Complex sentence: Below Scio, the creek receives Peters Ditch from the left and Sucker Slough from the right before entering the South Santiam River about above its confluence with the North Santiam River, with which it forms the Santiam River, a tributary of the Willamette River.
Split into simpler sentences: Below Scio, the creek receives Peters Ditch from the left and Sucker Slough from the right before entering the South Santiam River about above its confluence with the North Santiam River. The South Santiam and North Santiam merge to form the Santiam River, a tributary of the Willamette River.