The Passaic Flood of 1903 | Page 4

2 to 3 p. m. .32 3 to 4 p. m. .01 --- Total 6.92
Hourly record of precipitation at Newark observation station, October 8-11, 1903.
Inches.
Oct. 8, 8.25 to 9 a. m. 0.05 9 to 10 a. m. .04 10 to 11 a. m. .00 11 to 12 m. .00 12 m. to 1 p. m. .14 1 to 2 p. m. .72 2 to 3 p. m. .49 3 to 4 p. m. .11 4 to 5 p. m. 1.05 5 to 6 p. m. .45 6 to 7 p. m. 1.20 7 to 8 p. m. .60 8 to 9 p. m. .24 9 to 10 p. m. .24 10 to 11 p. m. .13 11 to 12 p. m. .17 9, 12 to 1 a. m. .29 1 to 2 a. m. .33 2 to 3 a. m. .62 3 to 4 a. m. .29 4 to 5 a. m. .35 5 to 6 a. m. .26 6 to 7 a. m. .13 Oct. 9, 7 to 8 a. m. 0.29 8 to 9 a. m. .69 9 to 10 a. m. .69 10 to 11 a. m. .39 11 to 12m. .20 12m. to 1 p. m. .39 1 to 2 p. m. .28 2 to 3 p. m. .34 3 to 3.25 p. m. .13 11.50 to 11.55 p. m. .01 10, 3 to 4 a. m. .02 7 to 8 p. m. .07 8 to 9 p. m. .09 9 to 10 p. m. .02 10 to 11 p. m. .04 11 to 12 p. m. .04 11, 12 to 1 a. m. .06 1 to 2 a. m. .09 2 to 3 a. m. .03 3 to 4 a. m. .05 4 to 5 a. m. .01 --- Total 11.83
From the above tables it may be seen that the maximum rate of precipitation per hour was 1.38 inches at New York and 1.2 inches at Newark. Comparison of the tables on pages 11 and 12 gives an excellent idea of the intensity of the storm. The amount of water falling in a single storm is nearly equal to the total for June, a month of unusual precipitation.
The average of the total amounts of precipitation recorded at the various stations in the Passaic area is 11.74 inches. These totals are fairly uniform, none of them varying widely from the average. Therefore the figure 11.74 represents a conservative mean for a calculation of total amount of water over the drainage area. Assuming this as the correct depth, the amount of water which fell on each square mile of the Passaic drainage area during the storm was 27,273,000 cubic feet, or for the whole Passaic drainage area over 27,000,000,000 cubic feet, weighing about 852,000,000 tons. This amount of water would, if properly stored, fill a lake with twenty times the capacity of Greenwood Lake, would cover Central Park in New York City, which has an area of about 1.5 square miles, to a height of 645 feet, and, at the present rate of water consumption in the city of Newark, N. J., would supply the city with water for twenty years.
DESCENT OF FLOOD.
HIGHLAND TRIBUTARIES AND CENTRAL BASIN.
A description of the descent of flood waters from the highland tributaries into the Central Basin has been given in Water-Supply Paper No. 88. It has been shown that the lands of the Central Basin are covered even in ordinary freshets, and that in the event of a great flood the waters merely rise higher, being, for the greater extent, almost quiescent, and beyond the flooding of houses and barns and the destruction of crops, little damage is done. In other words, the flood along this portion is not torrential in character.
During the flood of 1903 the water fell so quickly all over this basin, and was collected so rapidly by the small tributaries, that a lake was formed at once which served as a cushion against which the raging torrent of the highland tributaries spent itself without doing extraordinary damage in that immediate region. Bridges which might have been lost in a smaller flood like that of 1902 were actually standing in slack water by the time the mountain torrents appeared in force. These streams caused much destruction higher up in the mountains, but in the Central Basin their energy became potential--a gathering of forces to be loosed upon the lower valley. A discussion of the effects of this will be taken up under the heading "Damages."
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