Investigating water quality of an urban water body using ground and space observations

Satellite based water quality monitoring and assessment is a thrust area of research. Present study focuses on use of space observations and ground data for assessment of spatial pattern in water quality parameters of an urban water body in Gorakhpur city of Uttar Pradesh, India. Water quality parameters namely, pH, Total Dissolved Solid, Turbidity, Total Hardness, Dissolved Oxygen and Biological Oxygen Demand were measured from the spatially distributed samples collected from the lake. Multiple linear regression models were developed using Landsat-8 OLI data and water quality sampling data to estimate the spatial patterns. It was observed that all the water quality parameters are significantly correlated with the radiance values of the Landsat-8 OLI sensor. Results of the regression model indicate a good agreement between the measured and estimated value of all the water quality parameters i.e., 82%, 70%, 90%, 66%, 84% and 79% respectively. Also, water quality maps when validated with lab tested value showed 71%, 62%, 71%, 55%, 75% and 86% accuracy. This study provides an effective and quick approach for mapping and planning of surface water (Lake) in urban areas with acceptable level of accuracy.