Although you don't really need to learn macroinvertebrates down to the family level to use the SOS method of stream monitoring, after monitoring the same stream for a while, you'll notice individuals within the broad identification groupings.  Usually, the Clinch River is chock full of Common Stoneflies (Family Perlidae), which have a beautifully mottled thorax like the one shown to the right.  But this week we stumbled across a new family --- Pteronarcyidae, or the Giant Stoneflies (pictured above.)

I was thrilled to read that the presence of Giant Stoneflies in the Clinch is a sign of good water quality since they are even more sensitive to environmental stresses than are other stonefly larvae.  Unlike the mighty hunters in the Common Stonefly family (which eat just about any smaller insect they can get their hands on), Giant Stoneflies shred and scrape debris for their dinner.  And, as you can see, they are so slow-moving that they grow algae on their backs.

Giant Stoneflies turn into salmonflies, thus named because of their importance in feeding fish.  Fly fishermen often try to mimic salmonflies when they create stunning lures like the one shown here.  I guess stream monitors aren't the only ones interested in identifying aquatic macroinvertebrates down to the family level.

Stream monitoring through the Save our Streams network is a great way to get involved in the health of your local waterways.  The system uses an ingenious series of biological indicators so that your average Joe can quickly learn to assess the water quality in a stream.  Rather than measuring the levels of every possible contaminant, you just scoop a random sample of aquatic macroinvertebrates (water bugs) out of the stream, pluck them off the net into white ice cube trays, and then tally up how many of each type of bug is present.  Do a bit of simple math and you can rate your stream on a scale of 0 to 12, where 0 to 7 ia unacceptable water quality conditions, 8 is a gray zone, and 9 to 12 means the stream is healthy.

In the mountains of Virginia, good quality streams tend to be chock full of scary-looking stoneflies (top photo) and delicate mayflies, while lower quality streams host worms, midges, and lunged snails.  Although the Save our Streams method doesn't delve further than high and low quality water, a book like J. Reese Voshell, Jr.'s A Guide to Common Freshwater Invertebrates of North America will turn your haul into even more of an indicator of water conditions.  For example, snails are usually abundant in hard water where dissolved calcium makes it easy to build their shells, and common netspinners (like the ones pictured below) abound in rivers with high levels of suspended debris for them to catch in their nets.  Straight pipes in the watershed upstream from our testing site make common netspinners especially abundant in our portion of the Clinch --- perhaps the reason our most recent sampling sunk the Clinch down in the unacceptable zone.

Although a few of the aquatic macroinvertebrates we net during stream monitoring live in the river all their lives, many more are larval stages of flying insects.  Most of the "stream bugs" live by scraping algae off rocks, filtering or capturing debris out of the water, or eating smaller macroinvertebrates.  None of them bite.

The Izaak Walton League of America developed the Save Our Streams network, but most states seem to have their own organization that coordinates with volunteers to sample local streams.  Here in Virginia, Virginia Save Our Streams runs training weekends and compiles data on their website.  Even more local groups, like The Clinch Coalition, often have stream monitoring equipment available for you to borrow and will help set up teams of two or three to monitor each stream.  If you decide to join up, you'll be responsible for monitoring your stream four times a year, a fun excuse to jump in the water.

April Cain, a St. Paul native now living in Richmond, emailed me some fascinating information to supplement my tale of Oxbow Lake's construction.  She wrote:

Nearest towns: Lebanon, Cleveland

The Pinnacle is worth visiting just for the scenic swinging bridge, the raging waterfall, and the craggy rock feature after which the area was named.  But you will also want to spend some time hunting down the preserve's rare and unusual species.  Steep limestone cliffs provide habitat for Canby's Mountain-­Lover, Carolina Saxifrage, Northern White­-Cedar, and American Harebell, while Glade Spurge is found along the
side of Big Cedar Creek.  Unusually deep purple hepatica flowers pop up along the trails in early spring, along with a host of the usual early spring ephemerals.  The Pinnacle also abuts the Clinch River, giving you another chance to explore the river's diversity.

A river naturally winds through the landscape, changing its course over time to follow the path of least resistance.  In the mountains, river routes are usually tightly constrained by steep hillsides, but in flatter parts of the country a river turns into a sinuous snake.  These looping curves, known as meanders, are a natural result of erosion and deposition.

