More info about Yevgeny Prigozhin and Wagner group:
http://www.bbc.com/news/world-europe-43167697
2 min video https://vimeo.com/ondemand/138903
He writes that the objective was not the Conoco oil installation, but the US SF that were embedded there. If they had succeeded with it it would be a blow to the US prestige in the region and would result in the withdrawal of US forces like in Lebanon 1984 and Somalia 1994.
Russian Army build a bridge. but on February 6, the water level in the Euphrates suddenly rose by several meters, and the speed of the current increased two-fold.
The next day the bridge was demolished, and the Wagner Group was cut off, but still started the operation.
The Russian military believes that the discharge of water originated from the reservoir of El Tabbah HPP upstream, that is controlled by the SDF units.
The Russians started the attack in the evening when it was dark believing that US forced would be unable to discriminate between friends and foes and refrain from counter attacking. In other words they assume that the situation was similar to the eastern parts of Ukraine.
All communications to and from the Wagner groups were suppressed by http://www.af.mil/About-Us/Fact-Sheets/Display/Article/104486/ac-130u/ and the result could only be one.
Colonel-General Alexander Zhuravlev will have a tough time explaining what happened and the battle has diminished the morale of the Russian forces with big consequences.
https://www.novayagazeta.ru/articles/2018/02/20/75571-razgrom