Abstract:
The dynamics of coastal ecosystem are mainly controlled by nearshore processes,
coastal geomorphology and human induced land-use changes. A rapid change of
coastal shoreline due to harbour construction in Oluvil, which is in Ampara district
caused a serious coastal erosion scenario. This study examines the coastal
microtopography in relation to high resolution digital elevation models, coastal
vegetation bioshield mass, and sea level rise. A Kite Aerial Photography (KAP) platform
was created using two light-weight automatic cameras with dual bandpass Red-NIR
filters, a Picavet stabilizing rig, a GPS tracker and a parafoil kite. The KAP images with
high resolution were acquired at 15 m altitude and the data was processed to build
mosaic images, orthorectified and georeferenced DEMS using Agisoft PhotoScan
(structure-from-motion) and ENVI software. Oluvil beach habitat vulnerabilities were
mapped using Normalized Difference Vegetation Index (NDVI) for vegetation bioshield
mass estimation, Digital Elevation Model for sea level rise and coastal land-use
changes using historical images. The image processing produced a point cloud with an
average density of 20 points/cm2; a DEM with 2 cm resolution; and an orthophoto
mosaic with an average resolution of 0.5 cm. The NDVI and historical images showed a
significant vegetation reduction over time. With subsequent negative impacts of coastal
vulnerability such as flooding due to sea level rise. The objective of this study is to
assess the vulnerabilities in Oluvil coastal beach habitats in terms of coastal erosion,
sea level rise and vegetation biosheild mass and health. This work utilized KAP which
has a great potential to bridge science with high spatial/temporal resolution in-situ data
for monitoring coastal habitat vulnerabilities, and can be used for sustainable land
management prior to implement any development or construction program.
