Mục quan tâm bao gồm thiết kế trong ước tính của thoát hơi nước (ET), dòng chảy bề mặt, và thấm sâu. Ngoài ra, việc đánh giá nên ước tính xác suất thành công, đòi hỏi phải ước tính hàng ngày Malthus về hiệu suất hơn nhiều năm hoặc nhiều thập kỷ. Các quá trình tương tác và hiệu suất phối bao gồm bãi rác, sự tương tác phức tạp giới thiệu vào các thách thức mô hình. | 9 Models for Design and Evaluation Items of interest in design include estimates of evapotranspiration ET surface runoff and deep percolation. In addition the evaluation should estimate probability for success thus requiring daily estimates of performance over many years or decades. Interacting processes govern ET landfill cover performance the interaction introduces complexity into the modeling challenge. A model that incorporates all of the important elements of engineering design including the interactions between weather plants and soil best serves engineering design and evaluation of ET covers. The model used for design or evaluation of an ET landfill cover should produce estimates that allow the user to evaluate the cumulative effect of each day s water balance activity and thus identify critical events. A MODEL PHILOSOPHY All numerical models calculate an approximation to a specific real-world topic of interest. When used for their intended purpose they are often useful. However it is inappropriate to use a model created for one purpose to estimate a solution to a problem not within the scope of the original purpose of the model. For example an economics model is not suitable for design of a landfill cover. In the same way it may not be appropriate to use a model developed for design of conventional-barrier landfill covers to estimate performance of an ET landfill cover. The engineer should select a design model that is appropriate for the problem. REQUIREMENTS FOR ET LANDFILL COVER MODELS The requirements for model estimates of ET cover performance are different from those for conventional landfill covers. Conventional cover design focuses on barrier-layer design and performance. The focus in an ET cover design is on water balance within the cover as controlled by weather plant growth soil properties and related ingredients. The ET landfill cover relies on using the soil as a water reservoir and grass or other plants to empty the reservoir rapidly .
