The Cahaba

For thousands of years, the Cahaba River, with the other rivers and
streams of Alabama, has moved unceasingly to the sea.And just beneath
the normally peaceful waters exist perhaps the greatest collection of
plant and animal life in North America.Overstatement?Hardly.

While Alabama is the 29th largest state, it ranks fourth in the number
of plant and animal species.Fully eight percent of all the freshwater
flowing through the continental United States flows through this state.
Only Florida can rival Alabama in the number of species per square mile.
Alabama's waterways host 38 percent of all the freshwater gill-breathing
snails, 52 percent of all turtle species and 60 percent of al the
freshwater mussel species. Since 1991, three new fish species previously
undescribed by science have been found in the Mobile River basin.

The Cahaba River has more fish species per mile, 131, than any river its
size in North America, including 18 species that exist only in the Mobile
River drainage area.To put this in perspective, the Cahaba has more native
species of fish than the entire state of California.The Cahaba River basin
supports 69 rare and imperiled species, including 10 fish and mussel species
listed under the U.S. Endangered Species Act.

In 1992, botanist Jim Allison discovered eight new species of plants in the
limestone bluffs of Bibb county overlooking the Cahaba that were previously
unknown to science.His discovery rivals the great expeditions to the heart
of Africa or up the Amazon river in the 19th Century.
 
Dr. Randall Haddock
"The best way to increase understanding of the river is the constant pursuit
of the truth, says Dr. Randy Haddock, field director and resident scientist
for the Cahaba River Society."I love to see people light up when I introduce
them to plants and animals they've never seen before and the tricks creatures
use to survive."

It also helps to be a nice guy."It says a lot about Randy that for several
years at our fund raising auction, a canoe trip with him has raised the most
money," says Beth Stewart, executive director of the Cahaba River Society. 

Better than the Discovery Channel

Some of the most exotic and unusual creatures live just minutes from your house.
They are perhaps swimming just beneath the free-flow surface of the Cahaba, or
buried in the river's rocky shoals. Many grow unnoticed on the limestone bluffs
towering above the current. The Cahaba is a paradise of diversity.
Perhaps the best known of the Cahaba's endangered inhabitants is the Cahaba Lily,
also known as the Shoals Lily. Once common on rivers throughout the South,, it
is now consigned primarily to a stretch on the Cahaba South of Booth's Ford near
the town of West Blocton. The Cahaba Lily is unusual in that it grows literally
in the middle of the river, wedging its bulbs between cracks in the rocks that
comprise the riverbed. Each spring, in May and June, the lillies rise above the
flowing current in an explosion of white and green.

Less captivating, but more unusual, are the Cahaba's mussel species. Burying
themselves into the rocky riverbed, the mussels are filter feeders, drawing in
water and filtering out the nutrients they need to survive. Historically, 42
species of mussels have been found in the Cahaba. Today, biologists count about
half that many. 

A mussel is able to inch about within a limited range, usually by extending a
foot, burying it in the rocks and pulling itself forward. Despite this limited
mobility, mussels have colonized the entire length of the Cahaba essentially by
fishing. Mussels enlist the help of various fish species to spread their larvae
using a variety of lures. 

Perhaps the most unusual is the Orangenacre Mucket. To disburse its larvae, the
Orangenacre extends a tube of mucus up to eight feet long with a perfect replica
of a minnow attached to the end. A bass, attracted by the movement, swallows the
bait, which explodes releasing the mussel's larvae. The larvae attach themselves
to the fish's gills and hitch a convenient ride upstream. The Orangenacre times
its fishing expeditions to the bass's spawning runs.

Each species of mussel has adapted its bait to catch specific kinds of fish; mussel
bait can resemble anything from minnows to worms to mayflies.

Such specialization comes with a price. If environmental changes affect the fish,
the mussels themselves become severely threatened. Randy Haddock, field director
for the Cahaba River Society, says we are losing species faster than we can
understand their ways. 

A Convergence of Time and Place

Two primary factors contribute to Alabama's, and specifically the Cahaba's, incredible
biological richness: habitat and time. Alabama stands at the convergence of five
geological provinces: Cumberland Plateau, Valley and Ridge, Piedmont and Gulf Coastal
Plain. Each physicgraphic region is marked by variations in structure and substance
and so creates unique habitats to which plant and animal species adapt. The Valley
and Ridge formation, through which the upper Cahaba flows, marks the end of the
Appalachian mountain chain. The upper Cahaba is marked by steeply sloping banks and
a riverbed of rocky shoals. it also has a temperamental nature, with great variations
in water height and speed. 

