Mann Creek Reservoir

First settlers in the area were attracted in the early 1860`s by rich bottom lands. Most of them engaged in stock raising. The creation of Olds Ferry across the Snake River and the location of three forts in the vicinity of Weiser stimulated early development. Completion of the Union Pacific Railroad through Weiser and a branch line north to New Meadows in the 1890s gave further impetus to agricultural settlement of the area.

Early development of the project lands for irrigation was by direct diversions from Monroe and Mann Creeks. Ditches were constructed to meet the individual needs of the early farms.

The Mann Creek decree of July 17, 1919, established the water rights for the various ditches diverting from Mann Creek and the water rights for Barton Reservoir.

Investigations

The Bureau of Reclamation began the investigation of Mann Creek at the Spangler Reservoir site in 1938. A storage application was made in 1940 by the United States for 10,000 acre-feet of water. Results of the investigation were presented in a report on the Mann Creek Project dated October 1940. The project was approved for construction in July 1941 under the terms of the Water Conservation and Utilization Act. The land-owners of the Mann Creek area failed to approve the proposed repayment contract by a narrow margin, and the project was not constructed. One of the principal reasons given for rejection of the proposed plan was that the landowners below the Joslyn Ditch would not receive storage water at low reservoir stages.

An alternative reservoir site about 1 mile upstream from the Spangler site that permitted diversion to the Joslyn Ditch at all times was investigated. Reauthorization of the Mann Creek Project, with development of storage at the Yoder site, was recommended with a number of other projects for construction in a basin-pooling plan under which irrigation projects would receive financial assistance from power projects in the Columbia River Basin. The proposals were not adopted by Congress.

A new study was prepared on the Spangler site in 1958, followed by authorization and development of a definite plan.

Authorization

The Mann Creek Project was authorized for construction by the Act of August 16, 1962 (76 Stat. 388, Public Law 87-589).

Project purposes are irrigation, recreation, and conservation and development of fish and wildlife. The recreation purpose is associated with the minimum basic recreation facilities. The fish and wildlife purpose is related to works included for fishery mitigation.

From Bureau of Reclamation