The elevation of the water surface of the creek at a point just north of the N. Y. C. R. R. tracks, the place where it is proposed to discharge the sewage, is at an elevation of 42 feet, with the water about 14 feet deep.

The elevation of the street surface at the intersection of Dawsman and Ellis streets, and also at the intersection of First and Second streets is about 50 feet.

The necessary depth of sewers at these points make it impossible to discharge by gravity into Butternut creek, so that the construction of a receiving well, as above stated, was a necessity for providing a place of discharge at a point where all the sewage could be brought by gravity. This location is outside the residence district and in a locality where it will not be objectionable, as there is not likely to be an increase in the number of dwellings in this vicinity.

The elevation of the sewer at the intersection of Henry and Second streets is 32, discharging into the well at an elevation of 31.60, or about 17 feet below the surface of the ground.

The plan provides for all of the sewage from the westerly slope of the village to be brought southerly through Clark street and across private lands and under the N. Y. C. R. R. Co.'s tracks through a 12-inch tile pipe on a grade of 0.2 per 100 feet to the intersection of First and Burrows streets, and thence through Burrows and Second streets to the receiving well.

The sewage from the easterly slope of the village and north of the N. Y. C. R. R. Co.'s tracks is brought to the intersection of Hartwell and Manlius streets, and thence through a 15-inch tile pipe under the tracks of the N. Y. C. R. R. Co. and on a grade of 0.2 per 100 feet to the intersection of First and Henry streets, and thence, after continuing through Henry street to Second street, where it meets the Second street sewer, it is conducted through a 20-inch tile pipe laid on the same grade for about 100 feet to the receiving well.

The receiving well is designed to be 25 feet in diameter and 25 feet in depth, but as the sewage is discharged about 17 feet below the ground, the available storage in the well will be only about 7 feet, or about 28,000 gallons.

The plan provides for the sewage to be pumped from the receiving well into the effluent well, from which it will run by gravity through a 15-inch outlet pipe for a distance of 5600 feet to the point of discharge in Butternut creek.

Over the well will be constructed a brick gate house 25 feet in diameter, which will contain two 10 h. p. gas engines, the sludge press and tanks for chemicals, when such are required, and such other necessary equipment. Centrifugal pumps in duplicate are provided. These to be placed in the bottom of the well and power to be applied through vertical shafting. Duplicate pumps and engines are provided so as to provide for accident or injury to pump or engines. As the village is considering the question of electric lights it would be an economical arrangement to combine an electric lighting plant with the sewage pumping plant. We estimate that with all the present population connected with the sewer, it will take from three to four hours for the well to fill. One pump will empty the well in about an hour, and an hour's pumping will fill one of the precipitating tanks when the same are required and put into the service.

The plan of disposal works presented is that known as "chemical precipitation." The object of the system is to provide for the removal of the solids and impurities held in solution by the sewage and render the effluent sufficiently clear to turn into a stream. The chemicals used are usually lime, copperas and alumina.

The plans herewith presented call for 4 precipitating tanks, each 15 feet wide, 40 feet long, and 6 feet deep, capacity of about 26,000 gallons each. The plans contemplate the discharge of the mixed chemicals into the receiving well just before the sewage is pumped into the inlet channel.

Upon entering the inlet sewage passes through a series of baffle plates and screens, thus thoroughly mixing the chemicals with the sewage. By means of stop planks and valves the flow can be controlled and diverted into the different tanks when, after precipitation, the effluent is drawn off by means of a swinging effluent pipe with a float and discharged through the pipe into the effluent well, from whence it passes by gravity to Butternut creek.

The sludge or solid part left in the bottom of the tank is thence drawn off through the sludge channel into the sludge pit, from whence it can be conveyed to the sludge press and pressed dry and disposed as fertilizer; or if thought desirable, can be spread upon the adjoining land to dry and then be drawn off by farmers. It is probable that some revenue can be realized from this source. We have measured the flow of water in Butternut creek at low water period and find the flow to be 13,300 gallons per minute, a sufficient quantity of water to accommodate the sewage of from 8000 to 10,000 people without making the water objectionable for anything except domestic use.

