Laserfiche WebLink
<br /> <br />values of storm parameters, as tabulated in Appendix <br />E, were consulted in the selection of the cities, for a <br />broad spectrum of the ratio of I-hour to <br />corresponding 24-hour rainfall depth is desired in the <br />verification of the intensity-duration-frequency <br />relationship that for each city investigated is <br />formulated as follows: For Los Angeles, <br /> <br />10.95 log1O {I 000412 TO,588) <br />r = . . . . . . (55) <br />av (td + 1.15)0,5]2 <br /> <br />For Chicago, <br /> <br />60.90 log 10 {I 00,596 TOA04) <br />r = . . . . . . (56) <br />av (td + 9.56)U.~U~ <br /> <br />For Miami, <br /> <br />79.94Iog1O{l00,658 T0.342) <br />r = . .. . . . (57) <br />av (td + 7,24)0.732 <br /> <br />For Houston, <br /> <br />98,2610g1O (100,638 rD.362) <br />r = . . . . . . (58) <br />av (td + 9.30p.798 <br /> <br />For Denver, <br /> <br />50,81 10g1O (1 00,503 TO.497) <br />r = . . . . . . (59) <br />av (td + 10.5)0,838 <br /> <br />For Olympia, <br /> <br />6,30 log1O{l00,667 T0.333) <br />rav = (td + 0,6)0048) <br /> <br />....... (60) <br /> <br />Rainfall intensities calculated by using Eqs. 55 and 60 <br />for various durations and frequencies are tabulated in <br />Tables 6 through 11, respectively, which are then <br />compared with Tables B-2, B-3, B.14, B-15, B-26, and <br />B-32, respectively, in Appendix B. It is found from <br />these comparisons that in most cases the calculated <br />values compatible with data obtained directly from <br />the Technical Paper No. 40. Consequently, the values <br />of the standard storm parameters a 1> bl, and c 1 so <br />determined are judged to be unique and adequate for <br />each location studied. <br /> <br />The values of the parameters a, b, and c for any <br />other cities in the United States can be determined. <br />Data of several major cities appended to this report <br />have been examined and it is found that the <br />parameter values so obtained for most of the cities <br />examined produce as good as, if not better than, <br />rainfall results provided for New York City. However, <br />for simplicity, they are not further discussed herein. <br />It will be interesting to see whether maps with iso-a, <br />iso-h, and iso-c lines can be constructed for the <br />United States. It appears very promising in the light <br />of the limited number of graphs (three isopluvial <br />maps and Fig. 4) being used in the determination of <br />the parameters. To do this, however, is another major <br />task which is beyond the scope of the present study. <br /> <br />26 <br /> <br />