Friday, October 24, 2008

Geomorphology/hydrogeology question

Does anyone out there know what the world's largest intermittent river systems are? I'm not looking for wise-ass answers like "Rio Grande". I'm just wondering how common it is to have coherent drainages thousands of km in length that only occasionally carry water.


Anonymous said...

I assume for comparison to Australian rivers. They can't be that uncommon. The arid regions of African and America (North and South) certainly have examples but I couldn't say anything about their size. Are you including rivers that freeze solid? What about rivers that maintain some subsurface flow such as the Gascoyne or Fitzroy?

ScienceWoman said...

Off the top of my head, I'd say that the largest systems are likely to be in Australia. Isn't the Murray-Darling intermittent for most of its length? Or is that entirely anthropogenic?

C W Magee said...

The Murray is only anthropogenically intermittent at the end. Although the snowy mountian scheme actually increases its flow by diverting the upper snowy river through/under the mountains. the Darling, I think, dries up from time to time, but that may also be partly due to irrigation- until a few years ago, they grew a lot of cotton and rice it its headwaters.