WATER WORKS MEN DISCUSS BIG WATER SUPPLY SYSTEMS
Papers on Large Developments Read and Talked Over at the Philadelphia Convention of the American Water Works Association
THE following are excerpts from the official stenographic report of the 2 p. m. session of the second day (Tuesday, May 16) of the American Hater Works Association’s Convention at Philadelphia. This session was taken up by three long papers and there was comparatively little discussion. Vice-President Cramer was is the chair.
CHAIRMAN CRAMER: The first paper of the afternoon session is
Development of the Schoharie Watershed, Catskill Water Supply, by Mr. J. Waldo Smith.
(Mr. Smith prefaced his paper with a short extempore description of the water supply of New York City, in which he called attention to the fact that “the city never had a real water supply until 1842 when it had a population of about 360,000 people. I doubt if there is a parallel in this country, but up to that date and when it reached that population, it was dependent on local supplies largely from wells and little streams on Manhattan Island, augmented to some extent by water brought in barrels and carts from Long Island and New Jersey. But when they did start on the water supply, they did fairly well for themselves and looked far to the future, because they chose the Croton River as the source of supply which, by excessive development, was capable of supplying over 3,000,000 people, and it was not until after the consolidation of the greater city, about 1900 or 1902, when it became possible to plan a supply, common to the whole city, supplying all the boroughs. The agitation for this supply began about 1897. when a survey was made, and this was followed by a report by Mr. John R. Freeman in 1900. In New York it was five years after this was agitated before anything actually happened, and it was over five years in the case of the Catskill supply. The Catskill plant was approved in 1905; the first water came to New York in 1915 and was generally in the city on January 1, 1917. Since that time it has been drawn on to the fullest extent; in fact from the Catskill system has been drawn a supply exceeding the average flow of the stream as measured in the last 19 years, and this was the most economical way to operate, for the reason that there was other water in reserve that could be taken up at any time. It shows the value of a gravity supply, because the minute the gravity supply was ready, they used all the water they could from that supply and only made up the deficiency from the lower heads, and it also came at a time when coal and pumping expenses were very high, so the fact of using gravity water added several million dollars a ycaf to the saving of the public expenses. This supply was planned to deliver water to all the boroughs of the city of New York. The first increment came entirely from Ksopus Creek, and part of the plan was to secure an impounding reservoir and station known as the Ashokan. The Ashokan reservoir is capable of furnishing about 300.000,000 gallons a day. The project under construction now. the Schoharie, impounding water from about 514 square miles, will furnish another 310.000,000 gallons a day. The first expenditure amounted to somewhere around between $140,000,000 and $150,000,000. This addition, which will double the available supply, will cost about $25.00,000 or $30,000,000. Up to 1917 the city secured all its supply from two principal sources, the westerly part of Long Island. Nassau County and the Croton watershed to the north. The Brooklyn watershed was capable of furnishing about 150 or 170,000.000 gallons a day. and the Croton watershed about 330,000,000 gallons a day. There was also supplied about 20,000,000 a day from the Bronx river. The Catskill plan called for the development of the Esopus and Schoharie watersheds. It was found that enough water could be obtained from the Ksopus and Schoharie, and an aqueduct was constructed running south, crossing the Hudson at Storm King ami down to Croton Lake and then south to the city of New York and under the streets of the city, delivering to the boroughs of the Bronx, Manhattan, Queens and Richmond. The work under consideration now is the Schoharie extension. This is the daily per capita consumption and the dependable yield from all sources. You will see that at times the dependable yield is less than the actual concumption. Of course we got by because we were fortunate in falling on average seasons.” Mr. Smith then presented Ins paper in connection with the slides, and at its conclusion the following questions were asked and answered:
A MEMBER: The stepping of that down stream face, that is because of the great height of the dam?
MR. SMITH: Yes, but it was a case of either that or having an O. G. face, and then of course the water would go down there with tremendous force, and you have to take up the energy somewhere. With a reasonable height, you put in an O. G. face, and it is due in a considerable measure to the great height of the dam.
A MEMBER: I suppose you might extend out a concrete apron to break that ?
MR. SMITH: Well, the topography of the location is not favorable to that.
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Water Works Men Discuss Big Systems
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A MEMBER: I thought possibly the rock was stratified in such a way that it was desirable to protect the downstream rock.
