COOPERSTOWN, N. Y.

Delaware street sewer

Plans providing for the sewering of Delaware street were approved by this Board September 20, 1900.

is

There is no general sewer system in this village. This plan

r a separate sewer about 2450 feet long which will discharge directly into the Susquehanna river.

PERRY, N. Y.

Separate sewer system

'ans providing for a separate sewer system were approved by tus Board September 20, 1900.

The village lies along the shore and both sides of the outlet of Silver lake, which flows through a steep, narrow and deep ravine for about five miles to its junction with the Genesee river about four miles above Mount Morris.

The contour of the village makes it necessary to discharge the sewage of the two portions divided by the outlet, by gravity, separately. Both of the sewer outlets are below the series of dams on the lake outlet.

Disposal works are to be provided at each outlet at such time as their installation may become necessary. The report of the engineer follows:

ROME, N. Y., September 10, 1900

The President and Board of Trustees, Perry, N. Y.:

Gentlemen-We herewith submit plans and specifications for a complete system of sewerage for the village of Perry.

The plans consist of a general map of the entire village on a scale of 250 feet to the inch, profiles of all of the streets, and

two sheets of details. The general map shows all of the streets of the village with contour lines referred to a point 200 feet below the top of the rail of the Silver lake railroad at the depot, all sewers with their sizes, direction of flow of sewage, grades, manholes, lampholes and flush tanks. The elevation of the sewer invert is shown at all important points and changes of grades. The two points of disposal of the sewage are shown and marked "A" and "B". The profiles show all of the streets of the village with the ground line and depth of the sewer invert, and all sewers with their sizes, rates of grade, and the location of manholes, lampholes, flush tanks, etc. The elevation of the sewer invert is shown at least at every point of change of grade. The detail plans show all the constructions required to be detailed, such as manholes, lampholes, etc., not clearly described by the specifications. The specifications describe and detail the requirements, condition and method of construction of the entire system.

A quantity sheet also accompanies the plans, giving estimated quantities of work and material required on the construction of the entire system in accordance with the specifications.

The following report gives the data upon which the system was designed and reasons therefor:

REPORT

The village of Perry is situated on Silver lake and along both sides of the outlet of the latter. The village as incorporated covers about two and one-half square miles, and has an estimated population of nearly 3000 people. The national census of 1880 gave it a population of 1115, and that of 1890 a population of 1528. We are informed that canvass taken some three years ago of the population gave about 2300, and that since that time the village has had a steady and prosperous growth. The principal manufacturing industries are a file works and a knitting mill, employing nearly 1000 hands. The summer population is somewhat increased due to that portion of the village lying on Silver lake being used to a certain extent as a summer resort and frequented by non-residents.

The village has a water-works system first put into service in the winter of 1896, and the consumption of water is variously estimated at from 400,000 to 500,000 gallons daily as a maximum for all purposes. The water supply is taken from Silver lake and is pumped from a pumping station situated at the foot of the lake road to a standpipe on the lake road hill and thence piped to the consumers. The water from the municipal works is apparently excellent in quality and is generally used for all domestic and other purposes.

Silver lake has a water surface of about two square miles and a tributary drainage area, as taken from the county map, of from 20 to 25 square miles. Its elevation referred to our datum was in June, 1900, 189.7 feet. The outlet of the lake passes through the center of the village of Perry in a ravine which is very narrow and constantly deepening as one proceeds northeasterly to where the outlet passes out of the corporation limits. There are six mill dams on the outlet within the corporation, furnishing a considerable water-power, the average head or fall at each dam being about 20 feet. The mill owners' association have an agreement with the owner of the first or upper water privilege by which he turns into the outlet a certain quantity of water which, from the best information obtainable, varies from 900 to 1100 cubic feet per minute, at certain seasons of the year this quantity being materially increased. The upper privilege controls the level of the lake, using it for pondage. It was principally on account of the above-mentioned dams that it was deemed desirable to empty all sewage below the lower dam.

There are two points of disposal of sewage planned and marked "A" and "B" on the village map. Below the upper one of these "B" the lake outlet channel is narrow, well confined and with a heavy gradient and continues so for miles, or practically to the junction of the outlet with the Genesee river four miles above Mount Morris-Perry being about nine miles from Mount Morris as the outlet and river wind. In addition to the channel being suitable for the disposal of untreated sewage the ravine is very narrow, with banks generally steeper than one horizontal to two

vertical and for a great deal of the distance to the Genesee river nearly if not quite 100 feet high and overgrown with trees and brush. There are scarcely one dozen houses between Perry and the river within 1000 feet of the outlet, most of them being at or near the nearly abandoned settlement of Gibsonville in Livingston county, where once was a developed water-power of some 50 or more feet head. Nowhere, so far as could be learned, is either the outlet or the river below the confluence used for potable purposes.

On account of the great depth of the ravine it would be impracticable except at large expense to unite the two points of disposal into one, even if the conditions required it. The amount of sewage that will ever be disposed of at point "B" will be small, as a special effort has been made to design the system so that as much as possible of the sewage of the village will be emptied at the point "A".

Considering that, after a few years' use of the system the amount of sewage will practically equal the water consumed, and that the population tributary to the sewerage system will eventually increase so that it would be necessary to provide for the carrying of twice the estimated maximum consumption of water as the maximum rate of flow of sewage. The sewer main on Water street has been designed to carry below Hope street this maximum rate of flow of sewage when running one-half full, and this is the capacity of that portion of the line having the least capacity. A considerable quantity of 6-inch pipe is contemplated in the system.

It is only used where extensions are hardly possible and the amount of sewage is and always will be small. Experience has convinced us that when laid with care stoppages occur with very little more if any frequency in 6-inch than in 8-inch pipe. Practically one-half of the system is designed for the use of 8-inch pipe. The table below gives the minimum and maximum capacities in gallons for 24 hours and grades in per cent for the various sizes of pipe contemplated, and also states where the minimum capacity occurs. For the intermediate grades it may

be stated that doubling the grade increases the carrying capacity approximately 50 per cent.

While for 10, 12 and 15 inch sewers an attempt was made to conform in capacity to the estimated requirements, the 6 and 8 inch sewers are generally much larger than a theoretical estimate of the size required to carry the sewage would make necessary, but a further reduction in their size below 6 inches in diameter would render them too small for successful and practicable operation.

For the rates of grade as designed the minimum velocity of the sewage when the sewers are running one-third full will be from 21 to 2 feet per second.

The use of 36 flush tanks is contemplated for the system. They empty automatically and are for the special purpose of flushing the smaller sizes of pipe. The admission of roof water into the sewers is not contemplated, but might be allowed in a few places for flushing the upper ends of the system where there are no flush tanks planned or conected until such time as the use of those sewers would render unnecessary the admission of such roof water. Any permit to connect a roof with the system should contain a clause giving the village the right at any future time. to require the connection to be severed. The admission of roof water might be especially desirable for a time at the few dead ends of the system, or ends having no manholes, lampholes or flush tanks.

There are four separate sheets of profiles. Profile 1 covers all that portion of the village north of Lake street and northwest of the outlet of Silver lake. Profile 2 covers that part of the