As the Cahaba flows out of the Valley and Ridge formation and into the Gulf Coastal
Plain, just below Centreville, it crosses the Fall Line, a demarcation of the sea's
ancient boundary. As the river crosses over, its character also changes. The final 80
miles of the river flow through flat, sandy terrain. It becomes wider, deeper and less
hurried. 

The great changes in topography and the river's natural riffle-pool-riffle-pool tendency
create great variations in habitat, to which species have adapted.

Another factor in the development of so many variations in life is time.

Ten thousand years ago, during the Pleistocene Glaciation or Great Ice Age, glaciers
pushed south as far as Kentucky and Northern Tennessee. While Alabama probably
experienced cooler summers and more severe winters than we have today, it was spared
the scouring that Northern habitats endured.

Likewise, as Alabama's last freeflowing river, the Cahaba flows undammed for almost 200
miles. This freedom keeps intact the great variety of habitats endemic to a freeflowing
river. By contrast, with the damming of the Coosa River and the drowning of the Coosa
shoals, came the extinction of 27 species of aquatic snails. It is considered by many
natural historians the single greatest extinction catastrophe in American history.

The Cahaba River is a relatively small, unpretentious river. It flows practically unseen
through the heart of the Birmingham area. And yet, beneath its silent waters and along
its angled banks, it is teeming with life in unimagined variations.

"I love to see people light up when I show them some new, or unusual animal that is living
literally in their back yard, and the tricks they use to survive," says Randy Haddock.
"It one of the best parts of this job."
 
Jennifer Fairly
For Jennifer Fairley, environmental activism is about asking questions. This spring, Fairly
began asking questions of the United States Postal Service and their plans to build a new
facility on top of Patton Creek, a tributary to the Cahaba running through Vestavia Hills.

Jennifer's questions ultimately led the Postal Service to order an environmental assessment
of the site, which will be made public this month. "The assessment is important," says Fairly.
"Prior to my asking questions, I don't think the Post Office understood that this was an
environmentally sensitive area. Now they seem to want to do everything to make sure no damage
is done."
 
Swimming Hole or Sewer?
For thousands of years people have lived along the banks of the Cahaba River, relying on it to
provide the necessities of life. People have assigned many values to the Cahaba, some strictly
utilitarian, others more abstract. Today, in a great twist of irony, the Cahaba is both our
most important drinking water supply and our central sewer.

The Cahaba is the primary source of drinking water for one-quarter of Alabama's population.
The Cahaba "peopleshed" includes more than 800,000 people in the Birmingham metropolitan
area. In 1911, the Birmingham Water Works Board impounded the Little Cahaba to form Lake
Purdy and solidify the city's drinking water supply. It raised the dam again in 1929.
Ironically, most of Birmingham's drinking water, outside of drought periods, is not
released from Lake Purdy but taken directly from the main stem of the Cahaba. Each day
the city takes from 50 to 100 million gallons of water from the Cahaba River/Little
Cahaba/Lake Purdy system, averaging about 57 million gallons per day.

Our other primarily utilitarian use of the Cahaba is to dispose of waste. Each day
Birmingham returns approximately 16 million gallons of water to the river as treated
or partially treated sewage. In all, 40 million gallons a day of treated sewage is
released into the Cahaba along its length. In addition, the Alabama Department of
Environmental Management has licensed 103 industries to discharge waste at 167 points
along the river. 

Perhaps the most under-appreciated value of the Cahaba is its simple, natural beauty.
No other city of Birmingham's size contains an urban environmental experience to rival
the Cahaba. One unfortunate characteristic of the river is that it's practically
invisible, particularly in the Birmingham area. To see the river, and certainly to
understand its unique nature, one must literally step down to the water's edge. The
Cahaba is best appreciated from the seated position. To quote the late John Henley,
one of Birmingham's leading businessmen and environmentalists (though he would have
shaken his head at the word): "The Cahaba is the study the concepts of watersheds,
perfect sized river, too big to wade, biodiversity, and natural cycles. To too small to
boat, perfect for a date more than 1,500 students and canoe."

As the river winds its way beneath the steep rocky slopes it passes through forests of
incredible diversity, Along the banks willow, ash, boxelder, sycamore, oak, poplar,
hickory, birch, pine and maple trees cast long, knotted limbs across the river in a
canopy of vibrant green. Wildflowers explode along the banks each spring, adding
brilliant patches of color to the green-draped landscape.

In addition to canoeing, people have traditionally used the river for a variety of other
outdoor activities. The stretch of the Cahaba between Harrisburg in Perry County to U.S.
80 in Dallas County is perhaps the most actively used section of the river. Canoe launch
sites afford access to the river to anyone willing to haul their canoe a short stretch.
Here fishermen routinely catch spotted bass, redeye bass, largemouth bass, catfish and
bluegill bream. 

