Native Fish Species Composition of Piedmont Tributary Creeks of the Chattahoochee River

The many present day creeks and small rivers that flow through the piedmont region of central Georgia originated between 15,000 years BP-8,000 years BP when water tables rose as a result of melting glaciers far to the north of the state.  Before this, during the Glacial Maximum, the regional landscape was much more arid and only the largest of rivers and creeks still flowed…and those were often low flowing and clogged with sandbars.  Intermittent springs probably occurred in the lowest areas of topography along the present day courses of smaller streams.  Climatic phases with increased precipitation raised the water table enough to cause water flow between springs, and these creeks eventually emptied into the nearest river.  So much atmospheric moisture was released at the end of the last Ice Age that rivers and creeks had a larger flow than they do today.  This occurred between ~10,000 years BP-~5,000 years BP when rivers were classified as “supermeandering.”  Fish found their way from rivers into newly formed creeks during the late Pleistocene/early Holocene, though a few species may had persisted in relic Ice Age springs before water tables rose.  About 40 years ago the noted naturalist, Charles Wharton, electro-fished a small unnamed creek located 1.4 miles south of Sopa Creek, a tributary of the Chattahoochee River, and he determined the “near original” composition of fish species typical of piedmont streams that flow into this river.  These creeks flow through steep terrain often between high bluffs and where protected are still very beautiful natural areas.

Cobb County, Georgia.  Charles Wharton electro-fished a small stream here over 40 years ago and determined the original fish species composition of piedmont Chattahoochee feeder creeks.

This is where Sopa Creek flows into the Chattahoochee River.  Sherman ordered his troops to cross over the rocks here during the Civil War.

The fish species Wharton found in his survey included band fin shiner ( Notropis zonistius ), central stoneroller ( Campostoma anomalum ), creek chubsucker ( Erimyzon oblongus ), Alabama hog sucker ( Hypentelium etowanum ), yellow bullhead catfish ( Ictalurus natalis ), bluegill ( Lepomis machrochorus ), and banded sculpin ( Collus carolinae ).  The band fin shiner is a small minnow native to the Chattahoochee River drainage, though it has been introduced to other river systems wherever fishermen dump their bait buckets.  The stoneroller is a widespread species in the Midwest.  It eats algae and may school in the hundreds.  They grow up to 8 inches long.  The creek chubsucker can grow twice as long as the stoneroller, and it eats small crustaceans and insect larva in addition to algae.

Alabama hog sucker.

The yellow bullhead catfish is omnivorous and can grow up to 6 pounds, though it normally reaches a weight of about 2 pounds.  Bluegills also grow large enough to make a good meal.  Early settlers placed fish traps in the nearest streams and caught supper, while they were busy clearing and cultivating their land.  Bluegills and catfish living in clear moving streams with rocky  bottoms probably taste better than those taken from muddy ponds.

Yellow bullhead catfish.

Bluegill sunfish or bream.

The banded sculpin is a freshwater relative of a large family of saltwater species.  Banded sculpins are nocturnal ambush predators that live under stones.  They compete with crayfish for the same type of habitat.

Banded sculpin.

The origin of the name Sopa Creek has a disputed origin.  This stream flows for 11.6 miles through Marietta until it empties into the Chattahoochee River.  Today, the headwaters emerge from a spring under a manmade culvert, but I’m sure the original landscape was picturesque.  Now, it is surrounded by suburban sprawl.  Some say this creek gets its name from the foam caused by water rushing through rocks.  The foam resembles soap spuds, and supposedly an early mapmaker misspelled soap.  Others claim the creek is named after an old Cherokee Indian (Old Sopa) who lived nearby.  He reportedly refused to be removed when is compatriots were force marched to Oklahoma on the Trail of Tears.

