REPORT ON KNOXVILLE WATER SYSTEM IMPROVEMENTS

REPORT ON KNOXVILLE WATER SYSTEM IMPROVEMENTS

DABNEY H. MAURY, C. E.

A report on the Knoxville, Tenn., water works for the purpose of ascertaining what improvements are needed, was recently made to Mayor Hon. S. G. Heiskell, by Dabney H. Maury, G. E., of Chicago, who recommends improvements which would cost $535,000 and include a new pumping station, new reservoir, the adoption of a complete meterage system, four hundred more fire hydrants and additional pumps. In his report Mr. Maury said in part: Attention should be called, at the very outset, to certain defects in the water works plant as a whole which are so fundamental and have so vital an influence upon the present conditions and upon any steps which may be taken to remedy them, that all that may hereafter be said should be considered in the light of these defects. The first of these defects is the division of the territory supplied into two services, high and low, instead of having only one service for all parts of the territory. This grave fault is largely the natural outcome of the way in which the plant has grown. The present twoservice system has resulted in very greatly increased expense in first cost as well as in operation, and in the development of a plant which has become inadequate in practically every department, even for the needs of the present consumers. The next grave defect is that the source of supply is already polluted, and is bound to become more so with the natural growth of the community.

Source of Supply.

The present source of supply is already a dangerous one. About a mile above the intake, Williams Creek enters the river. This is a stream having a water shed oi several square miles and draining a territory on which there is already some suburban and a considerable farming population; as well as a marble quarry, some of. the workmen in which live oil the water shed. Drainage from a number of pig sties and chicken yards also reaches this creek. With commendable foresight the Knoxville Water Company purchased some years ago a very desirable location for a pumping station and filter plant just above Williams Creek, and these lands are now owned by the city, having been transferred with the rest of the water works property when the latter was purchased. The present intake is a strong and substantial one and is in good order. Except that there is some room for improvement in the screens, it is also of good design. The suction well, which fs connected to the intake and is adjacent to the pump pit, is subject to overflow at high water.

River Pumping Station Building.

There are two batteries, each having two return tubular boilers. Two of these boilers, of 175 h. p. each, were put in between two and three years ago. The other two boilers, which are of 125 h. p. each, were installed in 1901. The old boilers are in still fair condition. There are two low-service pumping engines, both being horizontal, triple expansion, direct-acting Worthington pumps. One of these, with a nominal capacity of six million gallons, was installed in 1901; the other, which is rated at ten million gallons, was installed in 1909. These two pumps are the sole reliance of the city for all of its water supply.

High Service Station and Filter House.

This building has substantial masonry walls and is in fair condition, but like the low service station, it has wooden floors and roof, and is in no sense fireproof. There are only two boilers, and of these, one is in fair condition.

There is one horizontal compound condensing Deane steam pump, rated at four million gallons capacity, which is in only fair condition and probably cannot be counted on at present up to its full capacity. There are also two motor-driven single-stage De Laval centrifugal pumps, one of which has a capacity slightly under two million gallons per twentyfour hours, and the other a capacity slightly under six million gallons per twenty-four hours.

Sedimentation and Filter Plant.

The filtration plant originally consisted of a small sedimentation basin and of wooden filter tubs of the old Jewell type. The rated capacity of the filter tubs is three and one-half million gallons per twenty-four hours. In June last, they were being operated at rates w’ ich frequently exceeded seven and one-hal: million gallons, and naturally with poor efficiency, The new concrete Inter tanks, having a rated capacity of three million gallons per day. were then nearly completed and are now doubtless in operation. The new filters which are being constructed by the New York Continental Jewell Filter Company in tile space formerly occupied by the original sedimentation basin appear to be of the usual present standard design of that company, except as to the clear water sump under the pipe gallery and the pump for lilting the water from this sump into the clear water reservoir—these two features being rendered necsary by the fact that the original sedimentation basin was built too low to give the proper head.

Clear Water Reservoir.

This reservoir, which is built in two basins, has a total capacity of about three million gallons, and appears to be in good order. Its capacity is, however, by no means as great as it should be for a daily consumption so large as that of Knoxville. The elevation of the reservoir is, unfortunately, not high enough to provide storage for high service, and when the change is made to the one-service system, this reservoir will be of very little use. These are two in number. The east standpipe, located at the filter plant, is 32 feet in diameter and 85 feet high, with its bottom supported about 25 feet above the ground on a brick tower, and has a capacity of 5lit,000 gallons. This standpipe, as originally constructed, had its base near the ground surface, but some years ago the steel structure was raised in a clever manner by the department’s chief mechanical engineer, this change adding, when the standpipe is full, 25 feet to the head available for high service.

Meters.

The department reports show on January t. 1914, a total of 11,486 service pipes, of which 5,257 were metered. At the end of 1913 a little over 45 per cent, of the services were metered, and that the average per capita consumption for the year 1913, based on the total population supplied, was 136 gallons per day. The consumption averaged for the month of September, 1913, 153 gallons per capita per day, the maximum daily consumption being, of course, considerably larger than either the yearly or monthly average. The records for the first part of 1914 show even higher rates of consumption. This per capita consumption s much larger than it should be. It has been the universal experience with meters that they never prevent consumers from using all of the water that they actually require, and that proper sanitation is encouraged rather than hindered by their introduction. They do, however, prevent waste, and they arc the only effective meeans yet devised for accomplishing this purpose. It is true that the cost of installing meters is considerable, and that there is some added annual expense due to the reading, testing, repairing, and added clerical work in connection with each metered service. The universal introduction of meters would undoubtedly reduce the amount of water consumed in Knoxville from about 140 gallons per capita per day to less than 70 gallons per capita per day. The effect of this reduction would be felt in every single component part of the plant.

