Characteristics of Problems to be Modeled

Problems motivating modeling and analyses exhibit a number of common characteristics. These are reviewed here because they provide insight into whether a modeling study of a particular problem may be worthwhile. If the planners’ objectives are very unclear, if few alternative courses of action exist, or if there is little scientific understanding of the issues involved, then mathematical modeling and other more sophisticated methodologies are likely to be of little use.

Successful applications of modeling are often characterized by:

·         A systems focus or orientation. In such situations attention needs to be devoted to the interdependencies and interactions of elements or components within the system as a whole, as well as to the elements or components themselves.

·         The use of interdisciplinary teams. In many complex and nontraditional problems, it is not at all clear from the start what mix of disciplinary viewpoints will turn out to be most appropriate or acceptable. It is essential that participants in such work—coming from different established disciplines—become familiar with the techniques, vocabulary, and concepts of the other disciplines involved. Participation in interdisciplinary modeling often requires a willingness to make mistakes at the fringes of one’s technical competence and to accept less than the latest advances in one’s own discipline.

·         The use of formal mathematics. Most analysts prefer to use mathematical models to assist in system description and the identification and evaluation of efficient tradeoffs among conflicting objectives, and to provide an unambiguous record of the assumptions and data used in the analysis.

Not all water resources planning and management problems are suitable candidates for study using modeling methods. Modeling is most likely to be appropriate when:

·         The planning and management objectives are reasonably well defined, and organizations and individuals can be identified who can benefit from obtaining and understanding the model results.

·         There are many alternative decisions that may satisfy the stated objectives, and the best decision is not obvious.

·         The water resources system and the objectives being analyzed are describable by reasonably tractable mathematical representations.

·         The information needed, such as the hydrological, economic, environmental, and ecological impacts resulting from any decision, can be better estimated through the use of models.

·         The values of the model parameters are estimable from readily obtainable data.