FIFTEENTH ANNUAL REPORT

OF THE

RECLAMATION SERVICE.

GENERAL DISCUSSION.

DEVELOPMENT OF RECLAMATION PROJECTS.

During the past year the operation of the reclamation laws has continued to advance their objects as shown by the increase in the area for which the service could supply water, the increase in the areas actually irrigated and cropped, the increase in the value of crops produced, and the increase in the actual number of settlers and of homes. The progressive increase in these elements is shown in the following table:

PRINCIPAL CONSTRUCTION RESULTS DURING YEAR.

No new projects have actually been taken up within the fiscal year and none will be without express authority from Congress.

The Salt River project has been completed and is ready for issue of public notice. Some damage was caused by floods in January, 1916, which has mostly been repaired. The power development incident to this project has resulted in the delivery of large quantities of power for mining and other industrial and domestic uses, yielding large monthly revenues.

On the Yuma project, the distribution system of the Yuma Valley has been extended to additional lands and this is practically completed. Water is now available for all the irrigable lands in the valley south of Yuma. Progress has been made in the revetment of levees with rock to protect this valley from the incursions of the river. Nearly half of the irrigable land on the California side,

5

amounting to about 3,000 acres, is injured by seepage, and requires drainage, which has not been authorized by the entrymen.

The construction of the Orland project has been practically completed with the exception of some provision for the care of storm water and waste water. The project has been opened by public notice and construction payments will begin October 1, 1916.

The construction of the Grand Valley project is under way. The completed portion of the main canal is being tested and primed and some water can be delivered during 1917 on a rental basis. The main canal in places passes through deep cuts in shale which have developed crevices allowing seepage from the canal to the injury of lands below. This is being corrected by puddling such places with clay and other suitable material obtainable in the vicinity.

The Uncompahgre Valley project is approaching completion, the work during the past year comprising the operation of completed works under the laterals constructed and the enlargement and extension of the Ironstone Canal and construction of laterals therefrom to cover new land.

On the Boise project, the Arrowrock Dam has been completed, furnishing storage on the Boise River to the amount of 250,000 acrefeet and regulating the flow at all times for diversion by the main canal below either for irrigation direct or for storage in the Deer Flat Reservoir. The water supply as thus regulated is capable of supplying from 20,000 to 30,000 acres of land not yet reached by canals. Surveys are in progress to determine where this can best be used, as there are possibilities on both the north side and the south side of the river. The land under canals, amounting to 230,000 acres, is being served on a rental basis and is ready for opening under public notice at an early date.

On the Minidoka project, the gravity portion has been under public notice for some years and public notice has been issued recently for the pumping portion. The gravity portion recently voted by a large majority to take over the operation and maintenance of the system, and contract to this effect has been entered into under the provisions of the reclamation extension act.

The enlargement of Jackson Lake Reservoir under contract with the Kuhn Irrigation & Canal Co. and the Twin Falls Canal Co., by which these companies will be provided with about 400,000 acre-feet of storage capacity, is nearly completed. The funds for this work were advanced by the above-named companies.

On the Huntley project drainage work is under way and has been successful in relieving the waterlogged lands in the vicinity of the drains.

Construction on the Milk River project has been prosecuted actively during the year. The feed canal from St. Mary River to the Milk River has been completed and is being seasoned ready for use in 1917. Work is under way on the Sherburne Lakes storage dam, and the diversion of Swift Current Creek into St. Mary Lake has been accomplished. The Vandalia Diversion Dam has been completed with the exception of the movable crest, and water is being delivered therefrom. The development of Nelson Reservoir has been completed and water is being carried into that reservoir by the Dodson South Canal.