Want Healthy Floodplains and Streams? Want Clean Water? Then Make Room for the Beaver

I’m worried about the beaver.  Here’s why.

Imagine a network of brooks and rivulets meandering through a mosaic of shrubby, sometimes boggy, marshland, purifying water and absorbing high volumes of flow during storm events.  This was a typical low-gradient stream in the valleys of the Lower Susquehanna River Watershed in the days prior to the arrival of the trans-Atlantic human migrant.  Then, a frenzy of trapping, tree chopping, mill building, and stream channelization accompanied the east to west waves of settlement across the region.  The first casualty: the indispensable lowlands manager, the North American Beaver (Castor canadensis).

Beaver Traps
Nineteenth-century beaver traps on display in the collection of the State Museum of Pennsylvania in Harrisburg.  Soon after their arrival, Trans-Atlantic migrants (Europeans) established trade ties to the trans-Beringia migrants (“Indians”) already living in the lower Susquehanna valley and recruited them to cull the then-abundant North American Beavers.  By the early 1700s, beaver populations (as well as numbers of other “game” animals) were seriously depleted, prompting the Conoy, the last of the trans-Beringia migrants to reside on the lower Susquehanna, to disperse.  The traps pictured here are samples of the types which were subsequently used by the European settlers to eventually extirpate the North American Beaver from the Lower Susquehanna River Watershed during the 1800s.

Without the widespread presence of beavers, stream ecology quickly collapsed.  Pristine waterways were all at once gone, as were many of their floral and faunal inhabitants.  It was a streams-to-sewers saga completed in just one generation.  So, if we really want to restore our creeks and rivers, maybe we need to give the North American Beaver some space and respect.  After all, we as a species have yet to build an environmentally friendly dam and have yet to fully restore a wetland to its natural state.  The beaver is nature’s irreplaceable silt deposition engineer and could be called the 007 of wetland construction—doomed upon discovery, it must do its work without being noticed, but nobody does it better.

North American Beaver diorama on display in the State Museum of Pennsylvania in Harrisburg.
North American Beaver diorama on display in the State Museum of Pennsylvania in Harrisburg.  Beavers were reintroduced to the Susquehanna watershed during the second half of the twentieth century.
A beaver dam on a small stream in the Lower Susquehanna River Watershed.
A beaver dam and pond on a small stream in the Lower Susquehanna River Watershed.
Floodplain Wetlands Managed by North American Beavers
Beaver dams not only create ponds, they also maintain shallow water levels in adjacent areas of the floodplain creating highly-functional wetlands that grow the native plants used by the beaver for food.  These ecosystems absorb nutrients and sediments.  Prior to the arrival of humans, they created some of the only openings in the vast forests and maintained essential habitat for hundreds of species of plants as well as animals including fish, amphibians, reptiles, and birds.  Without the beaver, many of these species could not, and in their absence did not, exist here.
The beaver lodge provides shelter from the elements and predators for a family of North American Beavers.
Their newly constructed lodge provides shelter from the elements and from predators for a family of North American Beavers.
Sandhill Cranes Visit a Beaver-managed Floodplain in the lower Susquehanna valley
Floodplains managed by North American Beavers can provide opportunities for the recovery of the uncommon, rare, and extirpated species that once inhabited the network of streamside wetlands that stretched for hundreds of miles along the waterways of the Lower Susquehanna River Watershed.
Great Blue Heron
A wintering Great Blue Heron is attracted to a beaver pond by the abundance of fish in the rivulets that meander through its attached wetlands.
Sora Rail in Beaver Pond
Beaver Ponds and their attached wetlands provide nesting habitat for uncommon birds like this Sora rail.
Wood Duck feeding on Lesser Duckweed in Beaver Pond
Lesser Duckweed grows in abundance in beaver ponds and Wood Ducks are particularly fond of it during their nesting cycle.
Sandhill Cranes feeding among Woolgrass in a Beaver Pond
Beaver dams maintain areas of wet soil along the margins of the pond where plants like Woolgrass sequester nutrients and contain runoff while providing habitat for animals ranging in size from tiny insects to these rare visitors, a pair of Sandhill Cranes (Antigone canadensis).
Sandhill Cranes feeding among Woolgrass in a floodplain maintained by North American Beavers.
Sandhill Cranes feeding among Woolgrass in a floodplain maintained by North American Beavers.

