„Waters of Bulgaria“ is a teaching unit aiming at helping teachers, but it could be used by students for self-preparation. It covers the required teaching material of Geography and Economics for 10th grade. The use of multimedia in education improves visual teaching, develops logical thinking and helps students to grasp new concepts in a more intelligible and easy way. This unit has been supplemented by some practical assignments targeting basic points in the teaching content. They have a clear focus and have been well shaped in technical and aesthetic terms. Using those assignments students get the opportunity to analyze the water resources of Bulgaria on their own and broaden their perspective on a large scope of ecological problems.