Kriel is a town in Nkangala District Municipality in the Mpumalanga province of South Africa. The Kriel Power Station is located just outsiā¦Kriel is a town in Nkangala District Municipality in the Mpumalanga province of South Africa. The Kriel Power Station is located just outside the town. With barter agreement between Carel Trichardt and King Sabusa of Swaziland, Carl Trichardt became owner of Eastern Highveld. In 1896, Paul Kruger donated the farm Onverwacht to two brothers, Willem and Pieter Grobler. During the same year two brothers Fasie and Fleetwood de Kock also played a big role in the history of this district. After the Peace Agreement in 1902, Fasie de Kock asked the Milner Government to open the first school in Kriel. Laerskool Onverwacht was opened on 31 July 1903 in a small Milner building with Mr R. McCloud as the Scottish headmaster.