=27. Résumé of Method for Determination of Quantity of Dry weather Sewage.=—The steps in the determination of the quantity of sewage are: determine the period in the future for which the sewers are to be designed; estimate the population and tributary area at the end of this period; estimate the rate of water consumption and assume the sewage flow to equal the water consumption; determine the maximum and minimum rates of sewage flow; and finally, estimate the maximum rate of ground water seepage and add it to the maximum rate of sewage flow to give the total quantity of sewage to be carried by the proposed sewers. TABLE 12 DATA ON THE INFILTRATION OF GROUND WATER INTO SEWERS Abstracted from paper by J. N. Brooks in Transactions Am. Society of Civil Engineers, Vol. 76, p. 1909. ───────────┬─────┬──────┬─────┬───────┬──────┬─────┬────────────────────── Place │ │Diam- │ │ │ │ │ │ │ eter │ │ Wet │ Avg. │ │ │ │ or │ │Trench,│ Head │Char-│ │ │Dimen-│ │ Per │ of │acter│ │ │sions │ │Cent of│Ground│ of │ │ │ in │Mate-│ Total │Water,│Sub- │ │Shape│Inches│rial │Length │ Fee │grade│ Gallons per 24 Hours ───────────┼─────┼──────┼─────┼───────┼──────┼─────┼─────┬──────┬───────── │ │ │ │ │ │ │ │ Per │ │ │ │ │ │ │ │ │ Inch │ │ │ │ │ │ │ │ │Diam- │ │ │ │ │ │ │ │ │ eter │ │ │ │ │ │ │ │ Per │ Per │ │ │ │ │ │ │ │Foot │ Mile │ │ │ │ │ │ │ │ of │ of │Per Mile │ │ │ │ │ │ │Joint│ Pipe │ of Pipe ───────────┼─────┼──────┼─────┼───────┼──────┼─────┼─────┼──────┼───────── Boston, │ │ 8 to │ │ │ │ │ │ │ Mass. │Circ.│ 36 │V.P. │ │ │ │ 2.6│ 1,818│ 40,000 East │ │ │ │ │ │ │ │ │ Orange, │ │ │ │ │ │ │ │ │ N. J. │ │ │ │ │ 10│ Q. │ │ │ 22,400 East │ │ │ │ │ │ │ │ │ Orange, │ │ 8 to │ │ │ │ │ │ │ N. J. │ │ 24 │V.P. │ │ │ │ 0.8│ 540│ 8,650 Joint trunk│ │ │ │ │ │ │ │ │ sewer, │ │ │ │ │ │ │ │ │ New │ │ │ │ │ │G. & │ │ │ Jersey │ │ │ │ │ │ Q. │ │ │ 25,000 Rogers │ │ │ │ │ │ │ │ │