Physical Parameters

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  • Stream discharge, or flow, is measured in cubic feet per second.
  • A coefficient of .8 was given to sites with a rocky bottom and .9 to sites with a muddy bottom.
  • There is an influx in velocity and discharge over distance throughout both streams.
  • Of the documented velocities and discharges, Site 1A has the lowest flow for each stream.
    • Sites 1A and 1B are the headwaters for the streams; they are very shallow.
  • Stream velocity could not be measured at Long Island Creek Site 1B and Marsh Creek Sites 6A and 6B because:
    • Long Island Creek Site 1B: stream depth was shallow and rocks interrupted the movement of testing materials (ping pong ball).
    • Marsh Creek Sites 6A and 6B: inflow from the Chattahoochee River interfered with data collection.

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  • Relative humidity indicates how moist the air is; it is measured on a scale from 0-100%.
  • Typically, the higher the temperature, the greater the capacity for the air to hold water.
  • Stream averages throughout the sampling periods:
    • Long Island Creek: 25˚C and 79% relative humidity
    • Marsh Creek: 23˚C and 81% relative humidity
  • Marsh Creek Site 1B experienced the lowest air temperatures because it is not exposed to direct sunlight.
    • Shaded areas with a lack of air flow can experience low temperatures and high relative humidity.

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  • Conductivity measures the ability of water to conduct an electrical current.
  • The presence of inorganic dissolved solids, like metals, affects the conductivity reading.
  • Long Island Creek Site 3B has the highest conductivity average amongst the other sites.
    • This site is located in a dense commercial area; a bridge runs over it.
    • Runoff from impervious surfaces can attribute to the high conductivity levels.
  • Marsh Creek Site 3B has the lowest conductivity averages amongst the other sites.
    • This site is much more secluded than the other sites; it is located on the Glenridge Hall property.
    • Here, there are more natural barriers that can help filter out pollutants before runoff makes it to the stream.


Chemical Results - 2013

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Acidity is measured by pH on a scale of 1 (extremely acidic) to 14 (extremely basic) with 7 being neutral. The EPA suggests a range between 6 and 9 to support life in a stream.
  • At both Marsh Creek and Long Island sites pH was measured close to 7
  • The lowest readings were measured between 6.2 and 6.4 at Long Island site 1 where very little water was present and mostly stagnant, and Marsh Creek site 3 where the land is less disturbed and heavily vegetated.


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Measured in parts per million (ppm), dissolved oxygen (DO) is used by aquatic plants, animals, and other organisms and is heavily dependent upon water temperature and flow. The lower the water temperature, the higher capacity the stream has for carrying dissolved oxygen, and as water moves faster it can absorb more oxygen. Conversely, the presence of decomposing organic material may lower the dissolved oxygen content of a stream. As low as 4ppm of DO will support life, however 6-8ppm is ideal.
  • Only Marsh Creek location 1A and Long Island locations 1A, 1B, and 3A tested lower than ideal
  • All site 1 locations with low DO had very little flowing water, and organic matter was observed in the stream at these locations
  • Long Island location 3A has an illegal waste dump problem which may include organic matter contributing to a lower DO content
  • While higher DO levels are usually associated with cooler water temperatures, in our urban streams it is likely that we see different correlations because impervious surfaces increase both the temperature of run off and the quantity of run-off which in turn increases the speed of the stream


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Measured in ppm, nitrate-nitrogen is a nutrient pollutant resulting from human and animal waste, decomposing organic material, and fertilizers. Levels of less than 1ppm are considered unpolluted and water tested above 10ppm is considered unsafe for drinking.
  • Long Island location 5A and Marsh Creek locations 3A 3B and 3Pond all tested at unpolluted levels
  • Long Island site 2 locations tested at over 13ppm, possibly because a steep slope at their test site is fenced in for a resident's dogs
  • Long Island location 1B also tested relatively high, likely from decomposing grass clippings dumped at the site
  • Marsh Creek site 4 and location 1A tested the highest at just around 3ppm: 1A may be due to fertilizer or decomposing organic material while site 4 was located adjacent to a dog park at an apartment complex


Phosphate

1A
1B
2A
2B
3A
3B
3P
4A
4B
5A
5B
6A
6B
Long Island
<1
0
0
0
0
0
N/A
0
0
0
0
0
0
Marsh Creek
0
0
0
0
0
0
0
0
0
0
0
0
0
Measured in ppm, phosphate is also a nutrient pollutant resulting from animal waste, organic material, and fertilizers. High phosphate levels may also be from industrial soaps. Only Long Island location 1A tested positive for phosphate, and only on one occasion at very low levels. While the lack of phosphate is a good thing and we are not concerned about it presently, our data helps establish a baseline and will be important in future monitoring if the streams do begin testing positive.


Bacterial Results

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High E.coli levels indicate pollution problems from run-off or sewage; anything over 1,000 CFU/100ml must be re-tested and if found again, reported to AAS. Counts over 576 CFU are considered unsafe for even occasional recreational use. Counts over 235 CFU are considered high and correlate to 8 incidents per 1000 people.
  • Our counts at both Long Island and Marsh Creek were consistently measured above 1000 CFU
  • The highest counts from our final week's samples, which were taken after a storm even which increased run-off
  • Previous weeks' counts declined likely due to a lack of rainfall