aftermath of flood shows silt mound and toppled trees
It is customary to think of the changes wrought on the landscape by wildlife as gradual impacts. For example, the browse line deer make on trees rimming a lake or game trails beaten into the soil and vegetation over decades of travel by hooved and pawed creatures. But sometimes wildlife induced changes can be immediate and dramatic. Such was the case August 11th on the Moose River in the BWCA when a beaver dam on a small tributary burst, releasing thousands of cubic feet of water into the Moose River and creating a flash flood of destructive proportions. The Google satellite photo taken before the dam burst shows the enormity of the beaver pond that drained into the Moose River. I came down the river the following day with a group of nine. Large trees were toppled a big cedar was split. A pile of sandy silt burying debris to a depth of two feet was deposited. Water was turned turbid. Small beaver dams on the Moose River just upstream of Nina-Moose Lake were obliterated. It was not possible to determine exactly what time the dam burst, and whether anyone was on the river at that time or even how catastrophic the surge was. As of early afternoon on Monday, a waterfall created by the tributary was still roaring and evidence on the riverbank indicated that the water level was recently at least 15 inches higher! Although the river had dropped the 15 inches by the time we got there on Monday afternoon, the persistent high water level still made for easy paddling north and even enabled two of our canoes to run the last rapids on the Moose River before it flows into Lake Agnes – usually a 95-rod portage. But life goes on and balance returns. On our return Friday, the waterfall had quieted, the Moose River had subsided to a more typical level, beavers were rebuilding their dams and we waded and blazed a new portage.