Friday, June 09, 2006

Beavers and humans as groundwater rechargers

We already knew this, but it is still interesting. News from the American Geophysical Union via Eurekalert:
Beavers, long known for their beneficial effects on the environment near their dams, are also critical to maintaining healthy ecosystems downstream. Researchers have found that ponds created by beaver dams raised downstream groundwater levels in the Colorado River valley, keeping soil water levels high and providing moisture to plants in the otherwise dry valley bottom. The results will be published 8 June in Water Resources Research, a journal of the American Geophysical Union.


The researchers suggest that the elevated moisture levels found in soil surrounding the dams would otherwise require water from a very large natural flood, which they estimate as the 200-year flood, to achieve the same expansive water availability to the valley bottom. Additionally, beaver dams built away from natural river channels further redirect water across the valley, enhancing the depth, extent, and duration of inundation associated with smaller floods; they also elevate the water table to sustain plant and animal life during the dry summer season.

People achieve the same results through the use of water catchment systems including dams, swales, and gabions, which are common features of permaculture systems.

1 comment:

Scott A. Meister said...

That makes an awful lot of sense.

I think this has been intuitive knowledge among the farming community for some time. In fact, only recently I was on my uncle's farm in Nebraska, and we took a walk down by the river. He pointed out a couple dams being built, and I asked him if he happened to know why beavers built such things.

He responded by telling me, that some people say that they have the ability to sense an on-coming drought, and will start building dams to save water.

If you think about it, which animal is going to notice first that there is dryness abound? The one gnawing on plant stuff all the time! They will notics different moisture levels in plant material (specifically twigs and branches from the rainmakers we call trees). They also happen to probably be most in tune with water levels in the rivers they call their homes etc. etc.

Me thinks a lot can be learned from doing a little beaver watching.