Here’s some fun new research out of Poland on beaver influences in streams.
Beaver ponds’ impact on fluvial processes (Beskid Niski Mts., SE Poland)
-Beavers came back to the Carpathian rivers after an over three hundred year absence.
-Beavers’ dam cascade system changed fluvial erosion, transport and sedimentation.
-Beaver activity changed the headwater valley morphology.
-Beaver damming and ponding affect fluvial systems in montane regions.
Abstract
A. Giriata, Elżbieta Gorczycab, Mateusz Sobuckib,
Beaver (Castor sp.) can change the riverine environment through dam-building and other activities. The European beaver (Castor fiber) was extirpated in Poland by the
nineteenth century, but populations are again present as a result of reintroductions that began in 1974. The goal of this paper is to assess the impact of beaver activity on montane fluvial system development by identifying and analysing changes in channel and valley morphology following expansion of beaver into a 7.5 km-long headwater reach of the upper Wisłoka River in southeast Poland.
Two types of beaver dams were noted: in-channel dams and valley-wide dams. The primary effect of dams, investigated in an intensively studied 300-m long subreach (Radocyna Pond), was a change in the longitudinal profile from smooth to stepped, a local reduction of the water surface slope, and an increase in the variability of both the thalweg profile and surface water depths. We estimate the current rate of sedimentation in beaver ponds to be about 14 cm per year. A three-stage scheme of fluvial processes in the longitudinal and transverse profile of the river channel is proposed. C. fiber reintroduction may be considered as another important stage of the upper Wisłoka fluvial system development.
Why does this even matter? Because it means beavers are changing the amount of silt that rivers release whether they have the luxury of expanding into a valley meadow, or whether we’re just talking about a series of dams in a narrow channel, like we had in Martinez. And if you’re not sure that matters check how unhappy Lake Tahoe is about filling up with silt, or how much money cities spend on silt removal.
Remember though this is Castor Fiber, so not our kind of beaver. And people will say we need to study more to learn whether this research applies in America, or Canada or other European countries like Germany, or Amsterdam, or to left handed beavers or beavers that work under full moon. But you get the idea.
Of course this comes as no surprise to us, but it gives me another fine opportunity to post a favorite clip.
I just found something really fun and had to share. How cool would it be to put Mark Poulin’s bright images on these blocks and invite children to make the arch of a healthy creek themselves. And then challenge them to make that same arch WITHOUT THE KEYSTONE.
I found the blocks on a mormon teaching page, (because the use the keystone concept).Then I bought my own set here. I just Mark asked for permission and we can use other images if we need to. If all goes well it could be on the table at Earth day. It would make a dynamic and interactive project that’s really colorful and inviting. You know, Something like this….
