Show huge earth dam the big belle bourche clie irrigation dam in south dakota which Is the largest earth embankment in th the e world Is nearing completion con st ruction of the project was authorized by congress on may 10 1904 at a cost of from an engineering standpoint the delle belle bourche project Is one of the most interesting which the govern ment has yet undertaken its pal structure Is the earthen dam this wonderful dike which closes the lowest loest depressions in the rim of a natural basin Is feet long 20 feet wide nide on top and feet high in the highest place the inside face of this structure which has a slope of two to one will be protected from wave and ice action by two feet of screened gravel on which will be placed concrete blocks each four by six feet and eight inches thick the cubical contents of this dike will be cubic feet or about halt half of the famous pyramid of theopi the reservoir created by this dam will cover about acres and will be the largest lake in the state popular mechanics |