The bar chart illustrates the proportions of water levels of reservoirs across six Australian cities in October 2009 and 2010.
Overall, in all cities water levels rose, albeit to varying degrees, except for Perth, which represented a opposite trend. During the first October, Brisbane and Darwin had the most amount of water, whereas Melbourne accounted for the lowest. For the next October, once more, Brisbane showed the highest figure, also presenting the highest increase, while water levels in Perth reservoir declined considerably, holding the least amount of water. Notably, figures remained unchanged in Sydney reservoir.
Turning to reservoirs with considerable changes, Brisbane showed the largest difference, a 25% increase from 75% to 100%, reaching a full capacity. In contrast, Perth witnessed the same level decline from 51% to 26%, making it the least water accumulated reservoir. Over a one-year period, in Canberra water levels rose by 23%, totalling 73% of its maximum capacity.
A closer look at reservoirs with modest variations reveals that in Darwin water volumes increased only by 5%, yet it was second only to that of Brisbane at 80%. Although, the quantity of water in Melbourne reservoir increased to 45% from 35%, it was only higher than Perth. Remarkably, in Sydney water levels stayed the same at 49%.