Monitoring and Evaluation of Evapotranspiration of Water Balance Cover: Fid-Bau Portal

Monitoring and Evaluation of Evapotranspiration of Water Balance Cover

Alam, Md. Jobair Bin / Rahman, Naima / Seraj, Farnaz / Hossain, Md. Sahadat

Water balance cover or evapotranspiration (ET) cover is an emerging landfill cover system for waste containment. ET cover follows the water store-release principles, and it works with the natural processes to create a better performing landfill cover compared to the performance of a conventional cover. In this type of cover system, evapotranspiration (ET) is the basic mode of water release from the cover to the environment. Hence, ET is the most significant water balance component for optimal cover performance. Among the various water balance components, direct measurement of ET has probably been the most difficult. In this study, ET was measured through the water balance method from six constructed drainage lysimeters having dimensions of 12 × 12 × 1.2 m. The lysimeters were constructed with local fine-grained soil and different native vegetation. All the lysimeters were equipped with instrumentation to have direct measurement of the water balance components except ET. Prediction of ET was also made based on models relying on meteorological information (e.g., temperature, solar radiation, relative humidity). The FAO-56 Penman-Monteith model and modified Thornthwaite model were used in predicting the potential evapotranspiration (PET). Based on the comparison of field measured actual ET through water balance measurement and model prediction, approximately 330–570 mm/year of ET deficit was observed. Different vegetation with varying root zone depth was found to have significant influence on the ET rate for the lysimeters.