Lake Travis is known to be one of the most beautiful lakes in Texas. Just a drive along its shore or even better, boating, floating or swimming in it, is a real treat. It has a deep bluish-green or emerald green color depending upon the time of day and the depth and clarity of the water. But where does that incredible color come from?  Let’s take a look!

A few things affect the colors of water in a lake or ocean; the type of sediment below the surface, the amount and type of dissolved minerals in the water, the sun’s angle and organisms living in the water.


Let’s first look at sediment.  If you have a better idea of the various colors different types of sediments produce, you will be better equipped to understand why the color of water can change with depth and location. Lake Travis has limestone beds and is surrounded by limestone cliffs. This is the type of geography and resulting dissolved mineral sediment that produce colors that are blue-green or emerald green. Lakes that are located near mountains tend to be a different color than lakes that are located in flat areas. This is because mountain lakes have more dissolve minerals in them while lakes in flatter areas have less dissolve minerals. For instance, Yellowstone National Park has many lakes that are a green or yellowish in color. This is because this water contains a large amount of dissolved minerals that include both iron and sulfur.

Time of Year

The color of water can also vary depending on the time of year. This is because the sun’s angle changes throughout the seasons. Sunlight reflecting off and passing through the water at different angles affects how the water appears to the eye. With changes in season we also have changes in temperature and precipitation levels. So for example during the winter months, snow runoff can cause rivers and lakes to turn an icy-white color.


Depth will also contribute to a body of water’s color.  Deeper waters generally look darker than shallower waters. Ocean water can have many different colors depending on where you’re located. The ocean in the Caribbean tends to be lighter blue or turquoise blue, while the ocean near California is usually a darker, deep wine color. This is because the Caribbean is warmer, shallow and has more dissolved minerals in it. The Pacific Ocean near California is colder, deeper and has less dissolved minerals in it.


Finally ocean and lake color is affected by the presence of phytoplankton. These are the plant-based organisms of the plankton community that play a key role in ocean and freshwater ecosystems. The name phytoplankton comes from the two Greek words meaning plant and wanderer or drifter. Phytoplankton are photosynthesizing microscopic organisms and bacteria that live in the top sunlit layer of most oceans and fresh water bodies on the earth.  For example, some lakes get their color from algae blooms. These blooms can turn the water red, purple or brown.  Saltwater often has a greenish-blue color and this is partly from the presence of Phytoplankton.


So there you have it! The next time you’re on a body of water like beautiful Lake Travis you won’t take that splendid water color for granted. You’ll understand just why it’s so pleasing to your eyes and has moved your heart.