Beaver Dams and Canals
The ability to control the movement of water has made the beaver play such an important role for many forms of life, most importantly for creating itself a secure environment. By building dams they can raise the water level in a area. When they require more water for another location they will build canals to move the water, create dredge channels to move around freely under water, build plunge holes that start on dry land and will carry underneath a pond and raise up into the beaver lodge or den.
All construction is done at night and the first job when a new family moves into a new area is to build a dam. In some cases the dams will be built in good locations while others in places that do not use the watershed correctly. Research has shown, like humans, beavers gain experience with the older beavers generally building in more resourceful places. Work starts intensely for a few months in early spring and late summer.
The dam base is started by using mud and gravel pushed upwards along the bottom of the stream. If the water is running too fast the beaver will pile sticks fastened into the stream bottom until they forge a base able to hold in place, adding soft vegetation and more mud raising the foundation evenly across the full width. Applying more sticks pushed in strongly, the beaver starts to build a latticework that holds itself in place. The youngest members of the beaver family aid in the construction of the dam. When the dam reaches above water level mud is used to block holes and cement the network of sticks and rocks into water tight structures. Keeping the dam in good shape requires maintenance. Beavers will often inspect the whole dam and if water is leaking the beaver will bring mud up from the bottom and patch or strengthen weak areas.
Beavers build canals for various reasons. Sometimes to link one pond to another or if the family finds a good source of food away from the lodge and wants to use the area they will build a canal to travel safely between the two areas. The beaver creates the canal by starting at a water point and pushing through the soil and vegetation using the forepaws to push materials to the sides and moving rocks away. Canals can be built up to 300 feet long.
Channels are built at the bottom of the ponds and act like a waterway network connecting the lodge to other parts of the living areas, food caches and other dens. Plunge holes can be built under the ground and run up connecting the lodge to dry land. They can be used for reaching food areas