DIVISION RIGHTS

Storage and diversion rights of Talent Irrigation District, which have been perfected and are in good standing, are summarized in table 10.

All unappropriated waters of Rogue River and its tributaries above Raygold were withdrawn by the State engineer under application No. 4496, dated September 6, 1915, for the benefit of future projects then under joint investigation by the State of Oregon and the United States Reclamation Service. Application No. 4497, same date, permits storage of waters mentioned in No. 4496. The withdrawal specifically reserves unappropriated water in the Bear Creek Basin for a Talent Division.

Two additional withdrawals for transmountain diversions from the Klamath River drainage into the Bear Creek basin are:

(a) Application No. 4498, dated September 6, 1915, withdrawing all unappropriated waters of Buck Creek, Beaver Creek, and Keene Creek.

(b) Application No. 4689, dated December 15, 1915, withdrawing all unappropriated waters of Cottonwood Creek, Hungry Creek, Grouse Creek, Long John Creek, and Cow Creek, including their tributaries.

Withdrawals 4498 and 4689 appear to conflict with a withdrawal of all Klamath Basin waters made in 1905 for the benefit of the Klamath project. However, the attorney general of Oregon in November 1950 ruled, in effect, that due to the virtual completion of the Klamath project, the 1905 withdrawal was no longer binding and the State engineer could accept applications and issue permits for Klamath Basin waters.

The State engineer of Oregon in a letter dated November 16, 1953, copy of which is appended, asserts that it has never been considered practical or feasible to divert water of Jenny Creek for irrigation of lands in the Klamath River drainage basin. It is the opinion of the State engineer that water of Jenny Creek should be used for irrigation of lands in the Talent Division and for the storage and development of hydroelectric energy as proposed in this report.

EXISTING USE AGREEMENTS

Medford and Rogue River Valley Irrigation Districts have supplemental rights to Bear Creek waters prior to Talent Irrigation District's rights. The State engineer has ruled, however, that the Talent Irrigation District has priority over the other two districts in recovering, either directly or by exchange with natural runoff, return flows from Talent lands that enter Bear Creek or Medford Irrigation District's Phoenix Canal. The Talent Irrigation District must relinquish such return flows to prior individual water rights.

Talent Irrigation District has contracted with the city of Ashland to deliver 800 acre-feet of water annually to the city limits via Ashland lateral. Any shortage of the district water supply is shared pro rata by the city.

TABLE 10.-Water rights, Talent Irrigation District, Talent division, Rogue River Basin project, Oregon

WATER REQUIREMENTS

Water requirements of Talent Division consist of those for irrigation, power, and contractual obligation to the city of Ashland. Power requirements would be incidental to development of the irrigation supply. There would be no other significant requirements. Historical farm deliveries have not been adequately measured to be of value for water requirement determination.

CONSUMPTIVE USE

Consumptive use was computed from growing season temperatures by the Lowry-Johnson method described in Transactions, American Society of Civil Engineers, October 1942.

Heat units in excess of 32° F. computed from Talent temperature records for the 10 driest years during 1913-45 indicate an annual consumptive use of 2.42 feet. The anticipated division crop distribution is different from that of the projects studied by Lowry and Johnson. Consumptive use was accordingly adjusted to 2.60 feet by weighting the Lowry-Johnson value by an adaptation of the BlaneyCriddle method of consumptive-use determination.

1

Monthly distribution of annual consumptive use was based on evaporation data at Medford, and modified slightly by consideration of heat units at Talent, consumptive-use distribution for units of the Boise and Rio Grande projects, and Blaney-Criddle distribution for Talent Division.

Eighty percent of growing season precipitation was assumed to be effective in meeting consumptive-use requirements. Average growing season precipitation during the 10 driest years was 0.38 foot, of which 0.30 foot was considered effective.

Consumptive-use requirements can be partially supplied from soil moisture available at the start of the growing season. Depletions would be replenished by excess winter precipitation over consumptive use. Estimated soil moisture capacity of division lands is 0.40 foot. Assuming that soil moisture could be depleted 50 percent without impairing crop growth, a growing season draft of 0.20 foot could be sustained.

FARM DELIVERY REQUIREMENT

Farm delivery requirement consists of irrigation consumptive use plus farm losses and waste. Observations of irrigation practices on district lands have indicated that water has been carefully applied, and excessive farm loss and waste is not anticipated. An allowance of 30 percent of the farm delivery for these losses is believed to be adequate. Estimated average farm delivery requirement is shown in table 11.

1 Blaney, Harry F., and Criddle, Wayne E. A Method of Estimating Water Requirements in Irrigated Areas from Climatological Data, Soil Conservation Service, U. S. Department of Agriculture, revised December 1947.

TABLE 11.-Average farm delivery requirement, Talent division, Rogue River Basin

project, Oregon

Soil types and cropping patterns under the various division laterals will affect farm delivery requirements. The division average of 2.61 feet was weighted according to soil types and crops and the farm deliveries for the various laterals are shown in table 12.

TABLE 12.-Adopted farm delivery requirements, Talent division, Rogue River Basin project, Oregon

1 The area under these 2 laterals (427 acres of productive land) is not included in the division.

DIVERSION REQUIREMENTS

Diversion requirements were estimated by adding transit losses and waste to farm delivery. Seepage losses were estimated for each lateral by use of the Moritz formula. Operating waste was assumed to be 5 percent of the diversion for the Ashland lateral and 3 percent for the other laterals. Diversion requirements by laterals are shown in table 13.

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TABLE 13.-Diversion requirements, Talent division, Rogue River Basin project, Oregon