Excerpt from The Hydraulic Principles Governing River and Harbor Construction During his professional career the writer has prepared numerous projects, and has answered many criticisms of the methods employed in the improvement of rivers and harbors. The following pages are derived principally from these sources. In replying to complainants, the author came to the conclusion that there was a commendable interest among the American people in the subject of the improvement of rivers and harbors, and a deplorable ignorance of the fundamental principles governing the flow of water in natural channels. Such is his apology for this publication. The ordinary textbook on hydraulics treats principally of the flow of water in pipes and conduits, and the ordinary engineer is apt to consider a river as merely a large conduit governed by the same laws, ignoring the change in conditions arising from the fact that the walls of a pipe are not affected by the velocity of flow through it, while the channels of a silt-bearing stream expand or contract with every change in the volume of discharge. This fact is ignored also by many writers on river hydraulics, whose textbooks contain more or less elaborate discussions of the formulas which are authoritatively stated as guides for determining the depth in a contracted waterway. In a rock cut, these formulas give as accurate results as they do when applied to a sewer or to a pipe, but in the alluvium of the Mississippi or Missouri rivers, scour caused by the contraction produces a radical change in the hydraulic radius. Water flowing in a river channel is governed by the same immutable laws as when flowing in pipes, but theses laws are so modified in the river by those governing the flow of sediment that effects are produced which are erroneously termed exceptions to general laws. For example if a given pipe is replaced by one of less diameter, the head (slope) must be increased to obtain the same discharge. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.