It's known as a flash flood and called that because the water may run for just a single day. It's an event that only happens once or twice a year at the most. The sandy riverbed acts like a giant strip of blotting paper sucking up the water as soon as it appears. But every square metre of soil moistened by this river will increase the chances of survival for those that live here. Waterholes are filled temporarily. Elsewhere in Africa elephants drink every day, but the lack of water here means that desert elephants can only refill their tanks once every four or five days. Within a week the flash flood has produced a flush of green, more than enough to draw the oryx out of the dunes. 它被称为闪电洪水,因为水可能只流一天,而且一年之内最多出现一两次。这些沙漠河床,像一条巨大的吸水纸,水一出现就被它们吸走了,但被这条河流滋润的每一寸土地都会给这里的生存者增加生存机会。水坑装满了水,但只是暂时在非洲的其它地方。大象每天都喝水,但是这里水源缺乏,这就意味着这些沙漠大象只能每隔四五天喝一次水。还不到一周,洪水带来了生机,足以把长角羚引出沙丘。