Low-Head Hydroelectric Developments

In the last few years very rapid progress has been made abroad in developing the theory of low-head developments and this has resulted in a wider use of Kaplan turbines. Every engineer interested in the design of low-head developments should familiarize himself with at least the principles of this theoretical work and its practical application. The paper gives a general outline of the present situation which seems to have been somewhat neglected in the United States. Starting with general ideas about Francis, propeller, and Kaplan tarbines in low-head developments, the important points are discussed with respect to cavitation and pitting, modern design theories, design of propeller and Kaplan turbines and the research requirements and practise. Next the practical application of the theories are demonstrated by a table of designs executed or projected, and finally, some of the tendencies in extending the use of Kaplan turbines for higher and much lower heads are discussed.