Federation Blog

Spurred on by the comments of a colleague, "you've got to see the water clarity on Flat Creek where the beavers are.  It's crystal clear."   I couldn't keep myself away.  I took the rare opportunity, with the leaves down and the marsh frozen enough to support the weight of an adult, to hike down Flat Creek, through the inundated/frozen marsh towards tidewater.   Not far down from Governor Bridge Road, I came across the first of several beaver dams, clearly very actively maintained.

Further down the system, there is still submerged aquatic vegetation (SAV) ( I think it may be one of the Sparganium species) alive.  I even caught glimpse of a small, black fish.  The water clarity in the system is incredible.  Below, you can see straight through to the bottom of about 3 feet of water (the novelty of that sounds more depressing than it should).

A little further down, a well-buttressed dam holds back what must be several acre-feet of water and emergent wetland.  Really something to behold.

Several hundred feet down from the road crossing, the marsh opened up as I approached tidewater.  The white house in the photo below is actually on the other side of the South River.

 

 

Today I was out with USFWS performing the fall monitoring for our famous South River Cancerous Catfish.  The site was in the section near the ski zone in the northern part of South River.  With every catch the majority of the catfish had tumors, either on the face or back.  This is completely and utterly depressing to know that our river has no industry, but industry like water.  To know that where we have cancerous catfish, people are swimming, skiing, and fishing in waters with known problems.  Not only did the fish have horrible tumors, but they were anorexic.  Tomorrow I will be in the lab with USFWS helping to necropsy the catfish to help find the source.  But in the meantime --- Our river has a large problem.

-----Diana

Ever since having found the old mill dams on Flat Creek last winter, and the massive amounts of sediment behind them (see below), one question continued to nag at me: Just how much silt is still trapped up in that stream valley? 

You see, recent research coming out of Franklin & Marshall College, and backed up by quite a bit of ground truthing throughout the region suggests that what we now think of as streams bear almost no resemblance to what those systems looked like just 300 or 400 years ago.  This is not to state the obvious, that the land uses around many of these systems have changed dramatically since the pre-colonial days, but instead to challenge the entire notion of what a "stream" is.  Radiocarbon dating of soil strata at sites throughout the mid-Atlantic has consistently shown a similar pattern: several inches of quartz pebbles and gravel, overlain with a several inch layer of peat (often containing still viable seeds), covered with between 1 to 3 meters (3-10 feet) of legacy agricultural sediments, washed into stream valley over the  past several hundred years (see below; Figure from Walter, R., & Merritts, D. (2008). Natural streams and the legacy of water-powered mills. Science, vol. 319).

The quartz bedding and peat layer extend stream valley wide, but the stream "channel" occupies only a fraction of that width, cut down through the legacy sediments, and often down through the peat layer and/or the quartz gravel. When that occurs, the peat, which is indicative of a historic wetland complex,  shows up as a black or dark gray band of soil (see below).

At Flat Creek, the eroding stream still hasn't hit that peat/gravel band, so the question remained: how much lower than the existing stream bottom was it?  There was only one way to find out.  Armed with soil auger in hand, I cored through the stream bottom (see below).

After piercing about 5' of unconsolidated silt and mud, I hit the "bottom", a mix of sand, quartz pebbles, and woody stems and bark (see below).

Which means that the historic stream and wetland complex that once occupied this segment of Flat Creek is now buried under between 15 and 20 feet of fine agricultural sediments, slowly washing their way down towards tidewater.  Though, thankfully, we have two beaver complexes between this area and tidewater right now.

Over the past couple of months, both Diana and I had noticed that the culverts under Governor Bridge Road, where it crosses Flat Creek, were suspiciously filled with water. 

 We had both tried to get into the forest/swamp interior to determine the source but had been turned away by thick foliage and a high water table.   

This morning, however, with the gracious support of John Koontz and his wife (thanks for the limeade, Frances!), John and I paddled into Flat Creek from tidewater.  First, we tried the wide, eastern branch, which simply ended in a stand of cattails and arrow arum. 

Not to be dissuaded, we went up into the narrow central channel through the marsh until we encountered the scene below:

There was a slight "bump" in the landscape that was now home to a thick stand of phragmites, but just beyond laid open water.  For John, in his handsome, handmade rowboat, this was the end of the line, but he kindly agreed to stick around while I hopped onto the hummock and lifted the kayak through the gap. 

Almost as soon as I started paddling into the open water I was greeted by the curious beaver (middle of the picture).  

His/her handiwork was all over the place in the form of a stash of gnawed branches and additional dams, all up through the system. By the time I had reached my limit (should have brought the muck boots), I had encountered three levels of dams, each spaced a couple of hundred feet apart and each only a few inches high.

With the mystery solved, here's hoping the beaver will be allowed to remain, slowly helping to improve the water quality of the South River.

The Magothy has Dobbins and Little Dobbins, the Severn has St. Helena's, and the Rhode has Big and Flat Islands.    The South has very few true islands of note and most of those called out as "islands" (e.g., Turkey Point Island, Little Island, and Smith's Island) are connected to the mainland via causeways, ala Gibson "Island".   Until relatively recently though, there was a true island located north of the Riva bridge called "Goose Island." Below, it is called out on a 1993 USGS map of the river, near the mouth of Flat Creek, just off the shore of Glen Isle (perhaps it was the inspiration for the name of the community).  

Presumably, as a result of wave action, subsidence, and sea level rise,  Goose Island was lost to the tides at some point in the past couple of decades.   Oddly enough, though now beneath the briny depths, its phantom is still called out on the google earth aerial maps, with its silhouette clearly visible.

 To this day a shoal - a shallow, sand bar - still remains where the island once stood, a popular place for party goers and water lovers to gather on a hot, summer day.

 

Near St. George Barber Marsh in the South River on July 9, 2009 at 0830 am I came across a large algae bloom and scoped up about 30 dead catfish.

Since 4th of July the South River has had numerous "small" fish kills.  Mostly catfish and menhaden.  My question to our government is what constitutes a "real" fish kill- unless hundreds of thousands of menhaden die, then it seems that no one turns their head.  Sad.--Diana

Most of us are familiar with the almost ubiquitous Great Blue Herons.  Their size and their distinctive squawks are hard to miss as they fish in the creek or fly overhead. A lesser known cousin, the Green Heron (Butorides virescens), is a beautiful specimen in its own right.   The photo below was recently taken by member John Koontz as he was out paddling around Flat Creek.  

A picture taken from the marsh at the top of Flat Creek, looking towards the South River, is below. 

This weekend, we received reports from two different sources, one on Flat Creek and one on Church Creek, of hundreds of dead fish.  The species found included menhaden (shown below), catfish, rockfish, and croakers. 

Chances are, the fish died as a result of the very low dissolved oxygen (DO) in the river.  Diana has been finding extrememly low DO since early June, which is the result of nutrient-charged algae blooms decomposing and the aerobic bacteria consuming them pulling all of the oxygen from the water column.  Please report any fish kills that you come across on the river, and pictures are always appreciated.  

 Below are several of the croakers and catfish found dead on Church Creek. Necropsies performed by Diana indicate that they died as a result of suffocation.

It's been a busy week.  Lot's to blog about some other time.  For now though, here's another great osprey shot from member John Koontz.

 

 Photo courtesy John Koontz