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This study aims to monitor and analyze the topographic changes in the coastal area, specifically focusing on land reclamation projects, Nakdong River Estuary Barrage, and coastal erosion. Various data sources such as remotely sensed data, aerial photographs, LiDAR data, and in-situ measurements were utilized to assess the changes over time. The results provide insights into the impact of human activities and natural processes on the coastal landscape.
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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 & Development Institute (jina9003@kordi.re.kr) 2 Department of Earth System Sciences, Yonsei University
Contents 1. Introduction & Objective 2. Study area 3. Data & Method 4. Results 5. Conclusion
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 • 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 In this study Final goal
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 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 DEMchange = DEM2008 – DEM2010 DEMchange: topographical change DEM2008 : topographical height in 2008 DEM2010 : 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