ROCHESTER AND ITS WATER WORKS.
FOR completeness in the matter of detail and for throroughness in the way of statistics few men can compete with Chief Engineer Kuichling, of the water works department of Rochester, N. Y., whose annual reports to the commissioners are models of acccuracy and lucid order. In that for the year ending December, 1897, many side lights are incidentally thrown upon the extremely methodical system pursued by the water bureau in that city.
The old and new conduits are both in use, and it may be noticed that each is practically watertight. Every precaution has been taken to make, and keep them so. Each conforms in general to the natural undulations of the land through which it passes,and each is divided into nearly equal sections for convenience of inspection As evidence of the staunchness of the pipe conduit,when certain measurements(described farther on) were undertaken last year for the purpose of determining the difference in level between Hemlock lake and Rush reservoir, both the inlet valve at the reservoir and the intermediate valve, No. 7, which is 10,966 feet distant to the south, were closed as tightly as possible, thus confining the water in this length of the conduit, and exposing its surface, then at rest, in the twenty-four-inch vertical overflow standipe on the summit at West Bloomfield, as weil as in two open piezometer vessels nearby. Says the report:
Obviously any leakage from said length of conduit must cause the water level in these vessels and pipe to fall; and by carefully measuring such fall during a given period of time the rate of leakage is readily determined. During twenty minutes this fall was only 0.267 feet, and, as the aggregate cross-sectional area of the twenty-four-inch pipe and the two vessels is 3.7407 square feet, it follows that the volume lost by breakage in this period was 0.9988 cubic feet, which gives a rate of 6,558 cubic feet, or 49,054 gallons per mile per day. In view of the fact that in this section of the conduit there are five main valves, twenty-four six-inch blow-off valves, and twenty-eight air-valves, from the stuffing-boxes of all of which slight loss of water may be expected, and also that the static water pressure in the lowest part of this section is about 113 pounds per square inch, it may safely be inferred that the pipe is practically watertight.
In order to afford more water, it is proposed to build another distributing reservoir on Cobb’s hill at some future period when the funds admit of it. This must be done sooner or later, as the population of the city is growing apace and the city itself is spreading out over a larger territory. The present population is set down at about 172,000; the city’s area at 11,635, °f which about 10,328 acres are available for general occupation. Within this territory there are 301.38 miles of streets, and 16.31 miles of alleys, and in them an aggregate length of 272.80 miles of water pipes, classed as distributing mains,had been laid up to January 1, 1898. Two distinct systems of pipes are embraced in this aggregate length —the first and most extensive being the general domestic, or Hemlock system, with 254.18 miles of pipe. The second is the Holly system with 18.62 miles of pipe, laid mainly in the central and manufacturing districts. The former is supplied with pure potable water by gravity from Hemlock lake; tbe latter, with impure water by direct pumping from the Genesee river. For the domestic system there are 73.17 miles of eight-inch distributing pipe, and 181.01 of less than eightinch—total 86.22; for thesHolly system, eight-inch pipe, 13.05 less than eight-inch, 5.57—total. 186.58: total number of miles of distributing pipe—domestic system, 254.18, Holly system, 18.62—grand total, 272.80. I’he number of fire hydrants on the domestic system is 2,395; on the Holly system, 295 — total, 2.690; stop-valves in large service pipes— domestic, 2,308, Holly, 250—total, 2,558; sprinkling cart water cranes—domestic, 127, Holly, 125—total 252; drinking troughs for animals—domestic, sixty, Holly, o—total, sixty; meters in use, 6,497; taps in service pipes (approximate) 29,433; regular water accounts (approximate), 27,900; extra water accounts (approximate), 1,533; average consumption of water per capita per day during the year—domestic, sixtythree, Holly eight—total, seventy-one; average consumption per day during the same period in gallons—domestic, 10.770,952, Holly, 1.432,327—total, 12,203,279. Of wrought iron pipe there were In the distributing systems as follows: Domestic, wrought-iron from one-half-inch to three-inch (contents per lineal foot in United States gallons from 0.0102 to o.3′>72) 49,142.48 lineal feet,Holly,oneand three-quarter-inch, 168 linea| feet, 0.032 miles, one-inch, 38.34 lineal feet, 0.007 miles, twoinch, 175.15 lineal feet, 0.033 mile) 379.49 lineal feet 0.072 mile; cast iron—domestic three-inch to thirty-six-inch (contents per lineal foot in United States gallons from 0.3672 to 52.8767) 1.342,054.37 lineal feet, 254.177 miles; Holly (three inch to