MR. SMITH: If the hydrostatic pressure set up in those streams, I think it would make quite a display.
A MEMBER: Did you take any steps to admit air to the back of the trail ?
MR. SMITH: Yes, that was carefully considered; in those models it was quite interesting to see how that acted; unless they did make provision it would hug in against the steps and then the air would get under and then it would move up. I think the natural practice, with a big quantity of water there will not be very much air behind those sheets when you come to cling in closer to the steps.
THE CHAIR: If there is nothing further, we will pass to the second paper of the afternoon. Mr. O’Shaughnessy is not able to be present and unfortunately the slides have come through without the paper accompanying them. C. G. Hyde, who is familiar with the project, has volunteered to interpret those slides as they are put on the screen. Mr. Hyde.
(Mr. Hyde from memory and simply by the aid of the various slides to prompt him. then gave a very full description of the Hetch Hetchy system of water supply for the city of San Francisco, Cal. The project, he said, “proposes to convey 400,000,000 gallons, or about 600 second feet continuously from the Sierra Nevada Mountains into Almi River watershed, to the city of San Francisco, a distance of about 175 miles. This project was conceived many years ago, and was the subject of a very comprehensive and most illuminating report by John R. Freeman in about 1914 or 1915. Since that time this project has been put under construction as far as the mountain end of the work is concerned. This mountain end of the work involves the construction of the Hetch Hetchy dam and the development of the first unit of power, as I recall it about 55,000 h. p. This power water will be conveyed to San Francisco in a tunnel and in a pressure pipe line. The total length of conduit, as I have stated, being about 175 miles.”
Mr. Hyde then went on to describe the various slides, showing the phazes of the work. In referring to the municipal saw mill Mr. Hyde said: “Here is the municipal saw mill which is producing all the lumber used for camps in the construction of the Hetch Hetchy dam. for all their construction camps and other purposes. One of the interesting features with regard to the Hetch Hetchy River is that they propose to take out from forests which I think are owned by the city, something like two thousand million board feet, and the hauling of this lumber alone will practically pay for the extra cost over and above certain base costs which can be properly charged against the project of the railroad.” Mr. Hyde went very fully into the entire system, describing the various features of construction as they appeared on the screen. There was no discussion of the address. Chairman Cramer thanked Mr. Hyde on behalf of the association.)
CHAIRMAN (RAWER: The next paper on the afternoon program is The Construction of the Loch Raven Dam, by William A. Megraw. (NOTEExcerpts from Mr. Megraw’s paper will be published in a later ISSUE.-EDITOR. )
CHAIRMAN CRAMER: The next paper on the program is by Mr. G. E. Willcomb, Twenty Years’ Filtration Practice at Albany, New York. ( Mr. Willcomb here read abstracts from his paper.) (Note—This paper will, it is expected, appear in a later issue.— EDITOR.)
CHAIRMAN CRAMER: Gentlemen, the paper is before you for discussion and questions.
MR. E. T. CRANCH of Petersburg, Virginia.; I would like to ask Mr. Willcomb if he made any determination of his CO2 content during that operation? Were there any complaints about the water after you adopted the treatment with alum, or did yon see any increase in the corrosion of the service pipes?
MR. WILLCOUB: After we introduced the alum in Albany, the CO2 content in the summer time has risen somewhat; that is, late in August, when the river is very low, the CO2 is about 12 or 15 parts per million and there have been a great many complaints of corrosion in Albany;
I would not say there was a larger number of late than formerly, but there have been several cases where apartment hotels have had serious trouble with corrosion, and now it is the policy of the water works where possible to advise with the owners of tenement buildings ami those who intend to build large apartments, to advise them what kind of pipes to use. and large apartment houses arc adopting brass pipes for their risers. Most of the trouble comes from inferior grades of galvanized pipe. We feel that it should be the policy of the water works to provide a water as far as possible free from Co2, yet it is up to the consumers, as far as they arc able, to provide a better grade of piping. Wc have not introduced any measures as yet for taking out the CO2. That is a part of the contemplated design of future work.
