Preamble

Water samples were collected from eight sites in a subwatershed of Crooked Brook on Totoket Mountain, North Branford, CT.  Two of these sites were in a wooded swamp and 6 were in streams flowing from the wetland to Crooked Brook ( see map showing sampling site locations ). The sites were chosen in order to have samples from areas above and below logging roads as well as in the wetland and in the streams.  We hoped observe differences in water chemistry from the wetland to the streams, differences due to logging activities in the area, and differences with changing precipitation.
 

Variables Selected

The following study variables were decided upon based on usefulness and ease of determination:  pH, temperature, conductivity, turbidity, chloride concentration, and nitrate concentration.  pH is a measure of the concentration of hydrogen (H+) ions in water, better known as the "acidity."  pH of 7 is neutral, while below 7 is considered acidic and above 7 is basic.  Most stream water falls around or below neutrality.  Conductivity is a measure of the concentration of all ions in a system.  The greater the amount of ions, the higher the conductivity.  Turbidity is a measure of water clarity.  The higher the turbidity, the higher the number of total suspended solids, and the cloudier the water is.  We chose to measure chloride and nitrate because they are readily measured using an ion chromatograph (IC).  Nitrate, specifically, is an important indicator of nutrient loading to a system.
 

Procedure

Samples were collected for 8 weeks in 120 mL plastic bottles which were rinsed with stream water at the sampling site 3 times before filling. We measured conductivity, temperature, and turbidity at the time of collection using the appropriate meters.  pH was measured once we got the samples back to the lab (2 to 3 hours after sample collection) using a pH meters.  (All meters used were borrowed from the local aquatic chemistry laboratory, thanks to Gaboury Benoit and Shimon Cohen-Anisfeld at Greeley Laboratories, of the Yale University School of Forestry & Environmental Studies).

All samples were preserved by freezing until mid-April when they were thawed and run through the IC. The IC detected concentrations of chloride (Cl^-) and nitrate (NO^3-) in micro-Molar (uM) which we then converted to mg/L. These data complement data gathered as part of the larger study (Ca, Mg, Na concentrations in stream water and precipitation) to provide a more complete description of stream water chemistry.

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