<p>The turquoise to sky-blue color appearance of freshwater bodies are nicely explained with examples in a 2016 paper by Kumar entitled &quot;<a href="https://www.researchgate.net/publication/311770515_STUDY_ON_TURQUOISE_AND_BRIGHT_SKY-BLUE_APPEARING_FRESHWATER_BODIES" rel="noreferrer"><strong>Study on turquoise and bright sky-blue appearing freshwater bodies</strong></a>&quot;.</p>
<p>In this paper, the author explains the cause of these shades of greenish-blue shades found in freshwater bodies around the world and proposes a classification/categorization of such freshwater bodies. the author has classified different turquoise to sky-blue appearing freshwater bodies into two major classes:</p>
<p>1)Natural</p>
<p>2)Anthropogenic</p>
<p>Such water bodies with causal factor of natural origin are placed under 'natural' and causal factor of non-natural (anthropogenic) origin are placed under 'anthropogenic' category. The 'natural' category has been further sub-classified into three sub-class : a. Glacial Fed (streams, lakes appears turquoise to sky-blue due to scattering of light by glacial flour (rock flour), ex- Phoksundo lake (Nepal), Moraine lake (canada), etc .
b. Volcanic and Hydrothermal: Lakes and rivers in volcanic region and of hydrothermal origin also appear turquoise to sky-blue. For example, kawah Ijen (Indonesia), Yudamari lake (Japan) which appears blue as a result of scattering from sulphate and ferrous particles. Rio celeste in another river in Costa Rica which appears turquoise as a result of scattering from aluminosilicate particles. c. Calcium carbonate rich: Calcium carbonate rich freshwater bodies also appear turquoise to sky-blue as a result of scattering from suspended calcite particles. Example,Havasu creek (grand canyon), Bear lake(Utah), Plitvice lakes (Croatia).</p>
<ol start="2">
<li><p>Anthropogenic : The author has discussed two water bodies appearing turquoise to sky-blue. Lukha river (Wah Lukha) which flows in meghalaya (India) turns turquoise every year in winter season, real cause not known but coal and limestone mining cited as a reason. Wilge river (S Africa) flows in coal mine affected area appears turquoise and aluminium has been cited as causing agent.</p>
<p>I would recommend reading the paper if you are interested in getting a deeper understanding. Picture 1. Different Glacial-fed freshwater bodies. 2. Calcium carbinate rich freshwater bodies. 3. River appearing turquoise as result of anthropogenic activities.
<a href="https://i.sstatic.net/NXWSW.png" rel="noreferrer"><img src="https://i.sstatic.net/NXWSW.png" alt="different glacial lakes" /></a>
<a href="https://i.sstatic.net/PYCSU.png" rel="noreferrer"><img src="https://i.sstatic.net/PYCSU.png" alt="Calcium carbonate rich " /></a>
<a href="https://i.sstatic.net/JaZfx.png" rel="noreferrer"><img src="https://i.sstatic.net/JaZfx.png" alt="anthropogenic" /></a></p>
</li>
</ol>

CC BY-SA 3.0
2017-07-13T20:04:46.020Z
Can you summarize the findings of the paper in your answer? Otherwise your answer is 'link-only' which is discouraged here.
kingledion
CC BY-SA 3.0
2017-07-12T05:39:05.697Z
2017-08-01T04:12:53.480Z
2020-06-18T08:25:19.090Z
Natura
<p>Dissolved micro particles of calcium carbonate, aluminum etc in the water coupled light reflection and resultant spectral wave cause various color in the lake water. It is unlike algie (red) found in Red Sea.
Light reflection and depth is a major factor because the same water look regular water in s test tube.</p>

CC BY-SA 3.0
2018-03-04T22:10:09.007Z
2018-03-04T22:10:09.007Z
user12374
<p>I recently visited Slovenia where I saw several rivers with a strong blue-green color.
Here is an example from one of the tributaries of the Soča river near Kobarid. The locals refer to it as an "emerald" color.</p>

<p><img src="https://i.sstatic.net/BvMLw.jpg" alt="Emerald blue-green river in Soča valley"></p>

<p>Notice how the color gets more intense at the deeper waters. What causes this color? A web search shows that the two most cited reasons are blue-green algae and "limestone particles". I'm guessing that the more plausible explanation in this case is the limestone one, because this area is dominated by limestone. But, is it really "particles"? I would think that the calcium carbonate would dissolve in the water, instead of being suspended as solids.</p>

CC BY-SA 3.0
2016-10-07T08:34:18.940Z
Other rivers in limestone areas show such colour. For example, Urederra in Navarre (in the Ebro basin): https://commons.wikimedia.org/wiki/File:Urederra.JPG
Pere
<rivers><limestone>
Why are alpine river water green - blue?
Gimelist
# Why are alpine river water green - blue?

