UwEM, (Underwater Environment Monitoring), is a sonar decision support system within Hydra, the new multisonar system on board the Visby Class Corvette. Many functions, databases and models for prediction of sonar performance are identical to those in the stand alone system HAIS-III, (Hydroacoustic Information System version 3). The systems provide the possibility to store extensive and complex sediment databases in formats which in general are not available. Without relevant bottom data the systems will not work. In this report we show how existing data can be changed and complemented to fit the format and in this way create a first preliminary database. The proposed modifications concern parameters valid for low frequency surveillance. These parameters are required by models performing propagation loss predictions in coming tests and verifications with UwEm /HAIS-III. Continued update of the database will be necessary to encounter the higher demands raised by operative systems. In recent years techniques using inversion have been tested to find the acoustic properties of the sediments. In this study we show an example where we have inverted data from a field experiment. The example shows that for very low frequencies shear properties also have to be included in the database.