Ground above the man-made slopes, roads, logging tracks and highways should be dug approx. 1m wide and 2-4m deep along the contour lines some 5 to 20 metres above the man-made slope.
Impervious foil should be placed at the bottom of the dug holes so that the water from the dug earth in the holes does not get into the pores underneath. It will then soak into this dug earth and, gradually, into the pores in lower layers of soil.