Lake Jackson Water Quality Reports
Background: In 2017, the water quality in the lake became a popular topic of discussion. The LJCA president at the time, Jim Trengrove, worked with resident Scott Lewis to reach out to several agencies, and found that there was little information found. To provide answers to neighbors, family, and friends, Scott began testing the water in Lake Jackson. Testing was done in conjunction with the Prince William County Soil & Water Conservation District (PWCSWCD). The Soil & Conservation District staff provided some testing supplies.
Tests were conducted in July and September 2017 and 2018, and Scott reported his findings at Citizens Association Meetings.
Three test sites were used:
○ Site 1: About 100 yards upstream from Big Beach, center of waterway, perpendicular from dock extending from house with green multi-level boathouse.
○ Site 2: Center of waterway, perpendicular from dock of Linda & Terri Best
○ Site 3: Center of waterway, perpendicular from dock of Scott & Jewel Lewis.
Results from July to September 2017:
● Improved turbidity (clarity of water)
● Improved pH (goal is around 7)
● Cooler water and 4ppm indicates oxygen saturation levels down to 50% (goal is higher)
Coliform Bacteria : This test checks for bacteria, commonly including "e. coli" . The coordinator said that she would be shocked if we were NOT positive, since most waterways test positive. This test came out positive, but test only shows "positive" or "negative". Water folks indicated that this test is almost always positive, and tests that measure more precisely get more expensive.
Turbidity (particulates in water) 30-40 on a scale that appears to go from 0 to 100. In layman's terms: fairly cloudy. Turbidity is the measure of the relative clarity of water. Turbid water is caused by suspended and colloidal matter such as clay, silt, organic and inorganic matter, and microscopic organisms. Turbid water may be the result of soil erosion, urban runoff, algal blooms, and bottom sediment disturbances which can be caused by boat traffic or high flow rate of water.
Dissolved Oxygen : 4 ppm which at this temperature water (30C) shows our oxygen saturation level at 50-63%, which is low. In layman's terms, more oxygen is better, with 100% being perfect. Lower oxygen shows more decay, more floating stuff, and less ability for water and
wildlife to thrive. Dissolved oxygen is important to the health of aquatic ecosystems. Waters with high dissolved oxygen levels are most likely healthy and stable environments.
http://www.waterontheweb.org/under/waterquality/DOSatCalc.html using 226 feet above sea level.
pH : Readings of 8.5 and 9
Waterways are normally 6.5-8.5, so the higher pH confirms we have naturally hard water.
Results Interpretation:
-Agricultural run-off is indicated as significant source
-E.coli dissipates downstream
-Rainfall generally boosts agricultural impact
What’s Next?
-Continued E.coli monitoring
-Seeking streams that flow consistently
-Low water levels should make identification easier
-Identified streams to be tested in October and November 2018
Volunteers needed to help.
Contact: [email protected]
Testing and report by Scott Lewis
Background: In 2017, the water quality in the lake became a popular topic of discussion. The LJCA president at the time, Jim Trengrove, worked with resident Scott Lewis to reach out to several agencies, and found that there was little information found. To provide answers to neighbors, family, and friends, Scott began testing the water in Lake Jackson. Testing was done in conjunction with the Prince William County Soil & Water Conservation District (PWCSWCD). The Soil & Conservation District staff provided some testing supplies.
Tests were conducted in July and September 2017 and 2018, and Scott reported his findings at Citizens Association Meetings.
Three test sites were used:
○ Site 1: About 100 yards upstream from Big Beach, center of waterway, perpendicular from dock extending from house with green multi-level boathouse.
○ Site 2: Center of waterway, perpendicular from dock of Linda & Terri Best
○ Site 3: Center of waterway, perpendicular from dock of Scott & Jewel Lewis.
Results from July to September 2017:
● Improved turbidity (clarity of water)
● Improved pH (goal is around 7)
● Cooler water and 4ppm indicates oxygen saturation levels down to 50% (goal is higher)
Coliform Bacteria : This test checks for bacteria, commonly including "e. coli" . The coordinator said that she would be shocked if we were NOT positive, since most waterways test positive. This test came out positive, but test only shows "positive" or "negative". Water folks indicated that this test is almost always positive, and tests that measure more precisely get more expensive.
Turbidity (particulates in water) 30-40 on a scale that appears to go from 0 to 100. In layman's terms: fairly cloudy. Turbidity is the measure of the relative clarity of water. Turbid water is caused by suspended and colloidal matter such as clay, silt, organic and inorganic matter, and microscopic organisms. Turbid water may be the result of soil erosion, urban runoff, algal blooms, and bottom sediment disturbances which can be caused by boat traffic or high flow rate of water.
Dissolved Oxygen : 4 ppm which at this temperature water (30C) shows our oxygen saturation level at 50-63%, which is low. In layman's terms, more oxygen is better, with 100% being perfect. Lower oxygen shows more decay, more floating stuff, and less ability for water and
wildlife to thrive. Dissolved oxygen is important to the health of aquatic ecosystems. Waters with high dissolved oxygen levels are most likely healthy and stable environments.
http://www.waterontheweb.org/under/waterquality/DOSatCalc.html using 226 feet above sea level.
pH : Readings of 8.5 and 9
Waterways are normally 6.5-8.5, so the higher pH confirms we have naturally hard water.
Results Interpretation:
-Agricultural run-off is indicated as significant source
-E.coli dissipates downstream
-Rainfall generally boosts agricultural impact
What’s Next?
-Continued E.coli monitoring
-Seeking streams that flow consistently
-Low water levels should make identification easier
-Identified streams to be tested in October and November 2018
Volunteers needed to help.
Contact: [email protected]
Testing and report by Scott Lewis