FIELD WORK

Turbidity

Turbidity is the measure of the relative clarity of water. Turbidity water is caused by suspended and colloidal matter such as clay, silt, organic and inorganic matter, and microscopic organisms. Turbidity should not be confused with color, since darkly colored water can still be clear and not turbid. Turbid water may be the result of soil erosion, urban runoff algal blooms, and bottom sediment disturbances which can be caused by boat traffic and abundant bottom feeders.

Turbidity Procedure

The water testing kit container is used to perform the turbidity test.

  • Remove the backing from the secchi disk icon sticker.

  • Adhere sticker on the inside bottom of the large white jar (kit container) Position the sticker slightly off center.

  • Fill the jar to the turbidity fill line located on the outside kit label.

  • Hold the Turbidity Chart on the top edge of the jar. Looking down into the jar, compare the appearance of the secchi disk icon in the jar to the chart. Record the result as Turbidity in JTU.

    Ranking Test Results

    Rank the results of each water quality test on a 1 4 scale:

    Test factor: Result: Rank:

    dissolvedoxygen

    91 110% Sat
    71 90 % Sat
    51 70 % Sat
    <50 % Sat
    4 (excellent)
    3 (good)
    2 (fair)
    1 (poor)
    BOD 0 ppm
    4 ppm
    8 ppm
    4 (excellent)
    3 (good)
    2 (fair)
    Coliform
    Bacteria
    negative
    positive
    3 (good)
    1 (poor)
    PH 4
    5
    6
    7
    8
    9
    10
    I (poor)
    I (poor)
    3 (good)
    4 (excellent)
    3 (good)
    I (poor)
    I (poor)
    temperature change 0 - 2*C
    3 - 50*C
    6 -10*C
    >10*C
    4 (excellent)
    3 (good)
    2 (fair)
    1 (poor)
    nitrate 5 pprn
    20 ppm
    40 pprn
    2 (fair)
    1 (poor)
    1(poor)
    phosphate 1 ppm
    2 ppm
    4 ppm
    4(excellent)
    3 (good)
    2 (fair)
    turbidity 0 - 4
    >0 to 40
    >40 to 100
    >100
    (excellent)
    3 (good)
    2 (fair)
    1 (poor)

    Use the ranked results to track water quality trends over long periods of time, to compare the water quality at different sites along the river, and to investigate how land use affects water quality.