2. Goal
• Use ArcGIS to determine most polluted
watershed in Fairfax County, VA.
• Use ArcGIS to evaluate most polluted areas in
watershed, to prevent further degradation and
take active measures to improve water quality.
• Use data on pollution sources which cause water
pollution and assess current watershed
conditions in Fairfax County.
• High population density, percentage impervious
cover and low habitat quality of water means
more polluted watershed.

3. Data
• Collected data on human population, pet population and
watersheds of Fairfax County.
• Data Sources-
1. Fairfax County watersheds and streams shapefiles downloaded
from www.fairfaxcounty.gov
2. Fairfax County Population data from website
http://factfinder2.census.gov
3. Pet Population data from www.avma.org
4. Watershed Imperviousness and Habitat Quality data from
http://www.fairfaxcounty.gov/dpwes/watersheds/
• The projected Coordinate System used for Fairfax County is NAD
1983 StatePlane Virginia North FIPS 4501 Feet.

4. Input Factors
• Human Population Density
• Pet Population Density
• Watershed Imperviousness
• Watershed Habitat Quality

5. Human
Population
Density
Pet
Population
Density
Watershed
Impervious-
ness
Watershed
Habitat
Quality
Intersect
layers
Most Polluted
Watershed
Sites
High Human
Population
Density Areas
High Pet
Population
Density Areas
High
Imperviou-
ness Areas
Very Poor
Habitat
Quality Areas
Export
Export
Export
Export

6. Watersheds of Fairfax County
• Accotink Creek
• Belle Haven
• Bull Neck Run
• Bull Run
• Cameron Run
• Cub Run
• Dead Run
• Difficult Run
• Dogue Creek
• Four Mile Run
• High Point
• Horsepen Creek
• Johnny Moore Creek
• Kane Creek
• Little Hunting Creek
• Little Rocky Run
• Mill Branch
• Nichol Run
• Occoquan
• Old Mill Branch
• Pimmit Run
• Pohick Creek
• Pond Branch
• Popes Head Creek
• Ryans Dam
• Sandy Run
• Scotts Run
• Sugarland Run
• Turkey Run
• Wolf Run

14. Conclusions
• Cameron Run watershed is the most polluted
watershed in Fairfax County.
• Among the three polluted sites in Cameron Run
Watershed, Site2 is most polluted.
1. It is having highest population density among
other sites.
2. It is near Lake Bancroft, where the main streams
of Cameron Run Watershed (Holmes Run and
Tripps Run) fall.
• Site2 needs active measures for preventing
further degradation and improving water quality.

15. Suggestions for Further Research
• Identifying the possible impact of industries
and swimming pools on watersheds.
• I was unable to assess chemical quality of
stream water.
• Additional analysis could be done on storm
water and flood plains.

16. References
• GIS Data Layer Information – Fairfax County, Virginia (Data
updated on 8/21/2014 )
http://www.fairfaxcounty.gov/maps/metadata.htm
• Fairfax County 2010 Census Tracts Population
http://factfinder2.census.gov
• U.S. Pet Ownership Statistics (2012)
https://www.avma.org/KB/Resources/Statistics/Pages/Mar
ket-research-statistics-US-pet-ownership.aspx
• Watersheds - Fairfax County, Virginia
http://www.fairfaxcounty.gov/dpwes/watersheds/
• Stormwater Management Status Report (2013)
http://www.fairfaxcounty.gov/dpwes/stormwater/stormwa
ter_status.htm