The Yinshan mountain range which forms the northern boundary of the Yellow River basin borders the Hetou irrigation region in Inner Mongolia and shelters it from the fierce northwester which brings sand and dust to the entire North China plain. From the looks of it, these mountain peaks may contribute a substantial amount of the transported sand and dust.

Picture source: YRCC, Huanghe Liuyu Ditu Ji, China Atlas Pub House, 1989.