Complex sentence: Long Grass Plantation is located along what was the Roanoke River basin but in the 1950s became the Buggs Island Lake/John H. Kerr Reservoir in Mecklenburg County, Virginia.
Split into simpler sentences: Long Grass Plantation is located along what was the Roanoke River basin. In the 1950s it was flooded as the Buggs Island Lake/John H. Kerr Reservoir in Mecklenburg County, Virginia.