What I did leave out is heat ...
Published by Andrew Raal, Natural Scientific Professional
What I did leave out is heat pollution, infrared scanning can determine deference in temperature in a water body, e.g. a power station releasing hot water into a river, the extent and path of water can be tracked. I know of one proposal where they were going to try and identify groundwater inflow into a water body by looking at temperature difference, might be useful in hydrology!!