Methods for generating alternative solutions to water resources planning problems

An optimization model is generally not a perfect representation of a complex water resources planning problem because not all important issues can be captured in a model. Optimization models can be used in a planning process to generate planning alternatives that are good and different so that the analyst and the decision maker can examine a wide range of alternatives t.0 gain insight and understanding. This approach is called modeling to generate alternatives (MGA). Several new MGA methods, a random method, a branch and bound/screening (BBS) method and a Fuzzy BSJ method, are described. This work also provides an assessment of the potential use of these methods as well as the HSJ method for generating good and different alternative solutions; the methods are illustrated using a wastewater treatment system planning problem, which is formulated as a mixed integer programming (MIP) model.U.S. Geological SurveyU.S. Department of the InteriorOpe