Hudson River Above Salt Water Influence.

The Hudson River may be used for obtaining an additional supply of water for New York City, if the water is taken from the river above the effects of salt water, which is above Poughkeepsie, and if it is filtered before being delivered into the city reservoirs.

The minimum flow of the river at Poughkeepsie is about 1,500,000,000 gallons daily. In the years from 1879 to 1884, when the rainfall was much below the normal and the flow of the river at times was near the minimum above mentioned, the water at Poughkeepsie was somewhat brackish; and on another occasion this condition is said to have existed at Kingston. It is clear that if 500,000,000 gallons of water are taken daily from the river near Poughkeepsie, the tendency of the salt water to flow up the river is still further increased. During such years of low flow the Poughkeepsie water supply, which is now derived from the river, would be objectionable for use, as well as the water proposed to be furnished for the City of New York.

In 1871 the U. S. Coast and Geodetic Survey made observations between New York and Poughkeepsie regarding the under run of the salt water. Through the kindness of the Superintendent, Mr. Henry S. Pritchett, we have received the following information from Mr. H. L. Marindin, who conducted the tests.

"The influx of sea water by the flood stream was studied by parties in my charge in 1871, by observing the changes in the density of the water at surface and near the bottom, at the times of slacks (turning of current from ebb to flood and flood to ebb); 12 stations were thus occupied, about 5 miles apart.

table, I am

"From knowledge gained while making the observations, and an analysis of the results shown in the of the opinion that traces of diluted sea water can be found, near the bottom of channel, as far as Carthage, 70 miles above Sandy Hook, but that the surface water is practically fresh above Teller's Point."

The results are exhibited in the subjoined tabular statement:

Specific Gravities of Water in the Hudson River At and Below the Surface, Reduced to a Temperature of

60 Degrees Fahrenheit, September, 1871.

To ascertain the relation of this under run to the discharge of the river, we requested Mr. Fuertes, from data furnished by Mr. Rafter, to compute the probable flow of the river at the time of Mr. Marindin's observations. This flow he finds to be about 2,900,000,000 gallons per day. It is not until the minimum flow becomes less than 2,000,000,000 gallons that brackish water may reach Poughkeepsie. The lowest known flow, as above stated, is 1,500,000,000 gallons. Therefore, an artificial increase of this lowest flow to the extent of at least 500,000,000 gallons daily, plus the quantity withdrawn from the river for the City's use, should prevent brackish water from reaching Poughkeepsie.

This can be done by building a system of reservoirs on the tributary streams in the Adirondack Mountains sufficient in capacity to store the flood waters from heavy rains. These waters can afterwards be turned into the river when dry weather approaches.

Mr. George W. Rafter, in his report to us, shows that it is quite feasible to increase the present minimum flow at Poughkeepsie, by the addition of 3,200,000,000 gallons daily from such storage reservoirs, to about 4,700,000,000 gallons per day, and no great difficulties stand in the way of a still larger increase.

This would have the practical effect of forcing the brackish water much further down stream than it is now, should even 1,500,000,000 gallons be withdrawn daily from the river at that point.

The addition of this large quantity of water would in dry weather slightly raise the river level from Troy to below Poughkeepsie and thus be an advantage to navigation. On the upper Hudson River it would greatly increase the present water power. The principal water powers are below Hadley, from which point to tidewater there is a fall of 575 feet. With the increased flow from storage reservoirs above Hadley the available power could be increased by 150,000 horse-power above that which is now available at low water. This increased power would furnish opportunity for large investments of capital for manufacturing purposes, and would add to the population of this State.

The project for securing the additional water from the Hudson River comprises, therefore: 1st, a large increase of the flow of the river in dry weather, between Hadley and the intake; 2nd, an intake for the water as far above Poughkeepsie as will absolutely prevent the pumping of brackish water; 3rd, a pumping plant to lift it to filter beds on sufficiently high lands on the east side of the river, and 4th, aqueducts to carry it to covered reservoirs near the city line, from where it is discharged into the distribution system of the city.

Estimates of cost have been made for a duplicate system; one delivering the water at an elevation of 260 feet above sea level, and the other at 131.5 feet above sea level, or sufficient to discharge into the present reservoirs.

