156 HISTORY OF FLOODS IN THE RIVER DARLING. 
old gauge, is 8 feet above the zero of the new gauge. In the 
diagram summer level is the zero, and in all cases the “records by 
the old gauges are use 
The diagram enables us to form some idea of the period for 
which the river is navigable each year, taking the past ten years, 
for which we have measures, and bearing in ‘mind that when the 
water is 4 feet above summer level the river is navigable, it 
appears that during 
1886 it was navigable for...... 6 months 
do do 3 ¥6 
1884 do do 2 eo 
1883 do do Ff #8 
1882 do do 4 re 
1881 do do a Ee 
1880 do do 9 - 
1879 do do 10 ¥y 
1878 do do 8 % 
1877 do do 4 $9 
10 years. LOGAL ccilicesiains 57 months. 
but this is not a statement exactly i in accordance with experience, 
for the river must remain navigable for a sufficient time to allow 
k 
oh interval i short floods had passed down the river, in eac 
which she moved forward a little. These floods are shown 
in the atest as five of the eight little floods in the interval. 
If, then, we leave out of consideration the little floods, there were 
forty months in ten years during which it was navigab e, an 
during this period the river was practically not navigable for 
three years at a stretch, May, 1883, to June, 1886; but a refer 
ence to the diagram will show that during the previous bes 
more favourable, and, I think I shall be able to show you pre — 
reed that the probabilities are that during the next ten years the — 
er will be in a better condition than during the past, although é. 
dey seasons nie always play a conspicuous part in the history ot ~ 
the river Da 
With reference to the diagram, I must explain that prior 
excepting in a few places; but that since that period it 
When first plotted this diagram was made so that the yall : 
followed each other in one line ; but this was ae an 
became necessary to arrange it in som e way. So 
year periods, six years, and various others that have wil si 
gested ; but titan that the only one which gave any indication Of — 
rranged — 
being the right one was nineteen years, and it is therefore a 
a SE aa 
to 
1870 it does not rest upon actual measures of the river hei per’ 
