Top length, 545 feet; top width, 20 feet; maximum height, 46 feet; slopes, 2-1 and 3-1; hydraulic fill, 69,240 cubic yards, at 10 cents..

Secondary dam "A:"

6,924

Top length, 412 feet; top width, 15 feet; maximum height, 20 feet; slopes, 2-1 and 3-1; earth embankment, 12,000 cubic yards, at 20 cents....

Secondary dam "B:"

2,400

Top length, 700 feet; top width, 15 feet; maximum height, 10 feet; slopes, 2-1 and 3-1; earth embankment, 6,500 cubic yards, at 20 cents.....

Riprap revetment, 9,300 square yards, at 55 cents..

1,300

5,115

Preparing foundation.

1,250

Outlet works:

16,989

Two 30-inch cast-iron pipes incased in concrete; 470 feet cast-iron pipe, laid, at $8..

220 cubic yards concrete, incasing pipe, at $9.50.

3,760

Gates and hoist in place...

2,090

1,000

Right of way.

Engineering

Contingencies, 10 per cent

Total

Capacity of reservoir, 10,195 acre-feet.

Cost per acre-foot, $4.90.

Other reservoir sites in the basin of the Truckee River examined but condemned either on account of their small capacity, relatively high cost, lack of sufficient catchment area, or other sufficient reason, are Webber Lake, Little Truckee No. 2, Stampede Valley, Sardine Valley, Martis Creek, Squaw Valley, Monument Peak, and Grass Lake.

6, 850

4,000

4,000

4,534

49, 973

RESERVOIR SURVEYS IN CARSON RIVER BASIN.

In the basin of Carson River 21 storage sites were examined, of which 4 only are recommended for construction, as follows: Lower Carson, Alkali Flat, Diamond Valley, and Silver King reservoirs. The other sites are Soda Springs, Silver Queen, Berry or Wolf Creek, Heenan Lake, Pleasant Valley, Mud Lake, Long Valley, Prairie, Harveys Meadows, Hope Valley, Charity Valley, Middle Carson, and five smaller ones unnamed. These are condemned as being too small,

FIG. 36.-Cross section of proposed Lower Carson dam, Nevada.

too expensive, or not necessary to the proper control or conservation of the river flow.

During the summer of 1903 a further survey of the Lower Carson reservoir site was made. This work consisted of a traverse of a contour 110.6 feet above the datum of the survey of 1902. The results of this survey have been plotted on the original contour map of the site, and the capacity computed as shown in the following table:

For this reservoir it is proposed to construct a concrete rubble weir dam, having a maximum height of 110 feet above river bed, a top length of 775 feet, and a bottom length of 85 feet.

The outlet will be through a tunnel on the left bank of the river, discharging into the river channel, immediately below.

The water will be admitted to the tunnel through a suitable masonry tower. The estimated cost of this dam is $450,000. The cost of right of way over lands to be flooded will be about $30,000, making the cost per acre-foot of storage capacity $1.68.

CAPACITY AND COST OF RESERVOIRS.

The following table gives the estimated capacity and cost of the reservoirs which have been recommended for construction in the development of the Truckee project:

Capacity and cost of reservoirs in Truckee Basin.