The earth dam is probably the oldest type of dam in existence, The litera- antedating the Christian Era many hundreds of years. ture upon this subject is voluminous, but much of it is inaccessible and far from satisfactory. No attempt will here be made to collate this literature or to give a history of the construction of earth dams, however interesting such an account might be. The object will rather be to present such a study as will make clear the application of the principles underlying the proper design and erection of this class of structures. In no way, therefore, will it assume the character or dignity of a technical treatise. Dams forming storage reservoirs, which are intended to impound large volumes of water, must necessarily be built of considerable height, except in a very few instances where favorable sites may exist. Recent discussions would indicate that a new interest has been awakened in the construction of high earth dams. As related to the general subject of it storage, is with the high structure rather than the low that this study has to do. To the extent that the greater includes the less, the principles here presented are ap- plicable to works of minor importance. Many persons who should know better place little importance upon the skill required for the construction of earthwork embankments, considering the work to involve no scientific problems.