TITLE:
Bathymetric and Geochemical Analysis of Lake Al-Saad, Abha, Kingdom of Saudi Arabia Using Geoinformatics Technology
AUTHORS:
Javed Mallick, Mohd Abul Hasan, Yasser Alashker, Mohd Ahmed
KEYWORDS:
Geochemical Water Properties, Bathymetry, Worldview-2 Data, Remote Sensing and GIS
JOURNAL NAME:
Journal of Geographic Information System,
Vol.6 No.5,
October
6,
2014
ABSTRACT: This study investigates
the potential for remote sensing of lake water bathymetry and geochemical by 1)
examining the empirical based technique for retrieving depth information from
passive optical image worldview-2 satellite data, 2) performing atmospheric
correction, 3) assessing the accuracy of spectrally based depth retrieval under
field condition via field measurement, 4) producing bathometry and geochemistry
mapping by examining spectral variations for identifying pairs of wavelengths
that produce strong linear correlation coefficient between the band ratio. The
results indicate that optical remote sensing of bathymetry and geochemical
investigation is not only feasible but more accurate under conditions of
typical lake water, supporting field survey. The Pearson correlation matrix (R)
between the examined water samples/depth and the TOA reflectance values of the
worldview-2 (WV-2) satellite data have been investigated and found good
correlation. The models developed using the combination of different band pairs
also show high accuracy. Cartographical maps were generated depending on the
linear correlation coefficient between the measured parameters and the TOA
reflectance values of the worldview-2 data. The investigation shows that
dissolved oxygen (DO) of the lake water is slight lower than the permissible
limit of Saudi standards for lake water. The shallow water has high DO
concentration, whereas the deeper shows significantly lower down. Electrical
conductivity measurements serve as a useful indicator of the degree of
mineralization in the water sample. All the samples which have EC exceed limit.
The spatial distribution of EC and TDS inferred that the EC and TDS
concentration is the highest at the eastern part of the lake whereas
concentration drops down towards the southern side. This study confirms that
remote sensing incorporated with GIS and GPS could afford an integrated scheme
for mapping water quality and bathometry of the surface water.