Investigate Alabama’s WaterwaysAlabama is one of the top ranked states for freshwater habitats and resources. Alabama has more navigable stream miles than any other state and is ranked 7th in the country for its amount of stream miles. Freshwater habitats including rivers, streams, lakes, marshes, bogs, and estuaries provide the state with unique habitats. Alabama’s unique geological features and abundant freshwater ecosystems allow for a high level of biodiversity (the variety of living things in an area) in the state.
Black Warrior River
Dreamstime
A watershed, also called a drainage basin, is an area of land through which rainwater drains by flowing across, through, or under the soil surface to a common low point (definition from ACES). Every body of water has a watershed. It may drain into a larger stream, lake, wetland, estuary, or ocean. A watershed includes the land, air, water, and living things in that location.
Different watersheds are separated by locations that are higher in elevation, called ridges. Smaller watersheds separated by lower ridges can be contained within larger, major watersheds.
At the highest point, water begins to flow downhill, eventually collecting in streams. These initial (1st order) streams will join additional streams, and these larger streams will eventually connect with major rivers or lakes.
Ground water, water found in spaces between soil particles underground, also moves downwards towards the nearest outlet such as a stream or spring (a place where ground water meets and emerges from the land).
“We all live and work in a watershed, as all land is part of a watershed. Your everyday actions (work, play, and general living) can impact (positively or negatively) the quality of water that flows from your watershed. As water flows through the system, the impacts are cumulative. This means that everything you do on the land can impact the water that flows to your downstream neighbors. Likewise, everything that landowners above you do impacts the quality and quantity of what flows across your land.” (Quote from ACES)
Diagram of a Watershed
Dreamstime
Additional habitats and functional water sources within watersheds include:
Diagram of Water Cycle
(showing aquifer and groundwater)
Dreamstime
Alabama has several smaller watersheds within three broad areas: the Tennessee River drainage in the northern part of the state, the Mobile River Basin in the central part of the state, and the Coastal Drainages in the southern part of the state.
The Tennessee River drains about 13% of Alabama’s land area. This drainage area contains the Tennessee River as well as Pickwick Lake, Wilson Lake, Wheeler Lake, and Lake Guntersville.
The Mobile River Basin drains about 63% of Alabama’s land area. It contains the upper Tombigbee River, Black Warrior River, lower Tombigbee River, Cahaba River, Coosa River, and Tallapoosa River. Lake Martin, Weiss Lake, and Smith Lake are located in this drainage area.
The Coastal Drainage area in south Alabama contains smaller river basins that empty into the Gulf of Mexico.
Alabama Watershed Map
Auburn University Water Resources Center
River Formation:
When precipitation falls, water runoff flows downhill and begins collecting in channels called streams. The initial channels that form are called headwater streams or 1st order streams. When two 1st order streams join, a 2nd order stream is formed. When a 2nd order stream meets another stream, a 3rd order stream is formed.
A river is a larger stream of water that flows through a channel towards the sea. Smaller streams that flow into major rivers are called tributaries.
Stream Order Diagram
Wikimedia – Langlaufer
Stream Habitats:
Different parts of streams and rivers provide different habitats for aquatic wildlife. The headwaters of a stream are often very different from where a river meets the ocean or a lake. Headwaters often flow quickly through shallow channels in the steep terrain. Farther downstream, the gradient is less steep, and waters tend to flow more slowly in deeper channels.
Sections within a single stream are often different from one another. Areas where streams are more shallow and tend to flow faster, often over rocks, are called riffles. An area of a stream that flows smoothly is called a run, and deep areas where water moves slowly and deposits fine sediment are called pools. Different aquatic organisms are specifically adapted for these different microhabitats (smaller unique habitat within a larger habitat or ecosystem).
The stream bottom provides habitat for benthic organisms (organisms that live on or under the ground layer beneath a stream). Some streams have a rocky surface underneath, some have sandy bottoms, and some have areas with fine particles. Each of these materials provides a different type of habitat suitable for different aquatic organisms.
