Lakes are versatile ecosystems and they are under the threat of eutrophication and siltation. The physical characteristics of a lake provide some insight into the status of the lake. Satellite imagery analysis now plays a prominent role in the quick assessment of characteristics of a lake system in a vast area.

Indian Remote Sensing Satellite (IRS P6–LISS-III) images are used for the prediction of depth, temperature, and turbidity. IRS images are superior to Landsat by way of quality and low cost. Depth and water temperature is related to the ratio of radiance in green and red bands while turbidity is related to the radiance from the green and MIR bands.

This study is an attempt to assess the water temperature, depth, and turbidity level of a lake system (Akkulam–Veli lake, Kerala, India) using IRS P6–LISS-III imagery. Field data were collected on the date of the overpass of the satellite. For the assessment of water temperature from satellite imagery, regression equation using spectral ratio (green/red bands) is found to yield superior results than the simple regression equation and multiple regression equation. Model performance can be increased by increasing the number of samplings stations. For predicting the water depth, radiance in green and red bands can be used whereas that for turbidity, radiance in green and SWIR can be used. IRS P6–LISS-III imagery can be effectively used for the assessment of the physical characteristics of a lake system at a low cost.

Highlights of the study are published by Sheela et al in the International Journal of Applied Earth Observation and Geoinformation