The first part of the book demonstrates an important risk management strategy - an original inseparable method for evaluation of the climatic and anthropogenic impacts on the average annual volume of water and on the maximum and minimum water flow of the Mesta and Struma River on the Bulgarian territory. The second part of the book uses a new method of multicriteria solution analysis, bearing the specific name Intercriteria Decision Analysis (ICDA). The method allows comparison of criteria / objects and on this basis to eliminate some of them. The method is used for the analysis and evaluation of the pollution indicators of the Struma and Mesta rivers.