Walking a stretch of North Creek on a rainy day in September, a red-tailed hawk soared above the North Creek stream valley and new growth of American sycamore, river birch, and tulip poplar. Downstream, the water slowed and widened as it approached a new feature of this restoration project: a beaver dam. Nature’s engineers constructed this dam shortly after Ecotone wrapped up restoration construction in spring of 2020.
North Creek winds through Montgomery Village, a planned community built in the 60’s and 70’s. The stormwater and erosion management structures put in place back then didn’t stand the test of time. Perhaps increased storm intensity in the changing climate, or maybe further modifications in the landscape led to the failures of the stone gabions and rock walls. Either way, North Creek was a prime candidate for restoration when Maryland’s State Highway Administration put out a call for proposals to meet the state’s municipal separate storm sewer system program requirements—a program which will help Maryland fulfill its water quality obligations.
Prior to the 2020 restoration project, eroded banks stood 2-4 feet above the stream and were topped in the thorny invasive multiflora rose. Ecotone’s plan involved re-grading the banks of the creek to reconnect the channel with its floodplain and allow more space for water to spread out, slow down, and sink into the ground during rain events and periods of high water flow. The stone gabions were removed, and woody structures were put in place to restore pool and riffle areas in the stream. Native vegetation was planted along the stream banks and in the floodplain to stabilize soil and support wildlife.
The funny thing about this project is that it already had a beaver dam. Upstream of that dam, water had spread out and slowed down to essentially create a small-scale version of the goal for the entire reach. However, a larger intervention was necessary, and the pooled water had begun to flood a walking path adjacent to the stream. Despite the beaver’s efforts, the dam had to be removed before construction began. One year later, the construction is holding, vegetation is taking off, and the beavers are back.
Looking out on the ponded water resultant of the now three new beaver dams, project manager Mark Magness explains that the stream wasn’t designed to pond as it is, but the beavers have improved the design. Now, with the water merely trickling past the dam, nutrients are cycled through the ecosystem and kept out of the Chesapeake Bay, rainwater filters into the ground, and wildlife like ducks, herons, and frogs have taken up residence, all merely feet from houses, a community center, and a trail that leads to nearby North Creek Lake Park.
It may be the case that this site will again be inundated with water due to the beaver dams, but Ecotone has the knowledge and experience to help Montgomery Villagers continue to coexist with the beaver. “There might be a need for us to install a flow device to regulate the level of the pools and keep the trail above water…this would be the perfect site for it,” Mark said as he surveyed the beaver’s work from above. Ecotone will continue to monitor the site and will be ready to make any further improvements necessary to allow our restoration partner, the beaver, to stay.