INVESTIGATIONS IN WASHINGTON.

By T. A. NOBLE.

After a preliminary examination of the various projects proposed in the State of Washington it was decided to concentrate the field. force during the season of 1903 upon two projects, viz, the thorough investigation of the hydrographic and topographic features of the Okanogan project, and a plane-table reconnaissance down the valley of Spokane and Columbia rivers and through the Grand Coulee from below Spokane Falls.

To fully complete the work of investigation in connection with the Okanogan project will require a portion of the field season of 1904. No definite conclusion as to the water supply, capacity of the proposed reservoirs, amount of land that can be irrigated, and cost of construction can be obtained until the records of discharge measurements and other data have been kept for a complete year.

The survey of Green Lake and Brown Lake reservoirs, the canal line from Brown Lake to the irrigable lands, and a survey of a portion of the irrigable lands have been completed.

Gaging stations have been established on Salmon, Sinlahekin, and Johnson creeks. On Salmon Creek the rating curve has been completed. On Johnson Creek the discharge is measured over a weir. The station on Sinlahekin Creek was established too late to complete the rating curve this season. Thirty-six discharge measurements were taken on various private irrigation ditches and at the regular stations on Salmon and Sinlahekin creeks.

The field work on the reconnaissance survey down the valley of Spokane and Columbia rivers through the Grand Coulee has been completed. The excessive cost makes the plan impracticable.

A thorough reconnaissance survey has been made of two other possible plans for diverting the waters of Spokane River onto the arid lands under the Big Bend project. By one plan the water will be carried through one long tunnel and by the other through a series of canals and short tunnels. The preliminary report submitted giving the details of these plans indicates that the cost of this work, though very great would probably not be excessive when the very great area of land that can be irrigated is considered.

In connection with the Big Bend project the following river gaging stations have been maintained: On Priest River, near Priest River,

Idaho; on Pend Oreille River, near Priest River, Idaho; on Little Spokane River, near Spokane, Wash.; on Palouse River, near Hooper, Wash.; on Spokane River, at Spokane, Wash. Discharge measurements of Hangmans Creek and Little Spokane River were made at Spokane by George H. Bliss.

OKANOGAN PROJECT.

AREA TO BE IRRIGATED.

This project contemplates the irrigation of the bench lands in the valley of Okanogan River, in Ts. 32, 33, and 34 N., Rs. 25, 26, and 27 E., of Willamette meridian, in Okanogan County

The land lies in a series of benches, the highest being at an elevation of 1,300 feet, and the lowest, along the river, at 750 to 800 feet. Owing to the very irregular shape of the lands and their varied nature it is impossible to give any accurate estimate of the amount that can be irrigated until a complete map of the area has been made. This map will probably be completed during this field season. All of this land, with the exception of a narrow strip lying along Okanogan River, is too high to be irrigated from the river.

It is believed that, including the unsurveyed townships and the land in Colville Indian Reservation, 40 per cent is public land. Eleven townships have been temporarily withdrawn from entry pending investigation. After the topographic maps of the irrigable area have been completed and the boundaries of the area defined, a large part of the land withdrawn can be restored to entry

WATER SUPPLY.

The streams which have sufficient elevation to irrigate the highest portion of the bench lands are Salmon, Johnson, and Sinlahekin creeks. Salmon Creek flows through the southern portion of the irrigable area and Johnson Creek through the northern portion. Salmon Creek rises in the mountains north and west of Conconully, forming the divide between Methow and Okanogan rivers. The two main branches come together 1 mile south of the town of Conconully. The headwaters are well timbered, mountainous, and covered with a luxurious growth of bunch and pine grass.

Johnson Creek rises from a spring in sec. 26, T. 35 N., R. 25 E. This spring is fed from two small creeks, one flowing from Fish Lake and the other heading at the foot of the hill southeast of Conconully. During most of the year this stream is very constant in volume, being fed almost entirely from springs.

Sinlahekin Creek rises in the mountains north and west of Fish Lake, flows west into the coulee, extending north from Conconully in T. 37 N., R. 24 E., and flows north through this coulee to Similkameen River near the international boundary.