Field monitoring and model predicted water balance of monolithic cover

Abstract

The use of the evapotranspiration cover for landfill is increasing because of its long-term enhanced performance. However, the performance of evapotranspiration cover primarily depends on the onsite geo-climatic conditions. Therefore, field verification of cover performance through constructed test plots is required before actual implementation. Additionally, numerical modeling and comparison with field results are necessary for future performance prediction. The objective of this study was to simulate the water balance hydrology of evapotranspiration cover using the code SEEP/W. Drainage lysimeter was constructed with fine-grained soil and native vegetation. Field water balance data from the lysimeter were obtained through instrumentation. Onsite climatological data, laboratory and field investigated soil parameters and actual field studied plant parameters were used as model input. Based on one year’s simulation, it was observed that the code nearly captured the seasonal variations in the water balance quantities measured in the field. Surface runoff was reasonably predicted in the model where precipitation intensity appeared to be responsible to some extent. Evapotranspiration was slightly overpredicted and the fluctuation in soil water storage was similar to the field results. The model predicted annual percolation was approximately 45 mm, which is under-predicted than the actual field measured annual percolation of 62 mm.