NOTES ON THE RIVER FITZROY, CENTRAL QUEENSLAND. 759 
which drains the southern portion of the catchment area ; the 
Mackenzie Eiver, formed by the junction of the Nogoa and Comet 
Eivers, and which gathers the waters from the western part ; and the 
Isaacs Eiver (with which is united the Connors Eiver), which flows 
through the northern part of the drainage area. These three main 
tributaries unite at a point a little to the north of the township of 
Boolburra, forming the main stream ol‘ the Fitzroy Eiver. 
From tins point of junction the river takes a very circuitous 
course on its way to the ocean, forming a bow, the string of which 
measures about 50 miles in length. It runs first in a north-easterly 
direction fora considerable distance, on its way passing through a gap 
in the Boomer Mountains, then turning to the south-west it follows 
very nearly this direction until it falls into the ocean. 
DIMENSIONS AND CATCHMENT AREA. 
The length of the river, measured from the source of the Dawson 
Eiver branch to the outlet at Keppel Bay, is about 520 miles, including 
bends of the stream. The total length of the river above tidal 
influence is about 450 miles from its rise to the township of Yaamba, 
where the tidal influence ends ; and from the latter place to the sea, 
about 70 miles. 
The catchment area is about 49,000 square miles, which includes 
all the country drained by the river above Eockhampton. As a great 
portion of the gathering-ground of the river is within the Tropics, I 
expected to find the proportion of the rainfall discharged greater than 
in the drier countries of Australia, and this I find to be the case. 
RAINFALL DISCHARGED IN THE RIVER. 
There are, unfortunately, no systematic gaugings of the fresh 
water flowing in the river above the tidal influence. I have, however, 
taken gaugings of the water on a few occasions, and these will give 
an approximate idea of the quantity at the time of my measurements. 
The first estimate of the discharge of the river made by me was during 
the great flood of 1890, when I took the velocities of the stream at 
different periods during the flood and in different positions. I 
estimated the total quantity of water discharged at Eockhampton 
during the months of February, March, and part of April at about 
1.177.000. 000.000 cubic feet. I find the total rainfall over the catch- 
ment of the river during March, 1S90, was 13*47 inches. This rainfall 
over the catchment area of 49,000 square miles gives a. total quantity 
of about 1,523,965,000,000 cubic feet. The water discharged by the 
river during the period in question was about 1,039,000,000,000 cubic 
feet, or about GO per cent, of the whole rainfall on the gathering- 
ground of the river. 
The lowest summer flow which I have observed was in 1 892, when 
I took gaugings at the township of Yaamba, and, as this is just above 
the flow of the tide, it is a favourable position for measuring the 
volume of the fresh water in the river. 
From measurements taken at three stations for observation at 
Yaamba, I estimated the flow at about 67,000,000 cubic feet, or 
420.000. 000 gallons in twenty-four hours. Station No. 1 recorded 
431.000. 000 gallons ; Station No. 2 showed 399,000,000, and No. 3 about 
