The finite element method (FEM) is one of those modern numerical methods whose rise and development was incited by the rapid development of computers. This method has found applications in all the technical disciplines as well as in the natural sciences. One of the most effective applications of the finite element method is its use for the solution of groundwater flow problems encountered in the design and maintenance of hydraulic structures and tailing dams, in soil mechanics, hydrology, hydrogeology and engineering geology. The stimuli to write this book came from the results obtained in the solution of practical problems connected both with the construction and maintenance of fill-type dams and tailing dams and the utilization of groundwater in Czechoslovakia, and on the other hand from the experience gained in teaching hydraulic structures theory at the Faculty of Civil Engineering of the Technical University of Prague. All the experience so far obtained shows markedly the advantages of the finite element method and the great possibilities of its further development as well as its considerable demands on the algorithmization, programming and use of computer possibilities.