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on the Genesee can be cared for by the estimated storage capacity. While the floodwaters are storing back of the dam, above the 1,195foot elevation, the spillway ports would be discharging at the maximum 12,000 cubic feet per second; and it has been estimated that a discharge at Rochester of 33,000 cubic feet per second could be permitted without damage. The discharge of 12,000 cubic feet per second from the reservoir would therefore not allow any overflowing of the valley between Mount Morris and Rochester.

In addition to the benefits from flood regulation the foregoing plans would in the ordinary year increase the available water power at Rochester from 9,800 horsepower to 25,370 horsepower and also provide for a 32,000-horsepower plant below the site of the dam at Portage. The river regulation would increase the minimum flow at Rochester from about 200 cubic feet per second in the driest year to 1,180 cubic feet per second. The increase of power at Rochester for the driest year would be 5.9 times the present minimum. Under such a plan the Genesee Basin would become one of the most important centers of water power in the State of New York.

The water-storage commission has made and presented in its annual report for the year 1910 a most interesting study of the effects such a dam as that above described would have on a great flood similar to that which occurred in May, 1909. This flood was the highest in point of volume and flood effect that has occurred during recent years, and it submerged in all about 25,000 acres of land. The peak of the flood was equivalent to a flow of 25,000 cubic feet per second. A study of the situation indicated that a discharge of about 12,000 cubic feet per second at Mount Morris could have been confined to the lower channel without causing any damage to the lower country. When the flow is greater than 12,000 cubic feet per second at Mount Morris, there is usually at the same time a large volume of water discharged into the Genesee by the Canaseraga, its principal tributary, which joins the river below Mount Morris. The combined flow is therefore too great to be carried by the channel when that from above Mount Morris is greater than 12,000 cubic feet per second. The result of the flood of May, 1909, and that which would have taken place had the proposed Portage reservoir been constructed is diagrammatically shown on sheet 1, which is taken from the report of the New York State Water Supply Commission for 1910. The enormous benefits are obvious from an examination of this diagram.

The water-supply commission presents in its last annual report the following estimate of cost of and revenue from the Portage reservoir and power scheme:

Estimated cost of Portage reservoir with dam at the most practicable site
and an intake, pressure tunnel, and power house for power develop-
ment, but without machinery...

Annual fixed charges on the above, including interest and sinking fund......
Estimated gross annual revenue:

$300,000

From power development at the reservoir..
From power improvement at Mount Morris and Rochester.. 115, 000
From river improvement in the Genesee Valley and in the
city of Rochester...

$6, 800, 000

300,000

Net revenue..

35,000

450,000

150, 000

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HUDSON RIVER.

The State Water Supply Commission of New York has conducted surveys in the basin of Hudson River above the mouth of Mohawk River for the purpose of determining the feasibility of developing reservoirs and the effect of such reservoirs on the flow of the stream and on the water powers already established, as well as on the water-power privileges yet undeveloped. The physical conditions on this drainage basin are extremely favorable.At Mechanicsville, N. Y., the total discharge has been known to range from 700 second-feet to 70,000 second-feet, and the average flow is about 8,120 second-feet. Investigations so far made show that 61,000,000,000 cubic feet of storage is the maximum practicable amount that may be developed in the basin. Twenty-nine billion cubic feet can be stored in the proposed Conklingville reservoir on the Sacandaga and 16,000,000,000 cubic feet more can be stored over the Schroon Lake system. The effect on the Hudson is illustrated by accompanying sheet No. 2.

One of the interesting and important features of the effect of this reservoir system is that on navigation in the Hudson. This effect has been studied by the State engineer's office and by the water-storage commission. So important is this feature that the following statement is abstracted from the report of said commission for 1909.

