Norwich bulletin., 1912-11-30

ing with concrete corewall in the center, extending from two feet below the top of the embankment to tight material. There is considerable amount of rock fill under the down stream paving.
 CorewaII of Concrete.
 The concrete corewaI1 is one and one-half feet wide at the top and two and one-half feet wide at the bottom resting on footing course. The greatest height of the corewall of main dam is 39 feet and it's length is 731 feet. The greatest height of core wall of side dam is 19 feet and it's length is 32O feet.
 Dam 18 Feet Wide on Top.
 The extreme height of the main dam from bottom of lowest footing to top of embankment is 46 feet, and the same dimensions of side dam is 23 1-2 feet The greatest width of main dam is 135 feet and the side dam 73 feet. In each case the width of top is IS feet with slope of two to one on the water side and one and one-haf to one on the downstream side. The spillway is 35 feet long and the abutments five feet high above spill way.
 InCfeaS0o FFSSSuFe ODtalneQs
 The elevation of the spillway is 267 l feet above meantide, or IS 1-2 feet 1 above the Fairview sptllway. This gives an increase of pressure when l Stony Brook reservoir is full of about eight pounds over that due to Fairview | full. The elevation of bottom of sup ply pipe leading to the city is 240 or 27 | feet below full reservoir. The eleva- tion of the bottom of the "A inch waste pipe that discharges into the brook below the dam Is 235 1-2 feet.
 Watershed Area. 1 The watershed has been accurately surveyed and found to be 2.51 square miles, and the watershed and storage i Is considered sufficient to furnish a daily dependable supply of 100000 gallons.
 The area of the watershed in previ- ous calculations has been considered as ? BIO square miles, as this was what the topographic sheets show. A 20 inch venturi meter tube has been installed in the pipe line near the northwesterly corner of Maple wood cemetery, with recording appara- tus.
 Length and Size of Pipe. A q inch pipe starting from the reservoir is used for the supply pipe to the city, diminishing to 16 inches when it has reached the city. The to- tai length of pipe is about four miles
 The length of the pine lines of diff ferent sizes are as follows: "A inch i17,734 feet, including waste pipe; 2 inch, 3,990 feet; 16 inch, 2,S26 feet, in cluding the double 8-inch pipe over thu Central Vermont tracks at West MaiI street for about 30 feet, where ther, was insufficient room for the 16-incl pipe.
 The 16-inch connects with the twt 8-inch pipes with suitable Y branches so that with five or six fire streams 0 250 gallons per minute each passini through the pipe the loss in pressur caused by the reduction in area in s short a length would be exceedingl. small
 Where 20-inch pipe is used there i 12-ineh pipe in the same street.
 Where 16-inch pipe Is used there ar several parallel mains of various size
 in the same and adjacent streets. The Gatehouse.
 The water is sent into the suppl
 pipe through the gatehouse, which ha
 height of 27 feet. with three intak
 levels nine feet apart, the lowest bein
 27 feet below full reservoir. The gate 7 house is reached by single span con , crete bridge 50 feet long, providing three foot wide walk with pipe fro rails each side and a protective fish