Sea is dark color but sand is bright color

used NIR band

Method – LiDAR DEM

LiDAR – generated DEM data

DEMchange = DEM2008 – DEM2010

DEMchange : topographical changeDEM2008 : topographical height in 2008DEM2010 : topographical height in 2010

Positive : represents erosionNegative : 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