Few landowners are receptive to the arrival of North American Beavers as guests or neighbors.  This is indeed unfortunate.  Upon discovery, beavers, like wolves, coyotes, sharks, spiders, snakes, and so many other animals, evoke an irrational negative response from the majority of people.  This too is quite unfortunate, and foolish.

North American Beavers spend their lives and construct their dams, ponds, and lodges exclusively within floodplains—lands that are going to flood.  Their existence should create no conflict with the day to day business of human beings.  But humans can’t resist encroachment into beaver territory.  Because they lack any basic understanding of floodplain function, people look at these indispensable lowlands as something that must be eliminated in the name of progress.  They’ll fill them with soil, stone, rock, asphalt, concrete, and all kinds of debris.  You name it, they’ll dump it.  It’s an ill-fated effort to eliminate these vital areas and the high waters that occasionally inundate them.  Having the audacity to believe that the threat of flooding has been mitigated, buildings and poorly engineered roads and bridges are constructed in these “reclaimed lands”.  Much of the Lower Susquehanna River Watershed has now been subjected to over three hundred years-worth of these “improvements” within spaces that are and will remain—floodplains.  Face it folks, they’re going to flood, no matter what we do to try to stop it.  And as a matter of fact, the more junk we put into them, the more we displace flood waters into areas that otherwise would not have been impacted!  It’s absolute madness.

By now we should know that floodplains are going to flood.  And by now we should know that the impacts of flooding are costly where poor municipal planning and negligent civil engineering have been the norm for decades and decades.  So aren’t we tired of hearing the endless squawking that goes on every time we get more than an inch of rain?  Imagine the difference it would make if we backed out and turned over just one quarter or, better yet, one half of the mileage along streams in the Lower Susquehanna River Watershed to North American Beavers.  No more mowing, plowing, grazing, dumping, paving, spraying, or building—just leave it to the beavers.  Think of the improvements they would make to floodplain function, water quality, and much-needed wildlife habitat.  Could you do it?  Could you overcome the typical emotional response to beavers arriving on your property and instead of issuing a death warrant, welcome them as the talented engineers they are?  I’ll bet you could.

Photo of the Day

Wildflower Meadow Project underway at East Donegal Riverfront Park
Here’s something to look forward to in the new year.  The good citizens of East Donegal Township in Lancaster County have partnered with Alliance for the Chesapeake Bay to establish an extensive wildflower meadow on what had been a mowed field of turf grass at Riverside Park in the Susquehanna floodplain near Marietta.  As the photo shows, the lawn plants have been eliminated in preparation for seeding with a diverse assortment of native grasses and wildflowers to provide habitat for birds and pollinators including butterflies, bees, and other insects.  Once established, the meadow’s extensive vegetative growth will help reduce stormwater runoff by better infiltrating rainfall to recharge the aquifer.  During flood events, the plantings will provide soil stabilization and increase the ability of the acreage to uptake nutrients, thus reducing the negative impact of major storms on the quality of water in the river and in Chesapeake Bay.  Check the project’s progress by stopping by from time to time in 2024!

The Value of Water

Are you worried about your well running dry this summer?  Are you wondering if your public water supply is going to implement use restrictions in coming months?  If we do suddenly enter a wet spell again, are you concerned about losing valuable rainfall to flooding?  A sensible person should be curious about these issues, but here in the Lower Susquehanna River Watershed, we tend to take for granted the water we use on a daily basis.

This Wednesday, June 7,  you can learn more about the numerous measures we can take, both individually and as a community, to recharge our aquifers while at the same time improving water quality and wildlife habitat in and around our streams and rivers.  From 5:30 to 8:00 P.M., the Chiques Creek Watershed Alliance will be hosting its annual Watershed Expo at the Manheim Farm Show grounds adjacent to the Manheim Central High School in Lancaster County.  According to the organization’s web page, more than twenty organizations will be there with displays featuring conservation, aquatic wildlife, stream restoration, Honey Bees, and much more.  There will be games and custom-made fish-print t-shirts for the youngsters, plus music to relax by for those a little older.  Look for rain barrel painting and a rain barrel giveaway.  And you’ll like this—admission and ice cream are free.  Vendors including food trucks will be onsite preparing fare for sale.

