This research presents a novel approach of using open data multispectral imagery as indicators Normalized Difference Vegetation Index, Land Surface Temperature (LST), Green-Shortwave Infrared index and Soil Adjusted Vegetation Index to monitor and assess the impact of dumpsites on the environment in Yenagoa Metropolis, Bayelsa State Nigeria. The outcome uncovers that the LST at the dumpsites was higher than the immediate environment, and the SAVI, NDVI, and G-SWIR values were lower than the immediate surrounding. The high estimations of LST at the dumpsites portray the impact of gases released as a result of decomposition activities, while low values of SAVI and NDVI show vegetation reaction to soil and groundwater pollution due to leachate invasion, lastly G-SWIR indicates discriminations of moisture content of soil and vegetation in leachate infiltration. The outcome shows correlation is significant with the NDVI and G-SWIR value at each of the dumpsites which indicate indirect relationship R2. NDVI versus G-SWIR = 0.6271, NDVI versus SAVI = 0.9084, these values indicate highly significant correlated in dumpsite reflectance, while SAVI versus G-SWIR = 0.73 is strongly correlated, indicating increase in waste quantity expected to result in high decomposition, gas emissions and contamination in the environment. The selected heavy metals analyzed for river water are lead (Pb), Zinc (Zn), iron (Fe), cadmium (Cd), nickel (Ni) and chromium (Cr6+). Indicated that all the heavy metals in river water are above the detectable limit by WHO 2011 which imply Epie creek is highly polluted and is due to illegal dumpsites present.