The Amazon carries a large volume of water contributing 20% of global river runoff to the oceans. And has the largest rainfall runoff flood. Despite the large rainfall amounts a high proportion of this is lost to the atmosphere via evapotranspiration of the dense vegetation occupying large areas of the river basin. The highest estimates of runoff are for the period December to April, with lower basin averages occurring from May to August. Interestingly there is a slightly less evaporation occurring during the period May to August. This highlights the connection between evaporation and runoff, because less run off corresponds to a lowering of water available for evaporation.