And there’s much more.

To help recharge groundwater supplies, you can learn how to infiltrate stormwater from your downspouts, parking area, or driveway…

Urban Runoff
Does your local stream flood every time there’s a downpour, then sometimes dry up during the heat of summer?  Has this problem gotten worse over the years?  If so, you may be in big trouble during a drought.  Loss of base flow in a stream or river is a sure sign of depleted groundwater levels in at least a portion of its drainage basin.  Landowners, both public and private, in such a watershed need to start infiltrating stormwater into the ground instead of allowing it to become surface runoff.
Rain Garden Model
You can direct the stormwater from your downspout, parking area, or driveway into a rain garden to help recharge the aquifer that supplies your private or public well and nearby natural springs.  Displays including this model provided by Rapho Township show you how.

…there will be a tour of a comprehensive stream and floodplain rehabilitation project in Manheim Memorial Park adjacent to the fair grounds…

Legacy Sediments
Have you seen banks like these on your local stream?  On waterways throughout the Lower Susquehanna River Watershed, mill dams have trapped accumulations of sediments that eroded from farm fields prior to the implementation of soil conservation practices.  These legacy sediments channelize creeks and disconnect them from their now buried floodplains.  During storms, water that would have been absorbed by the floodplain is now displaced into areas of higher ground not historically inundated by a similar event.
Adjacent to the Manheim Farm Show grounds, the Chiques Creek Stream Restoration Project in Manheim Memorial Park has reconnected the waterway to its historic floodplain by removing a dam and the legacy sediments that accumulated behind it.
Legacy Sediments Removed
Chiques Creek in Manheim following removal of hundreds of truck loads of legacy sediments.  High water can again be absorbed by the wetlands and riparian forest of the floodplain surrounding this segment of stream.  There are no incised banks creating an unnatural channel or crumbling away to pollute downstream waters with nutrients and sediment.  Projects similar to this are critical to improving water quality in both the Susquehanna River and Chesapeake Bay.  Closer to home, they can help municipalities meet their stormwater management (MS4) requirements.
Bank-full Bench
Mark Metzler of Rettew Associates guides a tour of the Chiques Creek rehabilitation.  Here, cross vanes, stone structures that provide grade control along the stream’s course, were installed to gently steer the center of the channel away from existing structures.   Cross vanes manipulate the velocity of the creek’s flow across its breadth to dissipate potentially erosive energy and more precisely direct the deposition of gravel and sediment.

…and a highlight of the evening will be using an electrofishing apparatus to collect a sample of the fish now populating the rehabilitated segment of stream…

Electrofishing
Matt Kofroth, Lancaster County Conservation District Watershed Specialist, operates a backpack electrofishing apparatus while the netting crew prepares to capture the temporarily stunned specimens.  The catch is then brought to shore for identification and counting.

…so don’t miss it.  We can hardly wait to see you there!

The 2023 Watershed Expo is part of Lancaster Conservancy Water Week.

Photo of the Day

Legacy Sediment Removal and Floodplain Restoration
This stream restoration project is currently underway along a one-mile-long segment of Lancaster Conservancy lands along Conewago Creek.  The mountain of dirt is one of several stockpiles of legacy sediments removed to reestablish the floodplain’s historic geomorphology.  After eroding from cropland during the years prior to soil conservation, legacy sediments accumulated behind mill dams on waterways throughout the lower Susquehanna watershed.  After removal of the dams, creeks were left trapped within the sediment-choked bottomlands, incising steep muddy banks as they cut a new path through the former mill ponds.  Excavating legacy sediments from these sites eliminates creek banks and allows floodwaters to again spill directly into wetlands along the stream course.  With floodplain and wetland functions restored, nutrients are sequestered, high water is infiltrated to recharge aquifers, sediment loads from collapsing banks are eliminated, and much-needed habitat is created for native plants and animals.

To learn more about this project and others, you’ll want to check out the Landstudies website.