Reference:

Wharton, Charles

The Natural Environments of Georgia

Georgia Department of Natural Resources 1978

 

Tallulah Gorge

I visited Tallulah Gorge a few years before I started writing this blog, so at the time I didn’t think to write down my observations.  I can’t remember where I put the photos I took of that trip or if I even took any.  However, I found plenty of Tallulah Gorge photos online.  I do remember walking down a long flight of manmade stairs to the bottom of the gorge and on the way down coming face to face with a black vulture that was perched on a ledge.  I saw blueberry and blackberry growing on the canyon wall.  And I recall swimming in a very cold reservoir nearby.  Lately, I’ve been reading a new book, Roadside Geology of Georgia, by Pam Gore and William Witherspoon.  Their page on Tallulah Gorge reminded me of my trip there.  I didn’t realize Tallulah Gorge had such a fascinating geological history.

Location of Habersham County.  Tallulah Gorge is in this county.

The headwaters of the Tugaloo River eroded backwards upstream from the Tugaloo and captured the Tallulah and Chattooga Rivers both of which formerly flowed into the Chattahoochee River.

Tallulah Gorge is the 4th deepest gorge east of the Mississippi.

Tallulah Falls.  The sudden drop in elevation when the Tugaloo River eroded backward into the Gainesville Ridge created these falls.

The Gainesville Ridge separates the Chattahoochee River drainage from that of the Savannah River.  All streams on the west side of the ridge empty into the Chattahoochee River, while all streams on the east side of the ridge flow into the Savannah River or its tributaries.  Formerly, the Chattooga and Tallulah rivers were tributaries of the Chattahoochee River.  But the headwaters of the Tugaloo River eroded upstream into the Gainesville Ridge capturing the Tallulah and Chattooga Rivers.  These 2 rivers changed course making a sharp right angle turn through the Tugaloo River which empties into the Savannah River.  It’s a classic example of what geologists refer to as stream capture.  Geologists believe this stream capture event occurred “recently”, but I haven’t been able to find any studies of the exact age of the event, and  I think scientists have not determined the exact timing of this dramatic occurrence. Recently in geological time could be 10 million years.  Nevertheless, scientists believe the steepness of the gorge is evidence the stream capture occurred relatively recently.  Some of the cliffs are 600 feet high.  Geologists believe the gorge is geologically young because not enough time has passed for the high cliffs to erode away.  In older river and stream incisions, water eventually erodes the sides back, creating broad gently sloped valleys.  But at Tallulah Gorge, not enough time has passed for this to happen.

The rock along Tallulah Gorge is made of erosion resistant quartzite which is sandstone that has been metamorphized.  There is no Chattooga River gorge because the rock along that river is less resistant to erosion.  When the Tugaloo River eroded backwards and captured these 2 tributaries, the elevation suddenly lowered, creating the falls.  This change in elevation is the reason the Chattooga river is known for its white water rafting.

There are 2 types of environments in the vicinity of the Tallulah Gorge.  The cliffs provide nesting habitat for many species of birds (See https://markgelbart.wordpress.com/2013/05/19/piedmont-cliff-ecology/).  In pre-Columbian times bald and golden eagles and peregrine falcons likely nested here.  An acidic pine/oak woodland and forest grow on the rim of the gorge.  Plant species composition includes white pine, Virginia pine, table mountain pine, pitch pine, shortleaf pine, southern red oak, rock chestnut oak, scarlet oak, blackjack oak, red maple, sourwood, persimmon, mountain laurel, rhododendron, blueberry, and greenbrier.  This is the southernmost range limit of the Carolina hemlock.  Monkey-faced orchid and persistent trillium are rare plants that favor this moist, water-splashed environment.

The Soque River may be a remnant of the Chattooga and Tallulah Rivers before they were diverted from the Chattahoochee River Drainage to the Savannah River Drainage.  This is a beautiful small river with little public access.

Deep Creek and the Soque River are likely remnants of the Chattooga and Tallulah Rivers before they were diverted from the Chattahoochee River Drainage.  There are many species of mussels common to both the Chattahoochee and Savannah Rivers.  The Tugaloo stream capture event must explain how bivalves from the Chattahoochee Drainage colonized the Savannah.  For a while during this stream capture event, water must have flowed from the Savannah to the Chattahoochee as well because mussels originating from the former also made it to the latter.  However, it’s not clear how thie mussel exchange from the Savannah to the Chattahoochee occurred.