Lanterna Rally

Author: John Dubuis

Publisher:

Published: 2015-07-22

Total Pages: 68

ISBN-13: 9781331966852

Excerpt from Report to Desert Land Board on Central Oregon Project: With Special Reference to Seepage Losses and Canal Capacities The following report contains data relative to the physical condition of the Central Oregon Irrigation Company's Project, together with certain conclusions therefrom. These conclusions in brief synopsis are herewith presented. 1. The total water lost in transmission through the canals from point of diversion at the river to place of use on the farmers' land, including losses in farmers' ditches, ranges from 67% to 75% of the total amount diverted from the river. 2. The losses in main canals and laterals from river diversion to point of delivery by the Company at or within one-half mile of the farmers' land, range from 45% to 57% of that diverted. Losses in main canals alone amount to from 25% to 40% of the water diverted from the river. 3. These heavy losses seem to be due to the porous, seamy nature of the lava rock which underlies the greater part of the segregation, to the relatively shallow soil, and to the character of construction of the canals. Caves, underground channels, and sink holes have been noted in places where this rock is exposed. Canals have been built wider and more shallow than proper, in order to avoid rock excavation. Where natural depressions were used the water has been allowed to spread over large areas. Since the loss of water is to a certain degree directly proportional to the wetted area, some of the excess loss is the natural result of this excess area. 4. The soil itself is relatively tight. Recorded losses sometimes run as low as 0.3 cubic foot per square foot of wetted area per 24 hours. Where the seamy rock is encountered however, the losses will run up to 3.0 cubic feet per 24 hours, and in the case of the North Canal the remarkable figure of 45.0 cubic feet per square foot of wetted area was obtained. 5. It is believed that in canals dug entirely in earth without encountering rock or gravel, the loss will be about 0.6 cubic foot per square foot of wetted area in 24 hours. 6. Evaporation loss in comparison with seepage and leakage loss is so small as to be negligible. 7. The greatest losses are in the main canals and the places of their occurrence are thus easily accessible. From this and other data at hand it is probable that losses in canals and laterals can be reduced to 40% of the total water diverted from the river without resorting to expensive methods of lining. 8. The duty of water of 1.8 acre feet per acre in 90 days may be sufficient after the project is well settled and all lands are under cultivation, although the settlers have been using more than this amount. (The proper duty for this or any project is not that which gives the greatest crop yield per unit of water used, but must take into consideration the cost of the land and water, value of crops, cost of labor, and other investment costs, and should be that which shows the greatest net profit in money to the farmer. A proper distinction should be made between the "economic use of water" and the "economic duty of water," as they are not synonymous terms.) 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.