Douglas
Dam
The above coordinates will take you
to a shelter overlooking Douglas Dam. The area has parking,
bathrooms and picnic area. The water falling on the mountain side
not only forms branches and creeks but is fast moving and causes
erosion. This erosion carries soil and other material from the
mountain side and deposits it on the valley floor. The water cuts a
channel in the valley floor forming a river. This produces a
relatively flat area with a large water supply which is greatly
prized by humans. The same process is occurring on the other side
of the mountain creating a different watershed.
Each watershed has its own
characteristics. Some watersheds are very large like the
Mississippi basin which includes many smaller watersheds. Generally
small watersheds combine into progressively larger watersheds until
they empty into the ocean. Watersheds have boundaries which are
ridges or mountains which separate one watershed from another.
Terrain is also important. The steeper the watershed is determines
how fast the water flows and how much erosion occurs. Soil type is
another important factor. Sandy soil soaks up water and reduces
surface runoff. Clay is tighter and soaks up less water increasing
runoff and erosion.
In an area where the boundaries are
close together a dam may be built. At the above coordinates the
boundaries are close enough to allow the construction of Douglas
Dam across the French Broad River.
The French Broad flows through the
Appalachian Mountains which are the oldest mountains in the world.
The Appalachian Mountains were old before the Rockies were formed
and the French Broad is a very old river. It is so old it is
practically devoid of fossils. It is actually the third oldest
river in the world. Only the Nile in Egypt and the New River in
West Virginia are older.
The French Broad begins near Rosman,
North Carolina and flows 116 miles through North Carolina into
Tennessee. The Tennessee section travels 102 miles until it meets
the Holston River just east of Knoxville. Where these two rivers
meet it becomes the Tennessee River and a new watershed.
Douglas Dam has a long and
interesting history and shows an important use of the French Broad
watershed. In 1933 the federal government initiated a golden era of
dam construction in the United States, a wave of construction that
included the Grand Coulee Dam and the Hoover Dam. The same year the
Roosevelt administration established the Tennessee Valley Authority
(TVA) to provide much needed hydroelectric energy to the Tennessee
Valley area.
During World War II electrical power
was needed for national defense purposes, specifically for the
Manhattan Project atomic weapons plants in Oak Ridge TN. The
Manhattan Project resulted in the development of the first nuclear
weapons, and the first-ever nuclear detonation, at the Trinity test
of July 16, 1945.
In 1941 President Roosevelt asked
Congress to approve funding for Douglas Dam in east Tennessee.
After the attack on Pearl Harbor funding was quickly approved and
the dam was built as a rush project. Douglas Dam was built in 12
months and 17 days.
According to TVA "the construction of
Douglas set a world record for project of equivalent size." TVA
directs operations of more than 50 dams in parts of Alabama,
Virginia, Kentucky, Georgia, North Carolina, Mississippi and
Tennessee. Tennessee, in the East South Central region of the
United States, lies between the Mississippi River on the west and
the backbone of the Blue Ridge province of the Appalachian
Mountains on the east. The French Broad river in the southeastern
United States, rising in western North Caroline near the foot of
the Blue Ridge Mountains. It flows north past Asheville and then
northwest into eastern Tennessee, where it joining the Holston
River near Knoxville to form the Tennessee River. The total length
of the French Broad River is 250 miles. The Tennessee River, is a
tributary of the Ohio River. The Tennessee River is formed by the
confluence of the Holston and French Broad rivers, just east of
Knoxville, TN. It flows 652 mile in a great U shape, south into
Alabama, then turning north to pass through western Tennessee and
Kentucky, where it joins the Ohio River near Paducah. The river has
a drainage basin of some 39,000 miles Since the establishment of
the TVA in 1933, the river has been extensively dammed for
navigation, flood control and power production.
Douglas Dam is a hydroelectric power
generation facility consisting of 4 electric generation units with
combined production capacity of 165,600 kW. kW is a measure of
power - kilowatt. The electrical generator is a device that
converts mechanical energy to electrical energy, generally using
electromagnetic induction.
In addition to power generation, a
secondary purpose of Douglas Dam is flood control of the French
Broad River. The Douglas reservoir extends 43 miles upriver from
the dam through the foothills of the Great Smoky Mountains. Douglas
Lake has over 513 miles of shoreline and has a water surface of
approximately 30,000 acres. Flooding storage capacity is 1,081,000
feet of water. Under normal conditions, Douglas stores spring
rainwater for the release during the dry summer and fall months to
maintain adequate depth for navigation on the Tennessee River and
to generate electricity. Water levels begin dropping in the late
summer to provide space for the next spring's rain. The water level
in Douglas Reservoir varies about 41 feet in a normal
year.
One problem encountered by dams
involves the natural processes of erosion and sediment transport.
Erosion occurs naturally in the environment when water transports
solids like sediments, soil, and rock. This affects the water on
both the upstream and downstream side of the dam.
All dams and reservoirs trap
sediments above the dam. These sediments, especially gravel and
cobble, collect behind the dam. This buildup of sediments will fill
the reservoir over time. Some dams may use low level outlets to
combat this problem.
Below the dam water carries away the
easily erodible materials and this changes the streambed. The
streambed is said to be armored with rocks. The effect tends to
make the streambed deeper and narrower. The river tends to become a
straight single channel.
As far as Ecological Impacts - one of
the issues of hydroelectric power generation is a reduction of
dissolved oxygen in the dam tailwaters. Three systems are used at
Douglas Dam to improve oxygenation.
1. Turbine venting - injection of
oxygen at the turbines.
2. Surface water pumps - pumps that
push surface water downward to the turbines.
3. Water pulsing - release of water
through turbines to maintain some water flow at all
times.
The reservoir remains an integral
unit in the overall water control system in the Tennessee Valley.
The water used to generate power at Douglas is used again and again
at the nine TVA hydroelectric plants located along the Tennessee
River from Knoxville to Paducah, KY.
Douglas Lake is a popular
recreational destination for up to 2 million visitors a year.
Primary uses are fishing, boating, water skiing, camping, hiking
and wildlife viewing. Birdwatchers enjoy the fall migration of
shore birds, wading birds and other waterfowl that flock to Douglas
from late July to early October. The birds rest and feed in the
muddy shoreline and areas of shallow water exposed as the level of
the reservoir is lowered to prevent spring flooding downstream. In
addition to a number of private campgrounds, TVA maintains the
Douglas Dam Headwater Campground and the Douglas Dam Tailwater
Campground for public use.
The above coordinates will take you
to a shelter overlooking Douglas Dam. The area has parking,
bathrooms and picnic area.
To claim credit
for the cache find, you must do the following:
Take a picture
of yourself with your GPSer and the Dam visible in the background.
Post this picture with your log.
Then email me
with the answers to the following questions. This information can
be obtained from the information boards at the overlook.
1. What is the
Dam height?
2. What is the
Dam Length?
3. What are the
4 TN Valley Watershed Visitors Centers?
Handicapped accessible with
restrooms, vending machines, parking and picnic
areas.