Earthwork Slips and Drainage.

Mr. John Newman, in his admirable treatise on “Earthwork Slips and Subsidences upon Public Works,” classifies and enumerates slips as follows:

After describing each cause he presents 39 different means used to prevent such slips and describes methods of making repairs.

Mr. Wm. L. Strange has had such a large and valuable experience and has set forth so carefully and lucidly both the principles and practice of earth dam construction, that the writer takes pleasure in again quoting him on the subject of drainage, of which he is an ardent advocate. He says that,

thorough drainage of the base of a dam is a matter of vital necessity, for notwithstanding all precautions, some water will certainly pass through the puddle.

It is at the junction of the dam with the ground that the maximum amount of leakage may be expected. The percolating water should be gotten out as quickly as possible. The whole method of dealing with slips may be summed up in one word–drainage.

The proper presentation of these two phases of our subject would in itself require a volume. The interested reader is therefore referred to the different authorities and writers cited in [Appendix II].