CITY OF BOSTON. OFFICE OF CITY ENGINEER, CITY HALL, ALDERMAN S. B. STEBBINS, Chairman, Joint Standing Committee on Water: Sir: In answer to the order of the City Council requiring the City Engineer "to make an examination of the facilities for obtaining from Charles River a supply of water for the City of Boston, amounting to "10 million gallons per day for 10 years, until 1884, taken from the river at Newton Upper Falls; "20 million gallons for 10 years, from 1884 to 1894; and 30 million gallons for 10 years, from 1894 to 1904, taken from the river at South Natick ; "40 million gallons for 10 years, from 1904 to 1914; and 50 million gallons for 10 years, from 1914 to 1924, taken from the river at some higher point; "And to make an estimate of the cost, such as will enable the City Council to compare it with the plan for a supply from the Sudbury river," referred to me by your Committee, I desire to respectfully report: Understanding that the object of the order was to obtain merely preliminary and roughly approximate estimates, as a means of judging whether further investigations in this direction should be made, rather than to require an exhaustive examination of the Charles as a source of supply, and further understanding that an early reply was expected, I have had made approximate estimates of the cost of works from such data as were at hand, and such as were given by a few levels, and could be collected in a hasty reconnoissance of the grounds. I desire it to be understood that the estimates are only roughly approximated, and that the schemes of works estimated upon have been hastily devised. The first estimate, or that for Newton Upper Falls, is for a conduit on the line and of the size of that proposed for Sudbury river, carried to the village of Upper Falls, with a force main leading to a point on the river just above the village. It also includes the cost of a large storage basin formed by a dam at South Natick, which, from levels recently taken, it is thought it is practicable to build. Storage basin, including land, Conduit, inlet chambers at reservoirs, etc., Force mains, receiving well, engines, engine foundations and buildings (of a temporary character), Superintendence and contingencies, $625,000 1,100,000 230,000 $1,955,000 195,500 $2,150,500 Lift of engines, 50 feet. In transferring the works to South Natick, it will be necessary to put up a new engine at that place before the old ones at Newton Upper Falls can be adapted to the new lift and moved; hence the works will, from the first, be of capacity to deliver fully 30 millions of gallons. The estimate is for extending the conduit from Upper Falls to South Natick, crossing Charles river on a high level bridge; two force mains, each 1,000 feet long, a new engine, with buildings, foundations, receiving well, etc., of a permanent character. Conduit extension, including land damages, Engine, engine foundations, buildings, receiving well and force mains, altering and moving old engines, etc., Superintendence and contingencies, Cost of transfer, $1,900,000 360,000 $2,260,000 226,000 $2,486,000 The order requires an estimate to be made for a scheme of works to be built after the year 1900, by which the water shall be brought to the city by gravitation. Levels have been taken some 17 or 18 miles above South Natick, measured by the river, and the water at that distance had not sufficient elevation to be brought to the city without pumping. It is evident that the cost of a conduit for such a distance would be large, and that the water-shed above the point where sufficient elevation can be found, would be so small that it would not be advisable to build gravitation works for this source, and as the surveys required for the basis of an estimate for such works would take considerable time, I have not attempted to make one. Unquestionably the conduit would never be carried beyond South Natick. For a supply of 40 million gallons and upwards, a new engine, with foundations, force mains, etc., would be required, the estimated cost of which is about $100,000. The yearly cost of pumping at Newton Upper Falls would be about $2,400 for each million gallons per day, and at South Natick about $1,000. The drainage area of the Charles above South Natick is 150 square miles, and the elevation of the water surface above the present mill dam at that place is a little over 100 feet above mean high tide. JOS. P. DAVIS, |