(Asked by: username_0 on 2014-09-24)

I recently visited Slovenia where I saw several rivers with a strong blue-green color.
Here is an example from one of the tributaries of the Soča river near Kobarid. The locals refer to it as an "emerald" color.

![Emerald blue-green river in Soča valley](https://i.sstatic.net/BvMLw.jpg)

Notice how the color gets more intense at the deeper waters. What causes this color? A web search shows that the two most cited reasons are blue-green algae and "limestone particles". I'm guessing that the more plausible explanation in this case is the limestone one, because this area is dominated by limestone. But, is it really "particles"? I would think that the calcium carbonate would dissolve in the water, instead of being suspended as solids.

**Tags:** rivers, limestone

> **Comments:**
> **username_1**: Other rivers in limestone areas show such colour. For example, Urederra in Navarre (in the Ebro basin): https://commons.wikimedia.org/wiki/File:Urederra.JPG  

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## 2 answers

### Answer by username_2 on 2017-07-12. Score: 11

The turquoise to sky-blue color appearance of freshwater bodies are nicely explained with examples in a 2016 paper by Kumar entitled "[**Study on turquoise and bright sky-blue appearing freshwater bodies**](https://www.researchgate.net/publication/311770515_STUDY_ON_TURQUOISE_AND_BRIGHT_SKY-BLUE_APPEARING_FRESHWATER_BODIES)".

In this paper, the author explains the cause of these shades of greenish-blue shades found in freshwater bodies around the world and proposes a classification/categorization of such freshwater bodies. the author has classified different turquoise to sky-blue appearing freshwater bodies into two major classes:

1)Natural

2)Anthropogenic

Such water bodies with causal factor of natural origin are placed under 'natural' and causal factor of non-natural (anthropogenic) origin are placed under 'anthropogenic' category. The 'natural' category has been further sub-classified into three sub-class : a. Glacial Fed (streams, lakes appears turquoise to sky-blue due to scattering of light by glacial flour (rock flour), ex- Phoksundo lake (Nepal), Moraine lake (canada), etc .
b. Volcanic and Hydrothermal: Lakes and rivers in volcanic region and of hydrothermal origin also appear turquoise to sky-blue. For example, kawah Ijen (Indonesia), Yudamari lake (Japan) which appears blue as a result of scattering from sulphate and ferrous particles. Rio celeste in another river in Costa Rica which appears turquoise as a result of scattering from aluminosilicate particles. c. Calcium carbonate rich: Calcium carbonate rich freshwater bodies also appear turquoise to sky-blue as a result of scattering from suspended calcite particles. Example,Havasu creek (grand canyon), Bear lake(Utah), Plitvice lakes (Croatia).

2. Anthropogenic : The author has discussed two water bodies appearing turquoise to sky-blue. Lukha river (Wah Lukha) which flows in meghalaya (India) turns turquoise every year in winter season, real cause not known but coal and limestone mining cited as a reason. Wilge river (S Africa) flows in coal mine affected area appears turquoise and aluminium has been cited as causing agent.

   I would recommend reading the paper if you are interested in getting a deeper understanding. Picture 1. Different Glacial-fed freshwater bodies. 2. Calcium carbinate rich freshwater bodies. 3. River appearing turquoise as result of anthropogenic activities.
   [![different glacial lakes](https://i.sstatic.net/NXWSW.png)](https://i.sstatic.net/NXWSW.png)
   [![Calcium carbonate rich ](https://i.sstatic.net/PYCSU.png)](https://i.sstatic.net/PYCSU.png)
   [![anthropogenic](https://i.sstatic.net/JaZfx.png)](https://i.sstatic.net/JaZfx.png)

> **Comments:**
> **username_3**: Can you summarize the findings of the paper in your answer? Otherwise your answer is 'link-only' which is discouraged here.  

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### Answer by username_4 on 2018-03-04. Score: 0

Dissolved micro particles of calcium carbonate, aluminum etc in the water coupled light reflection and resultant spectral wave cause various color in the lake water. It is unlike algie (red) found in Red Sea.
Light reflection and depth is a major factor because the same water look regular water in s test tube.


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