Sedimentary soil shall be cleared when reaching 50% of the capacity. Sedimentation tank shall be cleaned or sand therein shall be replaced in case of drainage difficulty.
当沉积土达容量的50％时，清理沉积泥土；当沉淀池排水不畅时，清理或替换砂砾；
2
Using alternant dem the study raised a new method based on the relation of sedimentation and precipitation to acquire the amount of soil erosion on hillslopes.
Soda salinity was mainly enriched in the sedimentation area of Holocene basin centrally of which was the serious disaster area of modern soil salinization.