Page:Report of the Oregon Conservation Commission to the Governor (1908 - 1914).djvu/271

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Records of river disharge have now hen obtained by the United States Geological Survey, in cooperation with the State, for a long enough time to enable a fairly intelligent estimate of the probable future irrigation development of the State to be made. Such an estimate is presented in the following tables and discussion. It must be borne in mind that the statements of the probable use of water, are in many instances, for the rather distant future, and perhaps not over half of the possible irrigation developments will come within the next 20 years.

Detail surveys of the irrigable valleys of the state have been made in but a few instances and it is therefore impossible more than to approximate the irrigable area. A considerable number of reservoirs have been surveyed, and others have been examined carefully enough to show whether or not they are feasible. In many cases the reservoir site could be developed to a much larger capacity than the average runoff of the drainage area.

IRRIGATION FROM POWDER RIVER

A brief summary will be presented of the storage and irrigation possibilities of the most important streams of the State. It shows that there is available from the streams of Oregon a water supply sufficient to irrigate over 4,000,000 acres of land.

An estimate of the total runoff of streams and of the portion susceptible of diversion for irrigation; substantially an inventory of water available for irrigation, together with certain facts in regard to the records are presented in the following table: