Ok, I got interested and did some reaserch:
- The lake 'Barubashi' is Lake Balkhash (the only googlable toponym)
- It appears there's no creature named 'sarud', 'sarut' or something like that in Kazakh mythology (and 'salud' means 'to build').
- The closest thing probably is 'Cу ээзи' or 'Cуг ээзи' (Su Eezi/Sug Eezi, pron. Soo[g] eh-eh-zee, 'eh' as 'e' in 'pet'), Kazakh 'Су иесі', literally "master of water" - a spirit of water in Altai shamanism, and some sources mention it as part of ancient Kazakh pagan beliefs as well.
Video of ritual of offering to Su Eezi:

However, as an elemental spirit of nature it shouldn't be as aggressive and short-tempered as said in the article.

- Also there's 'ubbe', Kazakh evil spirit of water, but sources say it's almost disappeared from folklore since the adoption of Islam.