Assessment of Leachate Production from a Municipal Solid-Waste Landfill through Water-Balance Modeling
Mineral temporary capping systems of landﬁlls are required to accomplish the long-term coverage prerequisites or to use them as a basis layer prior to later permanent sealing. Such a capping system for a municipal waste landﬁll in Rastorf (Northern Germany) was developed and tested for its sealing capability on the basis of observed and simulated water balance components for the period between 2008 and 2015, considering observed local weather data and complemented by the Hydraulic Evaluation of Landﬁll Performance (HELP 3.95 D) model. The modeling results of this case study could be improved by the correction of previously used global solar radiation data due to the consideration of exposure and inclination angle of landﬁll surface areas. The model could positively be validated by comparing observed and simulated outﬂow (surface runoff and lateral drainage) data with R 2 values ranging between 0.95 and 0.99, as well as for the leachate rates with R 2 values of 0.78–0.87. The statistical-empirical HELP model was found useful in predicting the leachate generation of a temporary landﬁll capping system for speciﬁc soil and site conditions, even if only a restricted set of observed data was available.