There is a stream/river with permanent white (milky) water color in Southern part of Blue Nile, Ethiopia. The Gumz tribes living around it call this river " Impua Aya" in their language. Impua mean "White" and Aya " Water" in English. The color of water doesn't change with time and space according to the people who told me. I appreciate any one who can tell me the probable causes for the permanent whiteness (milky) color of the water of this stream.
With kind regards.
Kassahun Birhanu
It is known that the Blue Nile carries most of the sediment and waters into the nile river (in comparissson to the White Nile). Since most of the headwaters of the Blue Nile are located in Ethiopia I would suspect the origin of this milky color lies in the geology of the area. A quick look on the geological map of Ethiopia shows that most of the upper nile watershed is dominated by igneous rocks, which should not be the cause for high dissolved or suspended solids. South of Mount Choqa where the Nile turns East there is an exposed sedimentary deposit covering a large extension of the Nile Gorge. This would be my first suspect for the origin of dissolved/suspended sediments giving "milky" color to the water of the Nile.
OK, now I have seen you are talking about another river. But maybe this helps you. What is the location of this tributary?
The pictures do not show the extent of the milky blue waters of Havasu Creek, tributary to the Colorado River at Grand Canyon. The springfed waters high in calcium carbonate is the explanation. If you have limestone substrate, that could be a possibility. Many of the Missouri springs in karst topography are not milky, per se, but have this bright blue to blue green tinge or coloration that is striking.
https://en.m.wikipedia.org/wiki/Havasu_Creek
The only other reason I could think of would be I have seen local deposits of white clays, or marl like clays and if this fine material were put in suspension from erosion, it would not settle.
I forgot to mention, glacial melt may also have a milky character.
I became interested and looked it up, its called glacial milk or rock flour.
https://en.m.wikipedia.org/wiki/Rock_flour
Dear Rafael Anleu and William F. Hansen
I would like to thank all of you for your valuable responses to my question. I don't know the exact location of this stream but it is around 0231387.94m E and 1164189.67m N. About 20-30 kms South of Borabo.
May be the waters are coloured by effluent from any dairy plant located nearby. I saw such event several times in Belarus
Dear Mr. Golubev,
Thank you for your response. The river is found in remote area far from any type of human settlement or industry. It cannot be polluted by artificial means. Its colour is naturally existing.
Part of my life I spent in West Africa in the region of the upper tracts of the Volta River. Definitely in Northern Ghana and Burkina Faso (earlier named Upper Volta) there are three rivers distincted by their colour prior to their confluence into the main Volta. There are the Black- the White- and the Red Volta rivers.
The colour of the water is due to the sediments carried. Black Volta is the cleanest river, the name refers ro the clean water itself, since it is not tinted. The two latters are carrying microscopic sediments. Especially the red is very characteristic, since both the silt and clay fractions of the soil of that region contain Fe oxides.
I thank you professor.
There are also two white streams in this area in Ethiopia. One of them is permanently flows through out a year. Where as the second dries during dry season. We can get very cold white water under the sand when we scrab or dig a sand from a stream bed with our hand.
I would look at the mineralogy of sediment sources in the catchment upstream from this site. We have seen milky white water in some rivers in UK which is particularly marked when the sun is shining on the surface of the water. What was rather confusing was that when we filtered the water samples, the sediment mass was relatively low. We undertook a mineralogical analysis on the trapped sediment on the filter papers and discovered a high proportion of the sediment load was in the form of illite. This is a clay mineral with a lattice alumino-silicate structure taking the form of a platelet. When the sun shone on the particles in suspension, the reflection from the platelet structure gave the impression of a milky white water column. In our river this was caused by the drainage of clay soils for agricultural production, leading to an increase in the rate of delivery of these particles. It would be entirely possible, however, for this to be a natural phenomenon if there was a high proportion of such sources in your catchment.
Note, as these minerals have a platelet-type structure, they require less energy to stay in suspension (considering their area to mass ratio) than a spherical particle, and in our examples would stay in suspension for many weeks after a high flow event delivering fresh sources to the water column.
Dear Penny J. Johnes,
I thank you so much for your interesting explanations for my question.
Kind regards
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