Month: August 2008

Now the state of Washington has a lot of wetlands, and has learned a thing or two (often the hard way) about water management. I wonder what they recommend for managing creeks and streams in urban and rural areas? Check out this report, sent to me by our beaver friend Jake Jacobsen, Watershed Steward of Stillaquamish County. It lists a series of techniques for restoration of streams, channel modification, salmonid spawning gravel, and nutrient supplementation.

Check out technique 8 on the list: “Beaver re-introduction.”

This exhaustive report, offered by the Washington department of Fish & Wildlife (notice the difference already?) documents the postive effects of beavers on waterways;

2. PHYSICAL AND BIOLOGICAL EFFECTS

Successful reintroduction of beaver has demonstrated: 1) an elevated water table upstream of the dam, which in turn improves vegetation condition, reduces water velocities, reduces bank erosion, and improves fish habitat (increased water depth, better food production, higher dissolved oxygen, and various water temperatures), 2) reduced sedimentation downstream of the dam, 3) increased water storage, 4) improved water quality, and 5) more waterfowl nesting and brooding areas. These effects, at the landscape level, influence the population dynamics, food supply, and predation of most riparian1 and aquatic species. Beaver dams on coastal streams increase landscape-scale habitat diversity by creating a unique wetland type for that area.

Beaver ponds can alter water chemistry by changing adsorption rates for nitrogen and phosphorus, by trapping coliform bacteria, and by increasing the retention and availability of nitrogen, phosphorus and carbon1. Beaver-altered streams also cause taxonomic and functional changes in the benthic macroinvertebrate community due to the effects of impoundment and subsequent alteration of water temperature, water chemistry and plant growth. Beaver can also influence the flow regime within a watershed. Beaver ponds can improve infiltration and ground water storage by increasing the area where soil and water meet. Headwaters can retain more water from spring runoff and major storm events and release it more slowly, resulting in a higher water table and extended summer flows. This increase in water availability, both surface and subsurface, usually increases the width of the riparian zone and, consequently, favors wildlife communities that depend on that vegetation. The richness, diversity, and abundance of riparian-dependent birds, fish, herptiles, and mammals can increase as a result. Beaver ponds are important waterfowl production areas and can also be used during migration. In some high-elevation areas of the Rocky Mountains, these ponds are solely responsible for the majority of local duck production

In addition, species of high interest, such as trumpeter swans, sandhill cranes, moose, mink, and river otters, use beaver ponds for nesting or feeding areas3. Beaver ponds also provide very important salmon habitat in western Washington and Oregon. Juvenile coho and cutthroat are known to over-winter in beaver ponds and the loss of beaver pond habitat has resulted in the loss of salmon production potential.

Oh where was all this information when I was writing my part of the subcommittee report? Well, now you know I wasn’t making that stuff up. Just a reminder that our beavers are not available for relocation. You other cities will just have to find your own.

As if all that wasn’t reason enough to invest in the beavers, check out the new prominent campaign issue for Martinez City Council.

.