STABILIZING STEEP SLOPES WITH GEOMEMBRANES

The effects of five types of geomembranes, placed at the soil surface, on runoff and erosion on steep earth slopes were studied under labora tory and field conditions. In the laboratory, the soil samples were pa cked in boxes held at a 50% slope and subjected to three consecutive s imulated rainstorms of 120 mm each. The membranes dissipated the drops ' impact and reduced runoff significantly compared with the control. T here was no significant difference among the membranes regarding their effect on the runoff. In the field, the membranes lined earth dikes o f 33-60% slope and 12-20 m length, during 2 years. There was no runoff and erosion from the lined plots compared with 80-125 tonne ha(-1) of erosion in the control plots. No considerable wear and tear of the me mbranes was observed. (C) 1997 Elsevier Science B.V.