runs through a small valley with a lake in it and enters Puta Creek again about 2 miles below the dam site.

The area of the watershed of this reservoir, estimated from Rice's county map of Lake County, is 91 square miles.

The rainfall in the Cache Creek drainage basin, given by Mr. Chandler in Water-Supply and Irrigation Paper No. 45, has been used as an approximate basis for estimating the rainfall in the Puta Creek Basin, although it seems reasonable to allow a higher average for the Puta Creek Basin, as it has a larger percentage of high mountains within its area.

If the minimum rainfall is 30 inches and the maximum 40 inches, the basin will yield (using J. B. Lippincott's general run-off curve for large watersheds) for the minimum years 30,030 acre-feet, and for the maximum 60,060 acre-feet; so it would take two and one-half seasons of maximum rainfall to fill the reservoir, provided the dam was built to a height of 80 feet. A dam 60 feet high would impound one season's stream flow in years of abundant water supply. If a tunnel 3 miles long should be constructed from Cache Creek, a portion of its water could be impounded in the Guenoc reservoir. (See WaterSupply and Irrigation Paper No. 45, p. 32.) A gaging station has been established near the dam site.

FIG. 8.-Detail of site for wasteway for Guenoc reservoir.

Hammond Hall, State engineer of California, in 1889. Owing to the length of time which has elapsed since that survey was made, it was deemed advisable to have a new survey made of the channel from the outlet of the lake as far downstream as regulating works were contemplated.

CLEAR LAKE RESERVOIR.

Clear Lake, at the head of Cache Creek, is the most important site for a storage reservoir on the west side of Sacramento River. A comprehensive survey was made of this lake and its outlet by William

Three gage rods were set on the lake-one at Lakeport, one at Kono Tayee at the Narrows, and one at Lower Lake at Webbers Landing. Synchronous observations were made at these three stations for fourteen days, thereby establishing an equation for each gage rod. The survey of the lake outlet was connected with the gage rod at Webbers Landing. The result of the readings has not yet been worked out in sufficient detail to allow of the result or the exact equations being given in this report.

Clear Lake has a mean water area of about 40,800 acres. As a reservoir it has an estimated capacity of fully 80,000 acre-feet assured for every irrigating season. It commands the Capay Valley, 20 miles long and from 1 to 3 miles wide, and an area of fine alluvial soil of upward of 75,000 acres in the Yolo Basin. (See Water-Supply and Irrigation Paper No. 45, p. 40.) The survey of the lake outlet made this season was for the purpose of revising the estimates of cost which appear in the paper cited. Measurements of discharge from the lake. are being made at Lower Lake. A gaging station has been established at the mouth of Cache Creek. The record here will show the waste of water into Sacramento Bay. At Lakeport records are kept of the lake level, evaporation and rainfall.

RESERVOIR ON KELSEY CREEK.

A site for a small reservoir was found on Kelsey Creek, about 3 miles above Clear Lake, into which it empties. A reconnaissance survey of this reservoir showed it to have a capacity of about 16,000 acre-feet with a dam 100 feet high. The ground would permit of a dam 150 feet high, the upper 50 feet in elevation more than doubling the capacity, which was estimated to be about 39,000 acre-feet at the 150-foot contour. This would irrigate the land contiguous to Clear Lake as far as Lakeport. Storage in Clear Lake is, however, cheaper and the water may be put upon lands of as great value.

LITTLE INDIAN VALLEY RESERVOIR.

This reservoir, on the North Fork of Cache Creek, has already been described by Prof. A. E. Chandler in Water-Supply and Irrigation Paper No. 45. The reservoir has an estimated annual capacity of 40,000 acre-feet.

STONY CREEK RESERVOIRS.

There are no other storage reservoir sites of value in the Coast Range until Stony Creek Basin is reached. In this basin there are three reservoirs already surveyed and reported on by Burt Cole in Water-Supply and Irrigation Paper No. 86.

Stony Creek, which rises across the divide immediately northeast

of Clear Lake, runs northward for some distance, then turns east, and flows into Sacramento River north of Orland.

The three reservoir sites mentioned above are: First, Briscoe reservoir, on Briscoe Creek, which rises directly in Sheet Iron Mountain; second, East Park reservoir; and, third, Mill Site reservoir. The following table from Water-Supply and Irrigation Paper No. 86 shows the value of these reservoirs as storage basins and their estimated cost.

Cost and capacity of reservoirs on Stony Creek.

A reservoir site in Hambright Valley, near Orland, was examined, but was not considered worthy of a detailed survey. The dam for this reservoir would be very wide, and there is little prospect of reaching solid rock at a reasonable depth. The reservoir has no drainage area, and would have to be filled by a canal from Stony Creek during time of flood. The reservoir basin is not more than 14 miles wide in any direction, and the expensive canal and dam and the small capacity of the reservoir render it of no value.

A small reservoir on Reed Creek, near Paskenta, was also examined, but found to be of little consequence.

Another reservoir was examined on Redbank Creek, 12 miles from Red Bluff. This one has not been mapped. It is of about the same importance as that on Kelsey Creek.

A survey for a reservoir 7 miles above Red Bluff, in the Iron Canyon, has just been commenced, but there has not yet been sufficient work done to give any estimates. It is of great capacity.

RECONNAISSANCE IN BASIN OF PIT RIVER.a

A reconnaissance of Pit River Basin, in Lassen and Modoc counties, was made in order to determine the possibility of storing the waters of this stream in Big Valley.

BIEBER RESERVOIR SITE.

There is a reservoir site at Bieber, Lassen County, which would be of value in connection with the irrigation of the lands of the Sacramento Valley. It may be used to store the winter and spring flow of Pit River for late summer irrigation in the lower portion of its valley. This would assist in obviating the necessity of interfering with the navigation of Sacramento River below Red Bluff by irrigation diversion from that stream during its lower stage.

Big Valley is now adequately irrigated in its lower portions by two diversion canals. One takes water from Pit River near the Lassen County line and the other from Ash Creek near Adin. Some of the lower lands are flooded directly from the river by the diversion of water by weirs and levees. Native grasses constitute the prevailing crops; but some alfalfa and timothy is grown. Excessive amounts of water are used in flooding. The irrigated areas in Big Valley could be materially extended by the construction of high-line canals heading at Stone Coal on Pit River.

It is possible that storage reservoirs would be necessary at Round Valley or Warm Springs Valley to supplement the summer flow available for the reclamation of Big Valley. Practically all of the lands in Big Valley are private holdings.

The dam site for this valley is in the canyon about 7 miles below the town of Bieber. There is a choice of two dam sites; the one, measured near the exit of the valley, is 60 feet wide at water level, 680 feet wide at 50-foot elevation, 880 feet wide at 100-foot elevation. There is no solid rock visible at this site.

About 1,000 feet below the first dam site there is another site where the canyon bends and is considerably narrower, but there is some loss of grade between these points. No section of this site was taken. The rock on both sides is very poor. stream bed and banks of the canyon.

The bed rock crops out in the

The estimated length of this reservoir with a 100-foot dam is about. 15 miles, and the mean width is 2.5 miles. Estimating this area with 30 per cent of the dam height gives (15 by 2.5 by 640 by 30=) 720,000 acre-feet.

A reservoir here would flood the most desirable land for irrigation in the neighborhood. Big Valley is entirely occupied by hay fields, stock raising being the principal pursuit. The value of the land in

a Extract from report of H. E. Green,