Beaver on the Lower Souris Refuge

Abstract

ful effect upon contour furrows and may increase their efficiency by allowing more water to enter the soil. 4. In contour dikes, their burrows endanger the structure by providing channels in which water may flow through the dike. 5. In stock pond dams, neither species perforated the fill below the freeboard. On the faces of these dams, the burrows of ordii penetrated the fill to a vertical depth of 2 feet, and those of spectabilis to 3 feet. The burrows on the upstream face do not affect the line of saturation but those near the toe on the downstream face