A useful starting point
Choose a viewpoint that does not require entering the water or moving onto an unstable surface. Make a short description, then compare it after a safe interval. Reflections and shadows may change the appearance of water and shore features. The exercise is about visible differences, not a conclusion about depth or conditions beneath the surface.
Try this sequence
- Keep the viewpoint fixed and lawful
- Note the time of each description
- Compare reflections and visible shadows
- Do not infer depth from colour
A small worked example
A reflection may disappear between two observations even though the visible shoreline seems unchanged. Record the different light and times without inventing an underwater explanation. The point is to understand how a view changes, not to treat a colour change as a measurement.
What to keep in your notes
When you review this exercise, keep the observation and the action on separate lines. Note whether the method was practical with your actual equipment and circumstances. If the answer is unclear, leave that uncertainty visible and seek the appropriate source before the next outing.