Potomac River

By: Josh Bennett, Christian Allen, Cole Gifford

Demographics of the area-past and present; what kind of human activities are there that affect it?

The population of the Potomac basin is about 6.11 million people and has increased by about five percent since 2005. The average population density is 84 people per square mile and in the late 1500s, the average population density was 2.2 people per square mile. People living in urban areas account for the most of the basin’s residents at almost 81% of the population. Those living in rural areas make up 18.6% of the population, while those living on farms only account for 0.7%. The basin’s major industries include agriculture and forestry throughout the basin, coal mining and pulp and paper production along the North Branch Potomac River, chemical production and agriculture in the Shenandoah valley, high-tech, service, and light industry, as well as military and government installations in the Washington metropolitan area, and fishing in the lower Potomac estuary. http://www.potomacriver.org/potomac-basin-facts

How is the land along the river used?

It is used for building things for the growing population (office buildings, streets, parking lots, etc.) in the suburban areas along the river. http://www.wwdmag.com/flowmeters/flowmeter-installed-improve-water-quality-potomac-river

Potomac River

What kind of surfaces are present?

Most of the basin’s land area is covered by forests at 57.6% of the land area. Developed land makes up 4.8% of the basin’s land area and agriculture cover 31.8%. Water and wetlands make up 5% of the basin’s land area. http://www.potomacriver.org/potomac-basin-facts/

What is the elevation of the land around the river? How does it compare to the area around it?

Near the base of Backbone Mountain in West Virginia, the Potomac River runs out of a spring 3,140 feet above sea level. Marked by the Fairfax Stone, the spring is not moving very fast. From here the river begins its swift decent through the highlands of West Virginia and Maryland, joined by other streams flowing quickly off the steep slopes. Then it is joined by the Savage River forty-six miles from the source and has already dropped 2,000 feet in elevation. http://www.growingnative.org/pdfs/Curriculum/1.5.SP2.pdf

How do (3) and (4) affect the amount of runoff and groundwater? What are the effects of these on the river?

If the surfaces are not non-pervious like concrete, there wouldn't be much runoff. For example, if there was a wetland there would not be much runoff because the water would stay in the wetland but if it was concrete or pavement, there would be a lot of runoff because it is a non-pervious surface. If the elevation creates an upward slope, there won't be any runoff because water cannot travel up hills. If the elevation creates a downward slope, there will be more runoff because water travels easier downhill. Also, if there a lot of impervious surfaces, there would not be as much groundwater. Runoff can also cause a river to flood.
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What kind of pollutants affect the river? (point source/non-point source)

Point source pollution greatly affects the Potomac River. It comes from nutrients and sediment from runoff from other streams. The Potomac flows through urban areas, so when it rains, runoff carries nutrients and sediment into the river and as a result marine life is killed. Farms are using chemical fertilizers and manure, which flows into the river and creates waste water. This flows into sewage drains and into the river which will create dead zones, and fish hormone levels go up and they will start laying eggs. http://www.epa.gov/oaqps001/gr8water/xbrochure/chesapea.html

How has the quality of the water in the river changed?

At first, there were no farms or buildings around the river. Then farms and houses were built causing fertilizer to go into sewage drains. As a result, it ends up in the Potomac River and causes the water to be polluted. The average healthy depth for a river or a bay is 0.08. The Potomac River turbidity is 1.7 which is very unhealthy for the river, and means you can barely see through the water. The average temperature depending on the type of month ranges from 36.5F-76.5F which is higher than the average, and some species' population can decrease because of the water temperature. The average DO (dissolved oxygen) levels of the Potomac River are 14.5-13.3. Since so much DO is in the river, it is good for the marine life, but if too many nutrients and sediment build up in the river, it could kill off the marine life. The average ph levels of the Potomac River are 7.7-7.8. That is the best it can be on average and the levels are good for marine life. Macro-invertebrate are present in the Potomac, and River Fairfax County says that contaminates levels are very high, so this means that the the macro-invertebrate will start killing marine life which will ruin the ecosystem in the river.
http://www.epa.gov/oaqps001/gr8water/xbrochure/chesapea.html http://www.fairfaxcounty.gov/nvswcd/newsletter/streammonitor.htm


How do these changes in water quality affect the living things in the ecosystem?

Two effects of the changes would be that nutrients and sediment cause all the marine life to die, and the rain water pollutes the bay which makes fish hormone levels rise and causes male fish to lay eggs. Underwater sea plants can't get enough oxygen and die, which makes underwater species have no food sources. The Potomac River has the average rainfall of 42 inches, and because the rain is so polluted, when it gets into the river it causes the fish hormone levels to go up and causes the male fish to lay eggs. http://www.fairfaxcounty.gov/nvswcd/newsletter/streammonitor.htm
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What types of measures are being taken to improve the water-quality that benefit the watershed?

A flowmeter was installed in the Potomac River to measure sewage discharge from the Blue Plains Advanced Wastewater Treatment Plant to improve water quality. The NOAA is also researching and have come up with a way to reduce the amounts of nitrogen in the water as well as reduce the amounts of algae, by growing oysters on the riverbed. http://www.wwdmag.com/flowmeters/flowmeter-installed-improve-water-quality-potomac-river

How do all of the above impact the Bay (negatively or positively)

The Potomac River is one of the 3 rivers with the highest flow, and these three rivers contribute the largest nutrient load to the Chesapeake Bay Basin. These nutrients cause too much algae to grow, and the algae use alot of the oxygen that other plants and fish need to survive. This impacts the bay negatively. http://www.noaanews.noaa.gov/stories2014/20140409_oysteraquaculture.html