thirty-six-inch), 98 320.65 lineal feet, 18.620 miles. (From the above in cast iron must be deducted the twentyfour-inch pipes which are in wrought iron and were used as supply pipe from Carroll and Fitzhugh race to pump house, and hence are not properly a part of the distributing system. Dimensions, etc., as follows: Contents per lineal foot in United States gallons, 23,500, Holly, 3.83 lineal feet, 0.640 miles. (In the foregoing is embraced a considerable quantity of small wrought iron pipe which is used for distributing pur poses.) The greater part of this was laid in the past at the expense of private individuals to satisfy urgent demands for water after the annual appropriation for extending the regular cast iron mains had been exhausted. These were to have been, but were not replaced by larger ones, as the localities have not developed sufficiently. Many are probably in bad condition from having been laid so long and will probably be replaced by suitable cast iron pipes. During the year 3.21 miles of pipe, thirty-seven hydrants, and sixty-seven stop-valves were added to the Hemlock distributing system; and 0.25 mile of pipe,one fire hydrant, and fiye stop-valves to the Holly—total of new pipe in both systems. 3 46. Since the closing of the original construction account of the water woiks early in 1876 up to January 1, 1898 the total amount appropriated for extensions of the domestic and the Holly systems was $1,504.50. From the report it is inferred that electrolysis is still doing damage to the water works pipes.
Meters are still being placed on all large service pipes, and the beneficial effects of such a policy, Mr. Kuichling points out,
are plainly evident, not only in the moderate rate of consumption, but also in the comparative uniformity of such rates in the various seasons. From the data afforded by the crude method of gauging the supply, which must be continued until the permanent connections of the new conduit with the two reservoirs are completed, it is found that the daily delivery from Hemlock lake, for the several months of the year ranged from a minimum of io,t86.6oo gallons in September, to a maximum of 11,573.700 gallons in May, w’ith an average of 10,770,950 gallons per day for the entire year. These extreme variations in consumption represent respectively 7.4 per cent above, and 5.4 per cent, below the average,whereas, in cities where meters are not extensively used, such percentages are always very much greater.
The total number of meters and other registering devices in in use on December 31, 1897, was 6,497—an increase of 497 during the year. Of new meters 581 were set—eighty-nine m >re than the increase; but that excess relates to new meters set in place of old ones, and to cases where the use of meters has been abandoned. The causes for the removal of 704 meters, and the number under each head were as follows: Stoppage from accumulation of rust or mud, 169; broken, or defective intermediate gears ot piston rods, cighty-five;broken or defective dial gears, thirteen; broken or defective valves, twelve; injured by frost, seventy-one; injured by hot water or steam, ten; wornout, two; noisy action, thirteen; examination for accuracy after long use, 171; exchanged for meters of larger size, twelve; exchanged for meters of same size, ten; removed because of changing pipes, eight; stopped and needing refitting of piston, ten; sent back to factory on account of inaccuracy, twenty three; leaky stuffing-boxes, seven;removed, owing to vacation of premises, etc., eighty. Concerning the quantity of water taken through these meters, the data at hand relate to meters set in premises, classed as “ manufacturing” and “ commercial ” and to somewhat more than one-half of of the ‘ domestic” meters from April 1,1896, to April 1,1897, and the amount of water used by each of the three classes ot consumers in each month was not computed separately, so that the figures for twelve months stand as follows: From 299 ‘* manufacturing ” meters; 43.fr03.230 cubic feet; from 2,973 “Commercial,” 64,246,402 cubic feet; from 1,669 “ domestic,*’ 43.666,928 cubic feet—total consumption through 4.941 meters 151,516 560 cubic feet—average per month, 12 626, 380 cubic feet. It may be noticed that the “domestic ” meters enumerated embrace all of those which are set in premises where large quantities of water are regularly used, and that the average consumption by meter by the remaining meters of this class Is probably about forty per cent, less than that of the 1,669 set down above. This latter average is 536 2 gallons per meter per day, and if the former is taken at forty percent, less, it will amount to 321.7 gallons per metre per day. Assuming, then, a total of 6,497 meters, of which 3,272 are ” manufactuiing ” and ‘ commercial” and 3,225 are “domestic ”—the lattei being divided into 1,669 of large,and 1,556 of moderate consumption, it will be found that the probable quantity of metered water used every day in Rochester is about 3,606,000 gallons, which is about one-third of the entire average daily supply.