The Cahaba River Society, to introduce people to the river's charms' organizes canoe
trips on the river, frequently camping overnight.

"The river is full of beaches and sand bars," says Haddock. "The beaches are always
covered in animal tracks from deer to armadillos. You can see more types of birds than
you can imagine. We routinely see bald eagles now."

The Cahaba also presents a unique educational opportunity. As one of the few undammed
Southern rivers, the Cahaba is one of the last places for biologists to study these
hotspots of biological diversity.

Two years ago, the Cahaba River Society received a grant from the Chesapeake Bay
Foundation to begin an educational program called CLEAN. The grant, one of only three
nationwide, allows the Cahaba River Society to conduct student field trips, teacher
workshops and restoration projects. Students learn through hands-on experience using
cast nets, seines and water testing kits. They 425 teachers have participated in the
CLEAN program from a mix of suburban and inner city schools.

"To really appreciate the river," says Beth Stewart, executive director of the Cahaba
River Society, "you have to get wet, put your hands in the water. Once you come in
contact with the river, it is hard to ignore anymore."

A Constant Threat 

The Cahaba faces several serious threats, which endanger the health of the river. There
are two sources of pollution-point source and nonpoint source. Point source pollution
typically comes from the end of a pipe. This includes sewage and industrial discharge.
While still a serious danger to the river, point source pollution is at least recognized,
and corrective measures have been implemented in many cases.

Non-point source pollution includes stormwater runoff from parking lots and neighborhood
storm drains. With this runoff comes a variety of toxic substances from creosote on
telephone poles to heavy metals from the break pads of cars. It includes sediment from
construction sites to fertilizer and pesticides applied to lawns. Correcting nonpoint
source pollution is a far more complicated task.

From these two sources come several different types of pollution. Sediment from development
is nothing more than dirt, sand, or rocks. As it enters the river, however, it slowly
settles on the bottom filling in the rocky shoals that are habitats for the insect life
at the bottom of the food chain. Sediment also damages fish breeding sites and destroys
the habitat of the Cahaba Lily by, again, filling in the cracks in the rocky riverbed
where the bulbs root.

It has an economic impact as well. Extreme levels of sediment clog and damage the equipment
that processes our drinking water, making it more expensive to produce.

Nutrients are another serious source of pollution. Fertilizer, mostly from stormwater
runoff and raw or partially treated sewage cause algae to bloom in the water. These giant
blooms create severe fluctuations in the oxygen levels of the river, stressing the
inhabitants. The Birmingham Water Works have frequently chosen to shut off their intake
equipment when large blooms occur, rather than process the algae-infested water.

Toxins are an obvious pollutant. Most come directly to the river carried by stormwater
running through our drainage system. Toxins can have a devastating effect on river life,
as demonstrated by the Dursban spill into Village Creek.

Our encroachment of the river also poses serious problems. The forests that buffer the
river act as filters, reducing runoff and filtering many of the toxins that otherwise
would go directly into the river. As development encroaches, that buffer is reduced or
eliminated.

Biologists recognize two groups to describe the way species adapt to their habitats:
specialists and generalists. Generalists, which include many types of fish, are adaptable
to a variety of circumstances and habitats. if conditions become unfavorable they simply
adapt or move. Specialists, on the other hand, exploit a particular niche in a habitat-such
as mussels that rely on a particular type of fish to help carry their offspring upstream.
Specialists enjoy advantages when environmental conditions are relatively stable. If
conditions change or become unfavorable, even slightly, specialists cannot adapt and are
often lost. The danger is that constant shocks to the river system will leave only the
generalists species and eliminate many of the most interesting plants and animals. To
quote Loren Eisley, poet and scientist, "The perfectly adapted perish with their
environment."

What will it take to ensure the river's protection? A great deal, actually.

A unified watershed management plan to create intelligent, consistent rules for development
for the entire upper Cahaba would be a high priority, but difficult to achieve. Stricter
enforcement of existing laws and regulations by ADEM and the EPA are positive steps forward.
But perhaps the most important step is the education of individuals. Most people don't think
of themselves as polluters, but every basketball that rolls down the street or fertilizer
dumped down the drain ends up eventually in the river.

The Cahaba River is our natural treasure. It is our heritage. The Cahaba has sustained
civilizations for as long as people have inhabited this region. Today it is threatened
on all sides. But a renewed awareness of our dependence on the river has sparked new calls
for action, While no one has signed a truce between the opposing views of development and
preservation, there is at least an increased sense of optimism.