 South Carolina's peak cotton crop was harvested in 1921 and thereafter, cotton production began a long and steady decline, due in part to boll weevil infestations and soil erosion.The New Deal programs of the 1930s prodded farmers into switching to crops, and cotton gradually became less and less important to the county's economy.In 1904 the Catawba Dam and Power Plant was completed and Lake Wylie was created.