Algorithm Meerpeilcorrection is developed for the FEWS-meren project and was only tested in combination with a BlackBox wrapper configuration for SIMONA. The purpose of the algorithm within FEWS-meren is to correct the waterlevel at the start of a SIMONA-run in such a way that the total watervolume stays in accordance with measurements. The algorithm adds a uniform correction value to all values of the state, before starting the computation of the stochastic model. The correction value is provided by the stochastic observer (only one observation is expected).