Erosion lengthens even the smallest curve as water rubs up against the outside bank.  If you imagine cars passing each other on a curving racetrack, you will realize that the car (or water) on the outside of the curve must travel much faster than the one on the inside of the curve to reach the straightaway at the same time.  Just as the faster race car would cause more damage if it ran into the wall of the track, quickly moving water has a greater ability to cause erosion.  The water on the outside of the curve carries away soil and gravel that was once part of the curve's outside bank.

Meanwhile, the water on the inside of the curve dawdles, taking its time to reach the straightaway.  As water slows down, it can no longer hold as much silt and gravel, so the slow-moving water drops dirt and debris out of its grip.  A sandbar forms on the inside of the curve, then trees colonize the area and new land is formed.  The combined actions of the eroding water on the outside of the curve and the depositing water on the inside of the curve results in a river bend that may be a mile or more long.  Over time, a river that was once nearly straight turns into a winding snake.

The next step in an oxbow lake's construction often comes during a flood.  Raging waters back up as they push their way around a curve, and suddenly the water is high enough to bypass the curve and make an overland shortcut to rejoin the river further downstream.  Once water has flowed across the shortcut, it becomes the path of least resistance --- why would any water take the long route through the sinuous curve when it could just barrel on through the shortcut and be downstream that much faster?

The old curve of the river is now a lake of still or slowly moving water.  The so-called oxbow lakes are named from their resemblance to the U-shaped yoke once put around an ox's neck to harness it to a plow or wagon.  Although oxen are seldom harnessed in today's society, oxbow lakes remain a common feature in our landscape.

Despite sharing its name with these natural oxbow lakes, St. Paul's lake is a special case.  Oxbow Lake wasn't created by flooding, though its creation was spurred by a massive flood in the early 1980s.  After receiving extensive flood damage, the town of St. Paul chose to re-route the Clinch River to bypass their buildings, giving the town a bit of protection from later floods and forming a man-made oxbow lake from the discarded portion of the river.

Although the floodplain is brimming with life, the Clinch River's true claim to fame lies beneath the surface.  I dig my hands into the sand along the river bottom, and before long my fingers touch something hard.  The flowing water washes away dirt and reveals an elongated seashell --- one of the Clinch's many freshwater mussels.

The Clinch is home to 45 species of these mollusks, with names ranging from the evocative Little-winged Pearlymussel to the less enticing Tennessee Heelsplitter.  Although they all look pretty much the same to the untrained eye, their astonishing diversity is one of the Clinch's main claims to fame.  For a bit of perspective, you'd have to explore every stream in Europe and temperate Asia to find as many species!

Adult mussels are sedentary, moving no more than a few inches along the bottoms of the rivers and spending their time flushing water through their bodies and extracting microscopic organisms to eat.  Their young, however, are more adventurous.  Mother mussels trick fish into coming close by showing off fleshy appendages that act as bait.  When a fish swoops close to eat the "bait", the mussel shoos her babies out into the water and they dash to latch onto the fish's gills where they'll spend the rest of their early childhood.

Like the picky caterpillars of the Pipevine Swallowtail, each species of mussel has a different species of host fish which it uses as its nursery.  Perhaps a decline in their host fish is partially responsible for the recent loss of mussels from the Clinch River --- whatever the reason, over the last few decades, species after species has dropped out of sight.  In the 1960s, 53 mussel species were found in the Clinch, but more recent surveys have only been able to turn up 37.

An even more likely reason for the plummeting diversity of the Clinch River is dirty water.  Both mussels and the fish they depend on require pristine water to survive, and the Clinch River can no longer be considered pristine.  The Carbo coal-fired power plant a few miles upstream from St. Paul has severely damaged the Clinch River through two toxic spills, one of alkaline fly ash slurry in 1967 and one of sulfuric acid in 1970.  The combination of these two spills affected the Clinch River for nearly 90 miles, all the way downstream  to Tennessee, and created a 12 mile dead zone in which nearly all mussel species were killed.

In 2009, Dominion Virgina Power began construction of a second coal-fired power plant on the banks of the Clinch, putting the future of the remaining mussels in jeopardy.  Although appeals to the Virginia State Corporation Commission, Department of Environmental Quality, and various legislators have been ignored, a groundswell of opposition has sprung up around the region.  Please take a few minutes to write to your congressmen and ask that the Clinch's unique beauty be protected for future generations to enjoy.