MR. HAZEK: I am very much interested in this history of the Twenty Year operation of this plant. I had somewhat to do with its earlier stages. I have not seen much of it or known much of its operation in the years since it started. When the plant was started, the output was ten or twelve million gallons per day. and the antiquated plant was not quite adequate to handle that. The consumption increased rather rapidly, but did not start out with the consumption it reached soon afterward, and the old water board was starting to put on meters; it was the intention to meter the city, but there was an upheaval in the city government and the old water board was displaced, and those who came in were not interested in meters and that situation has remained up to the present time. Mr. Willcomb spoke of the clogging of the lower part of the filter and the difficulty in maintaining its capacity. That is something that I think always happens sooner or later with old filters of this type, and the means of correcting it are rather well known; they have been applied frequently. There was a case exactly like that at Providence. R. I., where, early in the war, with the development of the war industries, the output of water increased beyond the capacity of the plant and there were various reasons why the plant could not be extended, and they were very much discouraged about it. They had at the time the type of sand washer and sand handling equipment that had been installed in Washington originally. The plant was about the same type and about the same design. As an emergency measure, a new sand washing handling equipment was installed and all the sand was washed through to the bottom in the course of the year, and following that procedure, the capacity of the plant was restored and increased so that all the water that was needed by Providence was easily put through the plant during that year and in the years that followed, and not only that, but the production in cost of sand washing and handling was so great that there was no increase in operating expenses, and as a matter of fact the whole cost of the new installation was absorbed by the sand operating expenses during the war period. The city of Poughkeepsie is another case of treating raw water very similar, in fact almost identical in general character with the water at Albany, and coagulation has been used there, I think, longer than at Poughkeepsie, with a coagulating basin and recently with scrubbers, and the Poughkeepsie plant has kept up its capacity and is putting out water that is a close approximation to spring water at the present time, and it has worked very well.
I think the Poughkeepsie filters are cleaned about once a year; at the present time the preparation of the water is so perfect that scraping once a year is all that is necessary.
MR W. H. LOVSJOY of Louisville, Ky.: I would like to ask Mr. Will comb whether the plans for the future in Albany include slow sand filters?
MR. WILLCOMB: I will say in answer to Mr. Lovejoy’s question that there are really no definite plans for the future in Albany. The State Board of Health has recently made a recommendation in which the slow sand plant is to be combined with the idea of holding it in reserve, but there is no definite decision made at all. Understand there has never been any trouble in getting water straight from the slow sand plan;, that is up to a certain point; the only trouble that has ever been found there has been at certain times due to high temperatures and certain forms of organic penetration, when the demand was greater than the slow sand filters could possibly supply. The introduction of alum is purely an emergency measure and an experiment, and by passing water was purely an emergency, due to the fact that there was no means at that time, due to the fact that the beds were not in good condition, for getting any water except by by-passing.
MR. HAZEN: In other words, they were operating at capacity, hut the capacity was not enough ?
MR. WILLCOMB: Exactly; the whole solution of the problem at Albany is meters: they need meters badly, just as Mr. Hazen brought out in his early report, ami while metering is proceeding, consumption is going right along and the meters are not keeping up with it and the water works officials have been very anxious to push meters, but it has been very difficult to get meters put in, and we are about 48 per cent, metered. There is no reason why Albany could not cut its consumption to 75 or 100 gallons. There is another town north of it. of the same population, whose consumption is below 100 gallons, and there is no reason why Albany could not do the same thing. I he meters would certainly supply Albany with water from any new plant in the future if they were introduced.
CHAIRMAN CRAMER: If there is no further discussion, that closes the afternoon program, and we are now up to the point of arranging for the nomination committee. The officers to be nominated this year are President, Vice-President, Treasurer, Trustee from District No. Trustee from District No. 5. It has been suggested that you get together with the least possible loss of time; that No. 1 district, comprising ;InNew England states, Michigan. Wisconsin and Canada, meet in this corner of the room; that No. 2 district comprising the State of New York, meet in the center of the room, on my left; that No. 2 district, comorising Now Jersey. Pennsylvania and Delaware, meet in the rear of the room on my left: that No. 4 district, comprising Ohio, Indiana and Illinois, meet in the front of the room on my right, and No. 5 dis trict, comprising the District of Columbia. Maryland, Virginia. West Virginia. North and South Carolina, Georgia. Florida. Alabama, Mississippi, Missouri, Tennessee, Kentucky, Arkansas, Oklahoma and Texas, meet at this corner of the room on my right, and that No. 6 district, comprising all other states and territories of the United States and all territories outside of the United States except Canada, meet in the rear of the room. The method of selecting and everything else is outlined on the last page of the program.
The session then adjourned.
(To be continued)