The important characteristic feature of environmental modelling is the complexity and uncertainty of its mathematical representation (uncertainty of formula). Imprecision of its input data is another characteristic feature, where it is not possible to omit influences of primary monitoring (e.g. gaps of data, errors of measuring facilities, human factor, etc). Many parameters in algorithms and their mathematical formulations are substituted by empirical constants in praxis, although it is well known that their values are very volatile and input data are not validated. Nowadays, information and communication technology (ICT) capabilities are growing rapidly and applied mathematical software (e.g. computer algebra systems, statistical packages, etc) becomes more powerful to overcome problems with formula complexity and uncertainty. The basic methods how to deal with the data uncertainties are well known and standardized from the last century, but some of their comparisons and recommendations for environmental modelling are not known enough. Paper presents generalized approach and shows universal methodology how to use current ICT tools for the implementation of mathematical models with formula and data uncertainties.