Abstract:
Monitoring river water quality is very important for a riverine country like Bangladesh. In
the developed nations many agencies are involved in the continuous monitoring of the
water bodies including rivers and lakes. In Bangladesh, only lab testing procedures are
followed for assessing the water conditions. But this approach is both time-consuming and
expensive. Moreover, it is not possible every time to collect water samples from any point
and test immediately for the non-availability of laboratories. Remote sensing technique is
a new technology for monitoring water quality which is very time efficient and also costeffective. This study was undertaken by analyzing data from satellite images (Sentinel 2A)
and geographical information systems (GIS) to find the relationship between water quality
parameters, reflectance values and water indices of spectral images. The main purpose of
this research was to develop a model for the physical and chemical parameters of the
Dhaleshwari River in Savar. The water parameters used in this study are Acidity (pH), Total
Dissolved Solids (TDS), Total Suspended Solids (TSS), Dissolved Oxygen (DO), Color
and Turbidity. Samples from 10 points were collected and tested in the laboratory. At the
same time, satellite images (Sentinel 2-A) of the sample collection date were downloaded
and reflectance values were extracted from the satellite images. Finally, equations were
developed incorporating the reflectance values and lab test values only. There are few water
indices which are very useful in predicting the water bodies of an area. In the second part
of the study, few important indices were calculated and regression equations were
generated. Finally, equations with the highest regression values had been proposed to use
in this study. A positive strong correlation between calculated water indices from satellite
images and water parameters of the second day with 10 points helped to build some
regression equations. These models could be used to predict these six water parameters at
any point along the stream in Savar from the satellite image directly.
