FLOOD SILT OF THE HUNTER AND HAWKESBURY RIVERS, 197 



at West Maitland when the river was 23 feet above its 

 summer level. According to observations at Raymond 

 Terrace, kindly indicated by Mr. H. A. Hunt, Acting 

 Meteorologist, the flood was at its maximum on the 10th 

 and 11th July, so that the water had receded somewhat, 

 and no doubt at full flood the amount of suspended matter 

 would have been somewhat greater. Mr. Prentice also 

 sent a sample of silt deposited by the flood to which he 

 attaches the following remarks : — 



" The jar contains genuine flood deposit. It comes from 

 near Belmore Bridge, out of a slight depression, in which 

 the water would have been stagnant as the river fell, and 

 down stream from a fence which had arrested practically 

 all debris and vegetation. This deposit would average 

 over 2 inches in thickness, probably 3, and is I consider a 

 fair sample of what the flood deposit would be on land 

 which is covered by real flood waters which either rise and 

 remain motionless, or have a very slight current. The 

 deposit varies every few yards, and fences or slight eleva- 

 tions in the ground, by retarding the current, cause a 

 deposit, in the first place and on the up stream side, of 

 almost raw sand, and then on the down stream side the 

 deposit would be more loamy." 



Analysis of Hunter River Water. 



Parts per 1000. Grains per gallon. 



Total residue = 2*463 or 172*4 



Volatile on ignition = 0*308 „ 21*6 



Fixed residue = 2*155 „ 150*8 



Matter in suspension = 2*182 „ 152*7 



(b) Hawkesbury Flood Waters. 

 Through the courtesy of Mr. H. W. Potts, Principal of 

 the Hawkesbury Agricultural College, samples of water 

 and of silt from the flood waters of the Hawkesbury River 

 were also obtained. The following details are supplied by 