The Hudson River water offers no difficulty in the way of purification. By passing it through properly constructed filter beds, such as have been used extensively in Europe for the same purpose, and now used in Poughkeepsie for its own supply derived from the Hudson, the water can be made clear and healthful. The City of Albany has quite recently put such a plant in service, and its installation resulted in immediately and very materially reducing the typhoid fever death rate of that city.

In September, 1899, a board of water experts, of the City of Philadelphia, after an extended and thorough examination, recommended that city to filter the water of the Schuylkill and Delaware Rivers, instead of seeking a new supply of water from

the Blue Ridge. The Schuylkill water is much more polluted than the Hudson water. The waters of the Allegheny and Ohio Rivers, likewise inferior to that of the Hudson, are to be filtered for the cities of Pittsburgh, Cincinnati and Louisville. The water of the Elbe, in Germany, supplying Hamburg and Altona; of the Thames, in England, supplying London, and the waters supplied to numerous other large cities in different parts of the world, are all more or less polluted by the discharge of sewage. In each of these cases, where the water is now being properly filtered, the death rate from water-borne diseases is very low, and a marked decrease immediately followed the introduction of filters.

The cost of construction, operation and maintenance of the plant are given in the following table:

For a supply of 250,000,000 gallons daily, filtered, delivered 260 feet above sea level at the city line:

Cost of construction.....

$39,725,000.00

Annual cost of interest, operation and maintenance 3.088,000.00 Cost of water, per million gallons, delivered at city

line

33.88

For a supply of 250,000,000 gallons daily, filtered, delivered 131.5 feet above sea level at the city line:

Cost of construction.....

$36,880,000.00

Annual cost of interest, operation and maintenance 2,585,000.00 Cost of water, per million gallons, delivered at city

line

28.33

For a supply of 500,000,000 gallons daily, filtered, to be delivered at the city line, half at elevation 260 feet and half at elevation 131.5 feet above sea level:

Cost of construction......

Annual cost of interest, operation and maintenance Cost of water, per million gallons, delivered at city line

$72.374.000.00 5,546,000.00

30.39

Since it would not be necessary, at the outset, to build the filters and pumping plant for the full capacity, but rather for much smaller quantities, to be extended as necessity demanded, the above estimates of cost of construction and operation indicate an expense greater than would actually be required, by reason of deferred payments for a part of the works.

As this project should also be credited with largely increasing the water power of the upper Hudson River, to the

extent of perhaps 150,000 horse-power, which at $10 would represent a revenue of $1,500,000 per annum, we might reduce the cost given above for furnishing the water at the city line by about one-quarter of the amount.

Inasmuch as the addition of so large a quantity of water during the dry season will increase the depth of the channel for some distance below Troy, the navigation interests will also be benefited by the project.

It might still be added that if the enlargement of the Erie Canal was so arranged that the canal could be fed throughout from Lake Erie, a still further increased flow in the Hudson River could be obtained.

The chief advantages of this Hudson River project are that it furnishes:

The largest available supply of water short of the Great Lakes.

2nd. A water, practically as soft as the Croton supply, and the purity of which can be controlled by filtration.

3rd. A supply, capable of being gradually increased with the growth of the city to the extent of over 1,500,000,000 gallons daily.

4th. The incidental creation of a large water power in the upper Hudson River valley.

Streams in the Catskill Mountains.

Mountain streams are to many persons the most attractive source for a city's water supply. The Catskills, with their limpid brooks and a possibility of bringing their water into the houses of New York City, have, therefore, been frequently mentioned as the best future source.

To make a study of this source we have availed ourselves of existing maps, have had special surveys made of doubtful features and a careful examination of all the essential points. On Esopus Creek and its tributaries eight sites have been chosen by Mr. Fuertes for storage reservoirs. The necessary dams would be from 60 to 95 feet in height and from 500 to 1,670 feet in length. The available capacities of the reservoirs formed by the construction of the dams would be about 27,210,000,000 gallons. The available daily yield from all the reservoirs in dry years he computes at about 150,000,000 gallons.

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