Complex sentence: As of 2015, poverty remains a problem for the displaced populations in the Dakotas, who are still seeking compensation for the towns submerged under Lake Oahe, and the loss of their traditional ways of life.
Split into simpler sentences: As of 2015, poverty remains a problem for the displaced populations in the Dakotas. They have sought compensation for their towns submerged under Lake Oahe, and the loss of their traditional ways of life.