Virtual Tour of the Rivanna River Watershed
1-4
The Rivanna River begins in the Blue Ridge Mountains and flows east to become the
largest tributary of the James River. The South Fork of the Rivanna River is fed by two
large tributaries, the Mechums and the Moormans Rivers, in Albemarle County. The
North Fork of the river has its origins in Greene County. The South Fork has been
dammed to form the South Fork Reservoir to the north of Charlottesville, and is an
important source of water in the urbanized part of Albemarle County. The two forks of
the river join near Charlottesville, and the main stem of the river flows southeast into
Fluvanna County. The Rivanna crosses Fluvanna County through Palmyra, and flows
into the James river near the Town of Columbia.
5-7
A watershed is an area of land where all rainwater runoff runs downhill to the same body
of water. In the example, a red line marks the highest points along the ridges around the
watershed. Water flows downhill through small streams and into larger one until they all
converge at one point at the bottom of the watershed (a bay or large river in this case).
8-9
The next two slides show the location of the Rivanna River Watershed in the
Commonwealth of Virginia, a map of the watershed showing its location in the four
counties of Greene, Albemarle, a corner of Louisa and Fluvanna.
10-12
Smaller watersheds are always part of larger watersheds. The Rivanna River flows into
the James River, so the Rivanna River Watershed is part of the larger James River
Watershed. The James River, in turn, flows into the Chesapeake Bay, which makes up the
largest watershed on the east coast of the Untied States (occupying parts of six states, and
the District of Columbia).
13-18
The land in the watershed was once totally covered in forest. When the land was settled,
much of it was cleared for farming, and more recently farmland is being subdivided for
residential development. The last slide in this series shows a residential subdivision being
built next to Lickinghole Creek near Crozet in Albemarle County. Lickinghole Creek is a
tributary of the Mechums River.
19-24
With development comes the potential for pollution of the waters of the Rivanna River
and its tributaries. Three of the most common types of water pollution in the watershed
(and the Chesapeake Bay Watershed in general) are sediment, nutrients and bacteria.
 Sediment: soil washed into streams through erosion
 Nutrients: principally nitrogen and phosphorous, found in fertilizers as well as
human and animal waste
 Bacteria: usually contributed by human and animal waste
Examples of erosion and a source of animal waste follow.
25-27
A list of sources of nutrients in water resource.
 Livestock
 Over-fertilized cropland
 Over-fertilized suburban lawns
 Pet waste
 Failing septic systems
 Wastewater treatment plant outflows
Followed by a photograph of algae growth caused by an abundance of nutrients in the
water, and another of the dangers of allowing access to streams by livestock.
28-32
A map showing stream segments that have been listed as impaired by high levels of E.
coli bacteria. The following slides show creatures that use the water and some of the
ways that people use the water in the watershed. This is an opportunity to have students
think of other ways we use water: watering lawns and gardens, washing cars, putting out
fires, cooking, manufacturing, etc.
33-34
The next section discusses how development increases the flow of runoff into streams
and rivers. Impervious cover, such as parking lots, roads and sidewalks, does not allow
rainwater to seep into the earth. Runoff from these surfaces washes many types of
pollution into streams.
35.
The increased amount of runoff that results from development also harms streams and
rivers, eroding stream banks and scouring river bottoms. The 3rd photo on the slide shows
a pipe that carries stormwater from a parking lot or road into a stream. When the pipe was
installed, it rested on the bottom of the stream. As a result of erosion caused by an
increase in flows during rainstorms, the stream bottom and banks have eroded away and
the pipe has been left hanging in the air.
36
An increase in impervious cover also results in flooding when there is no place for the
increase in runoff to go.
37-40
To prevent flooding, stormdrains are built to carry runoff directly into a stream or river.
The 2nd slide shows 2 pipes and a flume carrying stormwater runoff into streams and
rivers. The 3rd slide shows a stormwater pond for a residential subdivision. Stormwater
ponds hold runoff and let it out into a stream or river more slowly through a pipe. The
total quantity of the outflow remains the same, but the amount of water in peak flows is
reduced, reducing the damage cause by increased runoff. The 4th slide in the series shows
a cluster of five stormwater basins built to handle runoff from intensive development on
Pantops, near Charlottesville.
