Can Beavers Help us Rehabilitate our Rangelands?

January 24, 2012 | Water Supply, Restoring Rivers, Clean Water

Daniel Nylen
Sierra Rivers Program Assistant

Before winter set in for the season, we discovered an impressive woody dam on the West Fork Carson River while doing field work in Hope Valley Meadow.  This high elevation alpine meadow sits on the eastern slope of the Sierra Nevada only a stone’s throw from South Lake Tahoe. 

Because of its accessibility, it is an extremely popular destination for hikers, anglers, snowmobilers, and photographers alike, and is probably best known for its spectacular fall colors. 

Here in the Sierra, meadows are our natural reservoirs - they store snow that melts in spring and become havens for fish and wildlife during the parched summer months as they slowly return cool, clean water back to the river.  We want to bring this balance back to one of the most cherished and spectacular meadows in the Sierra. 

Well, some critters don’t seem to want to wait around for our help.  Whether they consciously plan to help the areas where they live, or they charge forward on genetically programmed cruise control, beavers and their impressive engineering feats do more than any other species (besides humans) to alter and shape their surrounding landscape – and often in a beneficial manner.

Watch this video of flooding on the West Fork Carson River due to a beaver dam:

Beaver dams maintain and create wetlands, provide high quality habitat for fish, amphibians, and other wildlife, improve downstream water quality, and slow and spread snowmelt runoff, thereby reducing local flooding, recharging groundwater, and extending water levels in streams in late summer. 

The reintroduction of beavers is even viewed by some as a potential climate change adaptation strategy because of the positive effects they have on streams, meadows and water levels.  Their actions often mimic what one would hope to do to rehabilitate an impacted meadow like Hope Valley – raise the stream channel up closer to the meadow surface so that it can more naturally and frequently spill onto its floodplain during the spring snowmelt. 

In fact, in Argentina, introduced beaver are doing too good of a job creating wetlands.  It’s more a story of dambuilders gone wild. 

Here in the Sierra Nevada, there is debate about the historic geographical range of beavers, and so any sort of reintroduction concept would likely be contentious. 

Yet in Hope Valley, they are starting our work for us.  And it’s always a treat to see them in action and to see the changes in the river landscape as a result of their aquatic escapades!

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