Abstract:Based on the general principles included in the performance of an evapotranspiration cover,the plant interception,the soil evaporation,the evapotranspiration,runoff,and the net infiltration are calculated considering Penman¢s potential evapotranspiration. The calculated net infiltration is input into an unsaturated flow model as a boundary condition to simulate the moisture transport and evaluate the performance of an evapotranspiration(ET) cover. The analytical results show that evapotranspiration is crucial to the moisture transport. Water contents of soils in the upper portion are sensitive to the variation of rainfall and evapotranspiration,whereas water contents of soils in the bottom remain almost remain unchanged. The storage and release of infiltrated water happen mainly within the root depth. A 120 cm thick ET cover with a good stand of plants and a root depth of 50 cm can satisfy the design requirement. The ET cover has an advantage over conventional landfill covers in reducing rainfall percolation.