A riparian zone is an area directly next to a stream including the floodplain (where water can overflow). Many living things are specifically adapted to live in these types of areas.
Parts of a Stream
Missouri Department of Conservation, Texas Parks and Wildlife Department, The Meadows Center for Water and the Environment – Rudolph Rosen
Floodplain Diagram
flickr – placeuvm
Alabama Rivers:
The diverse geology of Alabama leads to a variety of rivers and streams that are noticeably different depending on the location in the state.
The rivers and streams in the northern part of the state tend to have faster flowing areas over metamorphic rock that is not easily weathered. These rocky bottomed streams are characterized by having clear water with shallow areas of elevation change providing a rapid effect.
As some of these streams connect further south in the state, the channels begin to widen while the slope of the land begins to decrease. Streams in the southeastern plain ecoregion are often more wide and slow moving with sandy bottoms.
In the coastal plain ecoregion, rivers move slowly through wetland or swamp areas surrounded by forests. As vegetation decays in and around the slow moving water, tannins are released, staining the water, giving them a dark appearance. These blackwater streams and rivers are characteristic of the southern part of the state. The areas where these large freshwater rivers meet the saltwater from the sea are called estuaries. Coastal Alabama is also home to many salt marshes (areas of coastal grasslands that are frequently covered by the tide.
Cheaha Creek, Cheaha Creek Gorge, Clay Co. AL
photograph by Alan Cressler
Perdido River, Perdido Watershed in the Southeastern Plains Ecoregion
flickr – FWC Fish and Wildlife Research Institute
Many of Alabama’s rivers and streams are known for their high diversity of freshwater fishes and snails.
Major Rivers in Alabama
Wikimedia – pfly and John Lambert
Lakes and ponds are characterized by having standing water (water that is not flowing).
Ponds are smaller and more shallow than lakes and keep a constant temperature throughout the pond. Because ponds are relatively shallow, sunlight is able to reach the bottom of the pond, allowing plants to grow throughout the pond. These aquatic plants play an important role as the producers of the aquatic food chain.
Lakes are larger and deeper, giving them a range of temperatures depending on the depth of the lake. Shallow areas near the edge of a lake is called the littoral zone and are similar to ponds in their biology. Further from the edge of a lake where the water is deeper is called the limnetic zone. The upper part where sunlight can reach is called the phoic zone while the deeper part where sunlight cannot reach is called the aphotic zone.
The bottom (benthic) zone of lakes collects small particles of decaying material. Certain organisms are specifically adapted to live in this benthic environment.
Pond Ecosystem
Dreamstime
Zonation in Lakes and Ponds
Dreamstime
Alabama Lakes:
All lakes in Alabama were created through the process of dam construction for purposes like electricity generation, flood control, drinking water, agricultural supplies, and navigation.
Lake Guntersville is the largest lake in Alabama and was constructed to allow transportation through the Tennessee River in the area and to help control floods.
Lake Guntersville – Guntersville, AL
flickr – Juliette Rien
The variety of living things in an area is called biodiversity.
Because Alabama has a wide variety of terrestrial (land) habitats and several major rivers running through the state, there is a wide range of habitats for organisms. This gives Alabama more biodiversity than almost all of the other states in the United States.
Alabama is ranked 4th place for most biodiversity in the United States and has more biodiversity than any other state east of the Mississippi River! It’s widely agreed upon that Alabama is ranked 1st place for freshwater biodiversity, specifically for several major freshwater animal groups, including those listed below.
Fish Diversity
BiodiversityMapping.org – Clinton N. Jenkins (Florida International University, Saving Nature)
While Alabama is ranked 4th place for biodiversity, it is ranked 2nd place for extinction. The numerous waterways and unique ecoregions that make Alabama so spectacular are the same reasons that make the biodiversity in Alabama so vulnerable. The major threats include:
Pratt Cotton Gin and Dam located in Prattville, Alabama on the banks of Autauga Creek at Heritage Park
Dreamstime
Alabama is home to many critically imperiled species (those at very high risk of dying out completely). There are 51 high-priority watersheds across the state that contain more than 250 listed and at-risk fish, mussel, snail and crayfish species that are either at-risk or formally listed as threatened (high risk of becoming endangered) or endangered (high risk of extinction) under the Endangered Species Act. In fact, nearly 70 species of mollusks and fish have gone extinct (died out completely) in the last 80 years.