Heavy rains saturated the soil, but the rain kept falling.  Before long, creeks were up, pouring muddy water into the Clinch.  Slowly, the river raised its ponderous bulk up above the banks, spreading out across the flat land on either side, lapping at the feet of the nearby hills.  The aptly named floodplain was underwater.

As the rains ended, the river shrank back down between its banks.  But the slowly moving water that had spread across the floodplain left behind rich mud and sand, carried off slopes above by the eroding forces of water and now enriching the bottomland on either side of the Clinch.  Seeds had also been carried by the rushing water --- not just Bladdernut pods, but also the seeds of Sycamores, Black Willows, and Box-elders.  Some trees on the Clinch’s bank had been knocked over by the raging river, leaving gaps in the canopy and sunny spots on the forest floor.  The forces of nature that shape the floodplain forest had done their work.

The entire length of the River Trail runs through floodplain forest where signs of past floods abound.  The trail follows the curve of the Clinch River, wending between Sycamore, Box-Elder, and Slippery Elm --- typical floodplain trees that can colonize areas disturbed by high water and grow quickly to gain a foothold before the next flood comes to wipe slower-growing trees away.  The floodplain forest tends to be more open than the denser forests on higher ground, and plenty of light filters down to feed the healthy shrub layer dominated by Black Willow, Common Elderberry, Paw-paw, Spicebush, and Bladdernut.

Beneath the shrubs, the forest floor is coated with herbs that thrive on the infrequent deposits of rich soil.  Virginia Bluebells form masses of brilliant blooms in the spring, giving way to Purple-node Joe Pye Weed and Wingstem in the summer.  During every season, the floodplain community is vibrant with life.

The same rich soil that feeds the floodplain forest has drawn farmers to riverbanks for millions of years.  The earliest human civilizations were located in fertile river valleys, like the Tigris-Euphrates, Nile, and Indus River civilizations that arose about five thousand years ago.  Even in our region, many of our towns (like St.  Paul) are located on the banks of rivers that provide us with water and rich soil for farming.  The unfortunate side effect of our interest in riverbanks is the demise of the floodplain forest --- while a few patches of old growth oak-hickory or cove hardwood forest may be found scattered across our region, floodplain forests are typically young and overrun with invasive species.  In many cases, the forests have been completely replaced by pastures or farmland.  In other areas, rivers have been dammed so that they no longer flood above their banks, protecting houses on the rivers’ edges but breaking down the complex web of forces that feeds the floodplain forest.

Although the Clinch River is dammed in Tennessee, the Virginia section of the Clinch flows as a natural river.  With new government programs that help farmers create riparian buffers --- strips of trees on either side of rivers fenced out of the adjacent pastures or cropland --- the floodplain forest seems to be rebounding.  As you walk the River Trail, you can see firsthand the resiliency of the floodplain forest.  Even though corroded barbed wire hints that the land was pasture in the not too distant past, the beautiful white trunks of Sycamores arch over the water and spring ephemerals dot the forest floor.  When it rains, I anticipate the rise of the life-giving river, feeding Sugar Hill’s floodplain forest.

As travelers pass by the small town of St. Paul, Virginia, on alternative route 58, they may notice a little blue and white sign announcing “hiking/biking.” I drove by this sign at least a hundred times before I bothered to stop, assuming that the wayside was a small town park with a playground and paved walking path. Imagine my surprise when I was finally introduced to eight miles of trails threaded through a hundred acres of woodlands and meadows.

Sugar Hill contains the only public hiking trails along the Clinch River in Virginia. The river itself must be seen to be believed, with its rare aquatic life including the two-foot long Hellbender salamander and 21 types of federally threatened or endangered mussels and fish. The Nature Conservancy calls the Clinch the number one river worth protecting in entire the continental United States, and I would add that it is certainly the number one river worth visiting.

But Sugar Hill is more than just a river trail --- it is a microcosm of central Appalachian ecology. Spend a day or two on its trails and you will walk through floodplains, cove hardwoods, and oak-hickory forests, through open fields, young woods, and climax forest. Here, you can listen to the spring chorus of mating frogs and toads, uncover the secrets of the smelly millipede, and trace the history of a sex-changing flower. Sugar Hill even offers a human mystery for the amateur historian, a real-life whodunit which has yet to be solved. All told, the preserve is the perfect spot for naturalists to hone their skills of identification and deduction.