In the software of MONERIS 3.0 included is a pre-processing tool. It can be accessed through the second desktop icon. The pre-processing tool is used for a semi- automated preparation of the input data for MONERIS. ....Im Werkzeug enthalten sind Standarddatensätze wie sie in MONERIS Eingang finden. ..... With the help of the pre-processing tool most of the MONERIS input data can be prepared and directly imported to the Moneris-in.mdb. One part is a tool that supports the preparation of the flow net equation and the water bodies. The water bodies needs to be differentiated into main river and tributary. In addition the lakes in a main river at the outlet of an analytical unit can be differentiated into deep and shallow lakes or reservoirs. Dependent on the form and quality of the data this differentiation can be handled manually or automated. However, the manual preparation already leads to a time saving in comparison to the standard data preparation in GIS. Through the import the prepared data are directly written into the Moneris-in.mdb. Thereby the flow net defined via the pre-processing tool is transferred into a flow net equation, that is used to define the Id of every analytical unit. A detailed description on how the data are prepared or rather needs to be prepared with the pre-processing tool is installed with the software.