...where would you put a day&#x27;s worth of river water?<p>Random internet search shows that a small river flows at about 1000 cubic feet per second, which is about 30 cubic metres; that&#x27;s three million cubic metres in a day, which is three million tonnes (water is so convenient). The biggest supertankers can carry about 300,000 cubic metres, so you&#x27;d need ten of them...