The number of water faucets and appliances of all sorts in metered premises was 83,560; in unmetered, 51.159—total, 197,009 for a population of 172 000.
The water supplied to the eighteen miles of distributing mains of the Holly system is not for drinking purposes in the central and manufacturing districts of the city—incidentally also for supplying hydraulic power to a number of elevators, lift bridges, and small motors, as well as for filling street sprinkling wagons,flushing sewers, etc. In a number of large buildings it is also used for the supply of closets and latrines. The pumping machineiy has a maximum rated capacity of 9,000,000 gallons per day, and can be operated partly by water power and partly by steam power—the latter being used when the river is very low. The boilers, however, cannot furnish steam enough to drive all the pumps; hence the capacity of the works is practically limited to a maximum of about 7,000,000 gallons per day, of which at least one-half, Mr. Kuichling recommends, should be kept in reserve for use during large conflagrations. The engineer in charge of the pumping station states that drafts of over 3,100,000 gallons in twenty-fonr hours have repeatedly occurred in past years; therefore, no further duty should be imposed upon the works in their present state. During the past year the average daily quantity of water pumped for the Holly system was 1,432,327 gallons, with a maximum of 2.337,334 gallons on July 19, and a minimum of 983,595 gallons on February 4, 1897. The greatest monthly pumpage took place in September and the last in February— the daily averages for these two months being respectively, 1,727,327 and 1,170,026 gallons. The difference between these averages is attributable to the operation of the lift bridges over the Eric canai and the use of large quantities of river water for sprinkling the streets and flushing the sewers. These pumpage records have also been computed with an allowance of twelve per cent, slip for the water power engines and seven per cent, for those of the steam engine, which is usually in better condition than the former and has likewise a a considerably lower lift.
Mr. Kuichling recommends the completion of the new conduit at a cost of $60,000; the extension of the large feeding main* of the distributing system at a cost of $133,500; the extension of the ordinary distributing pipes at a cost of $85,000; and betterments at the reservoirs, tepair shop,and pumping station, at a cost of about $6,000.
Mr, Kuichling has given at considerable length an account of the recent gaugings of the two conduits, the results of which, though carried on under unfavorable conditions, were very interesting. The old conduit to Mount Hope reservoir is divided at Hush into two principal sections of the storage reservoir. The southern section—-excluding the thirty-six-inch intake at the lake—embraces 50,807.3 feet, or 9.623 miles, of thirty-six-inch wrought iron riveted pipe made of plates three-sixteenth-inch thick; 15,446.5 feet, or 2,925 miles, of twenty-four-inch wrought iron riveted pipe made of plates three-sixteenths and one-quarter-inch thick; and 36,009.9 feet, or 6.820 miles, of twenty-four-inch cast iron pipe of varying thickness, according to the water pressure; total length is 102,263.7 feet, or 19.368 miles, from the mouth of the pipe in the gatehouse at Hemlock lake to its end in the submerged influent well of Rush reservoir. For the first 7,600 feet, the thirty-six-inch pipe was laid in a relatively deep trench, with a grade of one in about 2,522; for the remainder it conforms.as a rule, to the natural undulations of the land’s surface. The twenty-four-inch pipe lies wholly below a straight grade line, with a fall of 1 in about 381.5 from the end of the thirty-sixinch pipe to the bottom of Rush reservoir. The hydraulic grade lines, however, are somewhat different from these fixed gradients, and are dependent upon both the discharge and depth of water over the ends of the pipe in the reservoir and the gatehouse at the lake. The second connection—tfce northerly.at first consisted of twenty-four inch pipe throughout. It now consists of no feet of thirty-inch cast iron pipe and specials, 46,268 feet of twenty-four-inch cast iron pipe, and 503 of twents-four-inch wrought iron pipe. The section, which in no place rises above a straight grade line, has a fall of 114.4 feet connecting the bottoms of the two reservoirs. After a series of difficult and complicated gauging operations the following results were obtained :