All of these factors contribute to the extensive conservation efforts that take place in Alabama in order to protect and restore aquatic habitats and biodiversity. Some conservation efforts have been immensely successful, including those listed below.
The tulotoma is a large freshwater snail that depends on clean, flowing water and rocky shoal habitat.
Problem: Between 1914 and 1966, six major dams were built on the Coosa River. They flooded the shallow rocky shoal habitat needed by the snail. By the mid-1900’s, the snail had disappeared from much of its historic range and was thought to be extinct in 1976.
The snail was federally listed as endangered under the Endangered Species Act in 1991. At this point, the Coosa River population below Jordan Dam (Elmore County) was restricted to roughly 1.8 miles of river. That stretch of river was impacted greatly by the dam’s infrequent water releases, causing very low flows for much of the day. That created problems with water quantity, temperature, and dissolved oxygen.
Solution: Beginning around 1990, Alabama Power established a minimum flow system below Jordan Dam to ensure more consistent waterflow downstream. An aeration system was also installed to improve dissolved oxygen. This nearly tripled the suitable and available habitat for tulotoma snail, and the snail population expanded into it.
In 2011, the population had recovered so well that the species was downlisted from endangered to threatened. Currently the species occupies nine stream reaches in the Coosa and Alabama River drainages.
While the snail is still absent from nearly 90% of its historic range and remaining populations are isolated and vulnerable, this is a true conservation success story as it proved that dam operations can be altered to protect wildlife and improve habitat.
Tulotoma Snails
Paul Johnson – AL Dept of Conservation and Natural Resources
Jordan Dam on the Coosa River (Elmore Co)
Alabama Power
The vermilion darter is a small, brightly colored freshwater fish found only in Turkey Creek and its tributaries in Jefferson County, Alabama, where it depends on clean, cool, flowing water and rocky stream-bottom habitat.
Problem: In the 1960’s-70’s, the darter was common in Turkey Creek. By the late 1980’s to early 1990’s, the fish was considered rare in Turkey Creek. Then, studies showed that development, sedimentation, pollution and impoundments were degrading and fragmenting the habitat.
In 1998, the county proposed the construction of a jail alongside Turkey Creek, and local conservationists were certain this would negatively impact the health of the vulnerable fish and its habitat. A local group called START (The Society to Advance the Resources of Turkey Creek) was formed to spearhead the efforts to block the construction of the prison and get federal protection for the fish.
Solution: The fish was federally listed as endangered under the Endangered Species Act in 2001. In 2010, a 13-mile stretch of the creek was designated as critical habitat. Land conservation became particularly important. Large portions of the Turkey Creek area were protected rather than developed, including what became the Turkey Creek Nature Preserve. in 2013, the 100-year old Old Shadow Lake Dam was removed, restoring more natural stream flow and reconnecting habitat. Banks were also restored and native vegetation planted to reduce erosion and runoff.
While the habitat is substantially better, protected lands have expanded, and the darter has demonstrated an ability to recolonize restored habitat, it is still listed as federally endangered. Its extremely small geographic range remains a major vulnerability. Still, this is a major success story, as it proves that combined effects of protecting the land, removing the dam, managing the fish, restoring the stream, and improving the watershed can have a positive impact on vulnerable and endangered species.
Vermilion Darter
John P Friel – iNaturalist
Turkey Creek
Jefferson County Greenways
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Jenkins, CN, KS Van Houtan, SL Pimm, JO Sexton (2015) US protected lands mismatch biodiversity priorities. PNAS 112(16), pp.5081-5086.
