Beavers have inhabited the Dredge Creek system in the Mendenhall Glacier Recreation Area for decades. Their activity can lead to flooded trails and reduced fish passage (particularly coho salmon). Volunteers formed the Beaver Patrol to address these issues, managing beavers’ effects with concern for all parts of the ecosystem. We are a registered nonprofit organization that operates under a Memorandum of Understanding with the U.S. Forest Service, which is in charge of the MGRA.
What do we do? We monitor water flow from the source (not far from the visitor center) to the Mendenhall River, removing dam materials from culverts to keep the water flowing. We’ve built some small fences near culverts to exclude beaver activity. We open notches in some dams, letting water out, to reduce trail flooding or improve fish passage. We may rebuild some dams to restore a pond, after high water or unauthorized human actions tear out major parts of a beaver dam. Among other things, our long-term data provided evidence that the beaver population in the MGRA has not increased in recent years but rather fluctuates around some basic number of active lodges.
Like all management plans, this one is a compromise. Exceptionally heavy rains overwhelm the usual routes for water and trails get flooded—but briefly and less deeply. A sudden spate of dam-building might delay fish passage, but only briefly. Overall, the system continues to function quite well, appreciated by many hikers and dog walkers.
We are looking for new volunteers to work with one or two others for an hour or two once or twice a week. Our active field-work season runs from ice-out (about April) to ice-up (about November). We regularly check culverts, fences, and dams, removing sticks and vegetation as needed. Waders or rubber boots needed. If you can help, meet us in the Forest Service parking lot off the Back Loop at 9 a.m.on Sundays or arrange another time by emailing me (maryfwillson@gmail.com) and we will welcome you.
• Mary F. Willson is a retired ecologist and Beaver Patrol president.