On June 22-23, during a period of 22.5 hours, and on November 9, during a period of 5.5 hours, the discharge from the southern division was at the rate of 6,598,400 and 6,675.900 gallons per day respectively; while on June 23-24, during a period of 22.25 hours, and on November 10, during a period of eight houis, the discharge of the northern division was at the rate of 7,887,800 and 8,153.400 gallons per day respectively. Comparing these figures with the similarly observed discharge of 7,185,000 gallons ptr day for the southern division on October 10, 1890. and that of 8,392.700 gallons per day for the northern division on September 25, 1892, a very marked reduction of delivering capacity, amounting to about one percent, per year on the average, will be noticed in both divisions, which is probably the result of the accumulations of run.sedi nent, and orgmic growths on the interior of the pipe. A fur can also bt made with the gaugings of the southern division, made early in 1875 by the late Mr. L. Nichols, C K. wnich then exhibited a discharge of about gallons per dav, thus showing that such reduction has been progressive or continuous du’ing the whole period of twenty-two vears. Owing to lack of ichable data. not vood c* imate can be made in tegard to the ‘inure rate of thidiminution of flow; but from such ob-ervations ahave been n ade here and elsewhere, it is very probable ’hat it becomes -mailer each year, instead ol increasing.
file new conduit is also in two divisions The southern division comprises 91.554 feet of thirty-eight-ineb liveted steel pipe, and ninety-four feet of thirty-six inch ca*t iron pipe with specials. The northern comprises 48,394 feet of thirty-eightinch riveted steel pipe and t,218 of thirty-six-inch cast iron pipe. In its course is an abrupt turn of ninety degrees near the city line. The results of the tests in the northern line (in the case of which the influence of the few short sections of thirty-six-inch pipe was set asisde) were as follows—the loss of head being observed and arrangements made to observe that separately from open piezometers, and the coefficient c in the Chazy formula and the daily discharge being reckoned in
The amount of cast iron pipe in the northern division being so great,separate observations were made upon 890 feet of thirtysix-inch cast iron conduit and 45,394 feet of riveted steel pipe, with the following results:
The duration of the ten experiments was from seven and three-quarters to nearly sixteen hours each, giving the following values of c: 109. 113, 115, 117, 115, 112, 111, 116, 114, 113. It may be added that gaugings carefully made in 1897 on 46,339 feet of thirty-eight-inch tiveted steel pipe reduced to a considerable extent the value of these results. With respect to those incongruities in value, Mr. Kuichling says that no good reason can be given for them * * * and the results are submitted without further comment, except that they emphasize the necessity of adopting the greatest refinement in making such measurements.
In determining the exact difference in elevation between the two positions of the reference points above the conduit—a distance of twenty miles, the greatest care was exercised, and three lines of levels were run with great care during the last ten years—an attempt being at last made to determine the correct elevations by using the pipe line itself as a leveling instrument. There is an air-valve 9.356 miles from the lake, whose position was such that by closing two gates it was possible for the water in each section to come to rest. From that air-valve a small pipe was earned up the side of the adjoining hill to the bottom of an open vessel in which the water could also come to rest. A diagram was made by plotting close simultaneous observations with barometers and hook gauges at each end of a section. On this diagram were shown not only all the changes and irregularities, but also the true mean elevation of the water surface at each point. After various corrections had been made to allow for errors in the instruments, the result showed the elevation at Rush reservoir to be 248,780, while those found by the earlier levels were 248,370,. 240.330, and 248,550.