41-43
Some solutions are suggested for preventing water pollution, as well as the flooding and
stream damage caused by increased runoff resulting from development. The first is the
preservation or planting of forested buffers along streams and rivers. Slide #43 shows a
portion of the forested buffer around the South Fork Reservoir outside Charlottesville that
was removed by a landowner interested in improving the view from his house. The buffer
around the reservoir is protected by law, and the landowner was required to replant the
portion of the buffer that he had removed. Forested buffers play many roles in protecting
water quality. They hold soil in place, shield the ground from the impact of raindrops,
allow runoff to soak into the ground and recharge the groundwater, filter out particles of
sediment and other pollution, and absorb nutrients for use by trees and other plants.
44-46
A rain garden is dug into a naturally-occurring low spot in a yard. The bottom of the hole
is filled with a foot of sand, 2-3 feet of soil mixed with compost fills the rest, native trees
and shrubs are planted and 3-4 inches of mulch are placed on top. The rain garden:
 Filters out particles of pollution
 Takes in nutrients
 Bacteria and fungus in the soil breaks down many pollutants
 Stores excess water
 Allows runoff to recharge the groundwater
Slide #46 shows how runoff from a driveway is filtered by grass and enters a rain garden.
If the rain is heavy, the rain garden fills and the excess runoff is again filtered as it runs
down a grassy swale. A second rain garden is sited to absorb and process more runoff,
and any excess runs into a storm drain, reduced in quantity and improved in quality.
47
Rainwater harvesting refers to collecting and storing rainwater for later use. A 2-inch rain
that that is collected from the average roof provides enough water for one person to use
for a month.
48-50
There are various ways rain can be "harvested" from a rood. One rain barrel is easily
filled during a short rain storm. Connecting a number of rain barrels can collect and store
enough water to carry the homeowner through a dry spell. Large cisterns or water tanks
can store enough water for indoor use when properly filtered and sterilized.
51
The slide of retention basins on Pantops is repeated to suggest that if every home and
business in the picture had rain barrels or cisterns collecting rain water, the need for such
retention basins would be reduced.
52-59
A virtual tour of the Rivanna River Watershed. Starting with the Moorman's River
Watershed, which has its origins in the Blue Ridge Mountains in western Albemarle and
Green Counties. A dam on the Moorman's River nestled in the mountains in Sugar
Hollow forms a reservoir used by the City of Charlottesville and urban parts of
Albemarle County. Slide #55 shows the Moorman's River above the reservoir. Slides #56
and #57 show the reservoir where the river enters on the right side and is released over
the dam on the left. The Moorman's River wends its way through rural Albemarle County
(#58) and joins the Mechum's River shortly before it flows into the South Fork of the
Rivanna River (#59).
60-63
Slides of the South Fork of the Rivanna River and the South Fork Reservoir. Slide #63
shows the dam on the reservoir and the water treatment plant (on the left) that supplies
most of Charlottesville's water supply.
64-67
Slides of the North Fork of the Rivanna River, which has its origins in Greene County.
The northern part of this tributary flows through rural countryside. As the North Fork get
closer to Charlottesville signs of development appear. Slide #67 shows a newly built
house in the Advance Mills Subdivision. Along the bank of the river on the left side of
the photo a strip of yellowish vegetation can be seen. This is a 200-foot riparian buffer
that has been put under permanent easement to protect the river. The vegetation in this
buffer will be allowed to grow naturally until it is once again forested.
68-73
The South Fork and the North Fork of the Rivanna River join northeast of the City of
Charlottesville to form the Rivanna River proper. The Rivanna flows down the east side
of the city and then southeast through rural Albemarle County and Fluvanna County.
Slide #70 shows the Moores Creek Waste Water Treatment Plant, which empties into
Moores Creek (Slide #71) just west of its confluence with the Rivanna. Slide #72 is
Albemarle county and #73 is Fluvanna County.
74-75
Slides #74 and 75 show Lake Anna, formed by damming Boston Creek, a tributary of the
Rivanna. Lake Anna is a very large subdivision of approximately 7,000 people. Slide #77
shows where the Rivanna River flows into the James River near the small town of
Columbia.