Capacity of Present Plant.

As at present arranged and equipped, the plant fails to give proper pressure at certain times to elevated territory, for domestic use alone. It could not of course, at such times, give adequate protection against a large fire, and there is practically no reserve capacity in boilers, machinery, filters, or any other part of the plant, to take care of emergency or breakdowns. Were the consumption to be cut in half by the introduction of meters, lie plant could give fair domestic service to the present population served,’but would still have very little reserve capacity for fires or breakdowns.

Meter Rates.

Glider the sliding scale of meter rates in Knoxville, if is possible for a consumer, simply by wasting more water, to obtain an actual reduction in the amount which he pays. A sliding scale of meter rates is entirely proper, equitable and businesslike; but every consumer, large or small, should pay the same rate for the first water used by him during any month, and obtain the benefit of the reduced rates incident to large consumption, not on the quantity of water to which the first and highest rate applies, but only on the excess above that quantity. It is far more equitable, provided the rates arc properly adjusted, to sell water by meter than by fixture rates. The future expenditures for extensions to the plant would, of course, be enormously reduced; and as the city owns the water works, its citizens must of necessity benefit by any saving or lose by any added expenditure, in connection with the water works system.

Fair Rates.

The proper fundamental basis for rates for water serivce is that the rates, when established, should be fair. Whether the plant be municipally or priaately operated should in no way affect this principle. Before rates may be termed fair, these two conditions must obtain: First. The total yearly receipts from all ssmrces must be just sufficient to provide. (a) Reasonable return on the investment. (b) Legitimate operating expenses, including all proper allowances for depreciation and renewals. Second. Each consumer must pay yearly, for the particular class of service which he receives, his just proportion of the above annual costs. To fulfill the second condition, no service of any sort whatever should be -furnished free. A water works plant ⅛ practically always designed to furnish fire protection as well as water for ordinary uses. Fire protection, whether public or private, should be paid for. Assuming that the department is not to receive pay for service rendered the city, and that the meter rentals now in force are continued, the writer would suggest the following schedule of meter rates: For the first 50,000 gallons used in each month, thirty cents per thousand gallons. For all water used in excess of 50,000 gallons per month, six cents per thousand gallons. Rates for private fire protection, while they are somewhat lower than they should be, might be allowed to remain the same provided that all water furnished, except for the purpose of extinguishing fires, should be paid for at regular meter rates.

Recommendations for Betterments.

A new and absolutely fireproof pumping Station should be constructed on the site owned by the city just north of Williams Creek. At this station, modern boilers and pumping engines, in duplicate, and of high efficiency, should be installed, as well as a modern filter plant. A 30-inch cast iron main should connect this new station with the 24inch, 20-inch and 14-inch mains leading north out of the existing River Station; the high and low service system should be so interconnected as to form one system for the entire territory suppled. A new 7,500,000 gallon reinforced concrete reservoir should be construced on the ridge near the west standpipe; additional mains should be laid; at least 400 additional hydrants and about 100 additional valves should be installed; meters should be set on all services, beginning with the most wasteful water takers, and accompanied by proper charges in meter rates. The fire protection afforded by the improved plant will be fully up to every reasonable requirement of the underwriters, and will, in the writer’s opinion, at least equal the standard recommended in their report.

Estimates.

Pumping station, intake and chimney..* 35,000

The foregoing estimates include nothing for meters, the cost of installing which on all services not already metered is estimated in round numbers at $80,000. This expense should be incurred progressively, at the rate of about $20,000 per year. If it is not practicable to secure the needed funds at once, and it is desired to extend the time of construction, then, having first completed comprehensive plans for all of the proposed improvements, the order in which they should be undertaken should next be settled. It is suggested that the new pumping station, intake,boilers, one of the two pumping engines, the 30-inch force main, some of the more important ‘extensions to the distribution system, and about half of the fire hydrants, be installed first. This should be completed in eighteen months, and would involve a total expenditure of about $200,000. The next step would be to build the new filter plant and install the’second pumping engine. This work would take about eighteen months more, would cost about $220,000, and when completed, would give the city all of the benefits of the single service system. The third and last step would be to install during the ensuing twelve months the reservoir and the remainder of the improvements recommended. Or if it were found impossible to complete all of the work in four years, the time might be somewhat extended.

Summary.

The water works plant is inadequate in almost every vital particular. The division of the distribution system into high and low service is responsible for much of the inefficiency of the plant. The average rate of consumption is at least 140 gallons per day for every man, woman and child in the territory supplied, which is manifestly far too high. The source of supply is polluted and is fast becoming more so. It will cost about $535,000 to obtain a new source of supply, remedy all of the physical defects in the plant, and give Knoxville a water works second to none in any city of her class. It will cost $80,0(H) more to be spent progressively out of earnings to meter all of the unmetered services.

No posts to display