172 Proceedings, &c, for 1885. 



It was further urged that the culverts were correctly designed for 

 ordinary floods; but that in this case the bursting of several dams 

 above the embankment caused an exceptionally heavy flood. The 

 jury unanimously decided that the culvert was large enough to 

 carry all previous rainfall. 



As to the question of the bursting of the dams, Mr. Morell 

 estimated the flood water from the clam at 235,000 cubic feet. 

 Mr. Simson stated there were dams holding respectively 1,047,000, 

 631,000, and 130,000 cubic feet. These must, however, have been 

 some distance away, as those visible from the railway are only 

 small ones, like cattle dams. Mr. Russell, of the Sydney Observa- 

 tory, stated that in some cases the discharge is only about 1 per 

 cent, of the rainfall. Mr. Whitton stated that he had decided the 

 sizes of all # the culverts on the railway, including the Coota- 

 mundra culverts. He further stated that there was a head of 

 12 feet of water to force the water through the culverts. 



Against this statement Professor Kernot raised the objection 

 that a railway bank should not be made to act as a dam, for no 

 care is taken to render it impervious to water. As to the rain- 

 fail on the day of the accident, Mr. Matthews stated that 4 '00 

 inches fell during the day of the accident and 4*97 on the 24th; 

 and there is a record showing 3*08 of rain on the day of the 

 accident 40 miles to the west, so that the heavy rain would seem 

 to have been very general. 



Professor Kernot's conclusion is that the bursting of the dams 

 was but a small matter in comparison with the natural flood 

 discharge, and that the size of the first and second culverts was 

 quite inadequate; but as a new channel was cut so as to divert 

 the stream from these two, recurrence of the accident will probably 

 be prevented. 



In the discussion which followed, Mr. Steane gave some further 

 details collected from the evidence. 



Mr. Morell stated that the waterway of the culvert where 

 the bank failed was 52*78 square feet; that the velocity of the 

 water through this culvert, with a heading of one foot above the 

 crown, would be 17*6 feet per second. Further, that as the catch- 

 ment area was 21 square miles and the absorption probably 

 70 per cent, of rainfall, this culvert would discharge 2 8 -in. fall 

 per hour. 



Mr. Steane gave as an analogous case the Bendigo Creek, at 

 Sandhurst. The bridge was originally of 5 bays, with waterway 

 of 190 square feet, for catchment of 10,000 ac, the basin being 

 mostly impervious. This caused frequent floods, of from 4 feet 

 to 5 feet, with such rainfalls as -63 inch per hour, as mentioned in 

 his paper on " Rainfall and Flood Discharge." Mr. Steane took 

 the dimensions carefully, and came to the conclusion that the 

 Bendigo Creek culvert would not discharge more than 4100 cubic 



