Some of the Benefits of Beaver Dams
On small flowing trout streams, beaver dams can provide a vital habitat for the resident trout population! The ponds that are created by the damming of the stream channel are important wintering habitats for trout. Also, during the warm summer months, the depth of the ponds can be important cool water retreats for trout, when the thermal temperatures of the flowing stream reach near the upper tolerance for trout.
Beavers are responcible for moving large quantities of bio-mass into the stream system. The rodents use willows and tree cuttings to build their dams and lodges, along with huge food caches in the ponds. This bio-mass inriches the streams nutrient and enhances the invertebrate population, which in turn provides a large amount of food for trout.
The dams created by the beavers are silt trap pools for any large quantities of silt that are moving down the stream system. Over time, this accumulated silt will be converted into stream banks, with nutrient rich soil and a healthy riparian zone. If not for the dams, much of the mobile silt in the system would end up smothering the gravels and cobbles of the stream channel downstream.
Beaver Dams on Small Silt Laden Trout Streams
To help you better understand how beaver dams can benefit the health of a trout stream and enhance the riparian zone, check out the following cross section illustrations of a beaver dam on a small silt laden trout stream, over time:
As you can see, beaver dams can be very beneficial to smaller silt laden trout streams!