08-12-2018, 07:56 AM
Water is colorless.
Before modern times, when images of blue water on tropical beaches became ubiquitous, people simply didn't think of water as necessarily blue. That is why in many medieval depictions, water can be both green and blue. That doesn't mean there's something in the water. It's just the way they conceptualized it.
Depending on the time of day, depth and so on, perfectly normal European rivers can appear blue, green, brown, grey and everything in between. No need for swamps and herbs.
Before modern times, when images of blue water on tropical beaches became ubiquitous, people simply didn't think of water as necessarily blue. That is why in many medieval depictions, water can be both green and blue. That doesn't mean there's something in the water. It's just the way they conceptualized it.
Depending on the time of day, depth and so on, perfectly normal European rivers can appear blue, green, brown, grey and everything in between. No need for swamps and herbs.