In view of the minimum flow in Butternut creek, where it is proposed to discharge the sewage, being as above stated, and that no villages are using this stream as a source of water supply, it is probable that the State Board of Health will not require disposal works to be constructed at the present time.

We also submit herewith a preliminary estimate of the cost of the system in accordance with the plans.

Respectfully submitted.

ALLEN & FARRINGTON

Civil engineers

MAMARONECK, N. Y.

Separate sewer system

Plans providing for a separate sewer system were adopted by this Board December 21, 1900. The Board, however, "reserving the right to at any time require the proper purification of the sewage before its final discharge into the harbor of the village of Mamaroneck as contemplated by the plans."

Mamaroneck harbor forms an indentation of about one mile in the northerly shore line of Long Island sound. The village is located at the innermost part of the harbor, but at a point about

3000 feet from the inshore line the harbor entrance is only 300 feet wide.

As the ebb tides carry off the waters from this inner harborestimated at about 75,000,000 gallons-through this narrow opening, it is believed that all the sewage can be surely carried into the sound, so as to render it harmless, by discharging it only at ebb tide. The engineer's report follows:

MOUNT VERNON, N. Y., October 2, 1900

J. F. HUNTER, M. D., Chairman, Messrs. THEODORE VAN AMRINGE and JOHN D. GOODWIN, Sewer Commissioners of the Village of Mamaroneck:

I also sub

Gentlemen-I submit herewith my report upon the design for a system of sewerage for the village of Mamaroneck. mit the following maps, plans, etc., with the report: General plan, Plate No. 1.

Outlet into Long Island sound, Plate No. 2.

Profiles, Plates Nos. 3 to 9 inclusive.

Disposal works and sewer accessories, Plate No. 10.

Proposal, specifications and contract for the construction of the disposal works.

STATEMENT OF COST OF CONSTRUCTION

In order to have a permanent and established datum to which all elevations should refer I communicated with the United States Coast and Geodetic Survey and with the United States War Department, requesting data as to their established bench-marks in the vicinity of Mamaroneck. I found that the nearest benchmarks which either department had in this vicinity was one located by the United States Coast and Geodetic Survey upon Murray's dock in the village of Larchmont, opposite the residence of Mr. Flagler in the village of Mamaroneck, and distant about one-half mile therefrom. This bench-mark was at an elevation of 2.8 feet above mean high water. With this bench-mark as a basis, a series of bench-marks throughout the village has been established, and all elevations are referred thereto. The datum assumed has been mean high water.

TOPOGRAPHICAL FEATURES

The village of Mamaroneck is situated upon Long Island sound, and the New York, New Haven and Hartford railroad, the main trunk railroad between New York and Boston, passes through the village. The village has an area of about four square miles, and has a water frontage along the shore of Mamaroneck harbor and Long Island sound of about seven miles.

It has extreme diversity of topographical features, extending as it does from the low land adjacent to Long Island sound to the high ridge on the northwest of Mamaroneck avenue.

The Boston post-road, running in a northeasterly direction, divides the village into two sections, the southeasterly section comprising the shore section, and being nearly equally divided by Mamaroneck harbor between Orienta point and Rye Neck.

The post-road at Mamaroneck avenue is nearly a mile distant from the eastern end of Orienta point at the mouth of the harbor. This incision of the harbor into the mainland, with the main portion of the village to be sewered situated upon the innermost portion of the harbor, renders the problem of a sewage outlet more difficult of solution and expensive of construction than would be the case if the village were situated directly upon the sound.

The section of the village lying to the northwest of the postroad is intersected by the Mamaroneck river and its tributaries, the principal one of which is Sheldrake creek. These streams discharge into the Mamaroneck harbor at the intersection of the post-road and Mamaroneck avenue, the tide backing up into the stream for a distance of several hundred feet northwest of the post-road.

Immediately northwest of the railroad the Mamaroneck river diverges to the northeast and drains a watershed of approximately 16 square miles, extending as far north as White Plains and the watershed of the Kensico lakes. Upon this river at the northwesterly boundary of the village are situated the reservoirs of the Mamaroneck water company, which furnishes water to the village of Mamaroneck. This company is controlled by the New