In Water-Supply Paper No. 88 is given the proportion of flood waters contributed to the Central Basin by each of the tributaries. These figures were computed from the results of gagings maintained for a period sufficient to afford this information within a reasonable approximation. In the case of the storm which resulted in the flood of 1903 it is probable that data referred to can not be safely applied. The flood of 1902 was the result of abundant rains following upon and melting a heavy snow. Weather Bureau records show that neither the depth of the snow nor the amount of subsequent rainfall was uniform, or even approximately so, over the Passaic drainage area. Indeed, so marked was the variation that it was believed that the mean rainfall for all the observation stations on the basin did not bear sufficient relation to observed run-off to allow of any reliable deductions. In the case of the October storm, however, the distribution of rainfall was more nearly uniform, and the run-off from the highland tributaries into the Central Basin must have been proportionately different in amount from that indicated in the upland tributary tables in the report of the previous flood. The data given for the 1902 flood can not, therefore, in the case of the highland tributaries, be applied to the conditions which obtained in the flood of 1903. FLOOD AT MACOPIN DAM. Mr. Morris R. Sherrerd, engineer of the Newark city water board, has furnished flow computations over Macopin intake dam, which is the head of the Newark pipe line. As about 73 per cent of the Pequanac drainage area lies above this intake, the table on page 16 shows roughly an equivalent percentage of the flow contributed by Pequanac River to the Central Basin of the Passaic. In consulting this table it should be borne in mind that the entire run-off of the drainage area above Macopin is about 25,000,000 gallons per day more than the amounts presented in this table. All reservoirs and ponds connected with the conservancy system of the Newark water supply were filled except that at Oakridge, which was about 1.5 feet below the crest of the spillway. _Flow of Pequanac River over Macopin dam, October 7-24, 1903._ [From Newark water department.] Cubic feet. Oct. 8, 6 a. m. to 12 m. 240,600 12m. to 4 p. m. 347,600 4 to 6 p. m. 842,200 8-9, 6 p. m. to 6 a. m. 40,110,000 9, 6 a. m. to 12 m. 51,870,000 12m. to 1 p. m. 15,100,000 1 to 5 p. m. 62,430,000 5 to 10 p. m. 89,040,000 10 to 11 p. m. 19,520,000 9-10, 10 p. m. to 8 a. m. 201,350,000 10, 8 a. m. to 12 m. 75,670,000 12 m. to 6 p. m. 103,650,000 6 to 12 p. m. 73,530,000