Two main natural processes were studied in the Yamin Plain in order to evaluate the thickness of a cover layer of a near-surface waste disposal facility, needed to prevent potential migration of radioactive contaminants to the biosphere. The first is the natural erosion rate of the cover layer, and the second is the infiltration depth during rain and runoff events. The erosion rate was studied by optical stimulation luminescence technique. It was found that during the last 14,000 years, the erosion rate was 0.3 mm/y. The infiltration depth assessment was based on water content measurements and numerical modeling. It shows that in the most extreme rain even having an equivalent rain of 84 mm, infiltration depth was limited to 4.5 m. Therefore, effective cover layer over 10,000 years, should be at least 7.5 m thick.