There is sufficient depth of water in the Hudson between New York City and New Baltimore for seagoing vessels. Above New Baltimore a number of low, flat islands divide the river into two or more shallow channels, in which there is a tendency to the formation of troublesome bars. From New Baltimore to Troy, a distance of 20 miles, much dredging has been necessary to maintain an open channel. This dredging was carried on first under State appropriations, supplemented by local contributions. Between 1831 and 1892 the work was done under joint appropriations from the State and National Government. In 1892 a navigable channel, substantially 11 feet deep from New Baltimore to Albany and 9 feet deep at mean low water from Albany to Troy, had been secured. The Federal Government has been engaged in improving the channel since 1898, and the projects provide for a channel 400 feet wide and 12 feet deep from Coxsackie to the foot of Broadway, Troy, and thence to the State dam, for a channel 300 feet wide and 12 feet deep. The estimated cost for this work authorized by Congress in 1898 was $4,344,000, and the total sum expended between 1897 and 1908 for the improvement and maintenance of this portion of the river has been substantially $5,250,000. In 1895 Mr. George W. Rafter, an engineer of wide experience and of good repute, reported to the State engineer of New York that the erection of impounding reservoirs in the upper Hudson of capacity sufficient to provide for a flow of not less than 4,500 cubic feet per second in the Hudson at Mechanicsville will insure an increased depth of water at Albany of 1 feet. This report was made after a careful analytical study of the daily tide records kept by the United States Engineer Department and taking into consideration governing conditions, such as the direction of the wind, the phases of the moon, and the daily volume of flow in the river.

The State water-supply commission has not made any independent investigation of the subject, but a review of Mr. Rafter's work, based

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on his observation, has confirmed his deductions. The commission believes that a broader study of longer term data is necessary, but states that, inasmuch as Mr. Rafter based his judgment on a con

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trolled flow of 4,500 cubic feet per second at Mechanicsville and inasmuch as the establishment of the Sacandaga Reservoir will afford a controlled flow of 6,500 second-feet, or 2,000 second-feet more than

that assumed by Mr. Rafter, it appears reasonable to assume that the increased depth at Albany would certainly not be less than the 14 feet estimated by Mr. Rafter. With respect to this point the commission mentioned that a plan is on foot to secure a 22-foot channel from Hudson to Troy, the cost of which has been estimated at nearly $20,000,000, of which about $7,000,000 would be applied to the river below Albany. On this basis it is evident that the reservoir improvement will proportionately reduce the amount necessary to spend for excavation, in order to achieve the 22-foot channel. The 11-foot depth acquired by reservoir construction would be 15 per cent of the extra depth required for the channel improvement and would probably result in a saving of not less than 15 per cent of the cost of the channel improvement, or about $3,000,000. A liberal estimated cost of the Sacandaga Reservoir is given by the water-supply commission as $4,650,000. Thus it appears that 65 per cent of this cost would be represented by improvements in the navigable portion of the river below Troy, and when it is noted that the reservoir construction would add to the water resources of the immediate region 85,500 horsepower, the benefits of the reservoir project require no further demonstration.

SACRAMENTO BASIN.

Sacramento River is one of the most troublesome flood streams in the United States. Its basin occupies the northern part of California, lying between the Sierra Nevada on the east and the Coast Range on the west. It extends to Mount Shasta, in the extreme northern part of the State, and southward to San Pablo Bay. The tributaries running from the mountain ranges on each side discharge large amounts of water into the main stream during times of excessive precipitation. These waters can not be carried in the normal channel of the river. A large part of the bottom of the valley is made up of great low tracts, called the Colusa, the Yolo, the Yuba, the Sutter, the American, and Sacramento Basins, and become at times of flood a part of the river itself. It has been estimated that 1,250 square miles of the Sacramento Valley are overflowed periodically and 1,700 square miles are overflowed during large floods. The basins comprise some of the best agricultural land of the State and constitute the great body designated as "swamp and overflow land" given to the State of California by the Federal Government under the swamp-land act of 1850.

The reclamation of this land for agriculture constitutes one of the most beneficial works of development in the State of California. From the time the land was given to the State, in 1850, down to the present, numerous plans have been executed for the shutting off of the flood waters of the Sacramento. Levees have been constructed, drainage works excavated, and much of the land is now productive. The grave feature of this reclamation work is that as the great basins have been progressively shut out of the flood plain of the Sacramento, the water which would otherwise flow over them has been more and more closely confined to the established channel of the river, and the flood crests have therefore been raised higher, or the water has inundated other and higher land to a greater extent than would have 36135°-S. Doc. 469, 62-2-10

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