Sensitivity of the Groundwater Mound Model for Predicting Mire Topography

The Dupuit-Forcheimer model for groundwater mounds has been proposed to explain the morphology of raised peat mires. This paper discusses the sensitivity of the model as a predictor for mire profiles using data from a raised Irish mire where an attempt was made to reconstruct the equilibrium profile. The most sensitive parameters are shown to be hydraulic counductivity and net recharge. Detailed measurements of saturated hydraulic conductivity show significant spatial variability, which is correlated with mire stratigraphy. Objective determination of an average value for modelling would have an error band of an order of magnitude which is unsatisfactory for prediction. Net recharge is calculated from the water balance but parameters like overlandflow must be estimated, usually from limited data, making the proposed value suspect. This model may be helpful for mire description but its variables cannot be specified accurately enough for predictive purposes.