Why is water blue
There any many reasons why we see water as a certain color. But at it’s core, the color of water is blue. Water absorbs the red end of the spectrum. When light passes through water, depending on factors like depth and things discussed below, we see the sort of complying/reflecting color of red, which happens to be blue!
Oceans and lakes are blue in large part to the reflection of the Sky. Light has a large impact on the color of the ocean, so the clearer the day, the bluer the water. It’s also why it will appear more gray when there is a storm overhead. Remember, the main reason for this is because of light, if heavy clouds are present, less light will get through. The depth of water also plays an important factor. As it gets deeper, it will develop a stronger blue.
Water in swimming pools will reflect the color the inner walls. For example the more common white walls you see in community pools, will make the water appear with a turquoise hue. If the pool is deeper, it will show more blue.
Rivers and streams/creeks will vary and include more green, sometimes brown. This is in large part due to the fact that they are usually not that deep, and are moving. Because they move, it stirs and picks up a larger amount of different types of particles, rocks, that can absorb/reflect light. This also translates to why Caribbean water sometimes appear with more turquoise. The white sand in combination with very clean and particle free water will give off more of a turquoise hue. Other factors that play a role are algae, the reefs and plant life.
Water is amazing.