In theory, it's just a tube and catchment system.

理论上，它只是一个管道和集水系统。

One of them is a simple catchment system powered by bubbles, as in whew.

其中一个方法就是一个简单的集水系统，由气泡驱动，就像这样——呼。

In the 1950s the country had 50,000 rivers with catchment areas of 100 square kilometres or more.

二五年代的时候，流域面积达到一百平方公里甚至更多的河流达到了五万条。

The number of rivers with significant catchment areas has fallen from more than 50,000 in the 1950s to 23,000 now.

重要集水区的河流数量已从50年代的50,000条减至如今的23,000条。

But Dr Samanipour found that in combination they could predict quite accurately the demographic make-up of a sewage plant's catchment area.

但Samanipour博士发现，结合起来看，它们可以相当准确地预测污水厂集水区的口构成。

And that is why 10 companies, led by the Nature Conservancy, created the Nairobi Water Fund-to protect the watershed and catchment areas along rivers that supply water to approximately nine million people in Nairobi.

因此10家公司自然保护协会创立的内罗毕水基金的带领下保护内罗毕大约900万居民生命之源的塔纳河流域和支流地区。