泛滥之谜 13-英语听力

[00:00.01]But is this the same flood and fertility that sustained Ancient Egypt? [00:05.05]There's no doubt that the White Nile has enough water and nutrients [00:08.33]to completely transform the Sudd. [00:10.69]But the great marsh holds onto its riches. [00:13.38]It soaks up the water like a massive sponge [00:16.49]and the labyrinth of papyrus traps any sediment. [00:21.07]Despite a great influx of water, the flood goes no further North. [00:26.55]The flow of the White Nile out of the Sudd changes little through the year. [00:32.01]Ancient Egypt's desert world relied on the annual flood brought by the Nile. [00:37.74]With it arrived millions of tonnes of fertile soil. [00:42.10]So where did it come from? [00:45.11]The search upstream from Egypt and then up the White Nile stalled at the Sudd. [00:52.05]This branch of the Nile is not the source of the great flood. [00:56.74]But there is an alternative [00:58.91]to return to Khartoum and take a different journey along the Blue Nile.