Optimization of field spectroscopy and Hyperion data to evaluate water quality in the Shenandoah River Basin, Virginia

Abstract:

Several studies have demonstrated the importance of Hyperspectral remote sensing in monitoring the spatial variation of optical water quality parameters in lakes, rivers and oceans. A multiband quasi analytical algorithm is used to estimate the inherent optical properties of water, and the Bio-optical model based tool is also used to estimate water quality and bottom properties from remote sensing images for chlorophyll a, colored dissolved organic matter, and total suspended sediments concentrations across the Shenandoah River basin using EO-1, Hyperion data and field spectroscopy. Preliminary results show that Chl a concentrations compared with values reported for coastal and inland waters around the world are high in the Shenandoah River with values varying from 0.001 - 12.636 μg/l, with an average concentration of 9.67 μg/l. Total suspended sediment concentration values are in good agreement with the TSS concentrations measured on the field with a range of 0.001 - 3.0227 mg l-1, and, an average concentration of 0.266 mg l-.1. CDOM concentration varies from 0.001 - 0.4 μg/l, with average values of 0.13 and 0.15 μg/l for the South Fork section of the River. Our results also suggests that, the river is dominated by high CDOM absorption, high Chl a concentrations and abnormally high reflection in the red, probably caused by the high concentrations of red clays found in the river since CDOM is a mixture of compounds of terrestrial and marine origins. To validate the performance of our analysis, we used; error, bias and root mean square, and obtained 0.0697 μg/l, 0.0048 μg/l and 0.0174 μg/l respectively, for the River Basin show that the data had sufficient sensitivity to detect optical water quality concentrations.

Key words: Hyperion, field spectroscopy, inherent optical properties, Bio-optical model Shenandoah River, water quality, chlorophyll a, colored dissolved organic matter, and total suspended sediments.