760 
PROCEEDINGS OP SECTION II. 
432,000,000 gallons. The above result given is the average of the records 
of the three stations. This quantity flowing in a very dry season, 
expressed in terms of supply for a city, represents more than the 
required quantity for a population of over 5,000,000 persons. I also 
estimated the quantity of fresh water passing down the river during 
the same month (March, 1 892) at about 2,073,000,000 cubic feet. The 
rainfall for that month over the catchment area averaged 2T4 inches 
in depth. This makes the total quantity of rainfall during that month 
about 243,610,000,000 cubic feet. The water discharged in the river 
during the period in question, therefore, only amounts to about *85 
per cent, of the rainfall, showing that in a dry season nearly the whole 
of the rainfall percolates into the ground. 
Since taking these observations, I notice that a gauge has been 
fixed on the river at Yaamba by a Government department, but, as it 
is only intended for navigation records, I am not able to make use of 
the record of river levels for the purpose of calculating the flow 
of water in the river over a more lengthened period, which is very 
desirable. 
NATURAL BY- WASH FOR FLOODS 
In taking observations during the flood of 1800 I noticed the 
interesting fact that this river has a natural by-wash about five miles 
above Rockhampton, where there is a depression in the bank of the 
river on the south side. When the flood waters in the river rise to 
that level they overflow through this depression, and the waters run 
across the country through a chain of lagoons — namely, the Lilymere, 
the Racecourse Lagoon, and the Crescent Lagoon, from which the 
water supply of Rockhampton is taken ; from this they pass on 
through the Yeppen and Serpentine Lagoons, and thence over the 
low-lying alluvial flats of the town common and adjoining country, 
and onward into the river again, and into Keppel Bay, near the river 
mouth, at various points ; thus during extremely high floods the river 
forms a loop round the city of Rockhampton, the lower lands of which 
place only are covered by the flood waters. 
One important point I have noted is the portion of water 
discharged in the ordinary channel of the river and in the natural 
by- wash. The following are approximate records of the waters 
flowing in these channels. The flow in the ordinary river channel 
at Rockhampton during the period of the 1890 flood I estimated as 
follows : — 
Water Flowing. 
Cubic Feet. 
During rise of river up to 4 feet ... ... 137,200,000,000 
„ „ „ 12 „ 118,000,000,000 
„ „ „ 20 „ and upwards 384,800,000,000 
,, falling river ... ... ... ... 172,000,000,000 
Total 812,000,000,000 
I estimated the water discharged by the natural by- wash in the 
following manner : — The approximate section of the flow of this water 
was taken opposite the Crescent Lagoon, which was as follows — 
namely, a portion of the stream about 6 chains wide flowing at the 
