Project Watershed Central New York

Chemical water quality testing creates a "snapshot" of the water quality in a stream. Chemical monitoring tells us what is in the water at the place and time it was measured (Behar, 1996). However, by monitoring various chemical water quality parameters over time, it is possible to establish baseline data and determine if there are any changing trends in water quality. Chemical monitoring over time can be extremely useful for seeing how a watershed may be changing.

Project Watershed monitors nine chemical water quality parameters including dissolved oxygen, fecal coliform, pH, biochemical oxygen demand, reactive phosphate (PO4)^-3, nitrate (NOs)^-, chloride (Cl)^-, turbidity, and total dissolved solids. These parameters were chosen and adapted from the nine tests outlined in the Field Manual for Water Quality Monitoring (Mitchell and Stapp, 1997) in order to develop an overall Water Quality Index (WQI). However, there are three exceptions. Project Watershed tests for reactive rather than total phosphate, tests for total dissolved solids rather then total solids, and tests for chloride levels in place of monitoring temperature change as discussed in the Field Manual for Water Quality Monitoring. The importance of monitoring chlorides will be discussed at a later point in this section.Created in 1970 by the National Science Foundation, the WQI can be utilized to monitor water quality changes in a river or stream reach over time and determine whether the health of the stream is being maintained (Mitchell and Stapp, 1997). Additionally, this system allows individuals and volunteer groups to compare water quality data for different streams.

Following the completion of each test, the results are transferred to a weighting curve chart where a numerical value is obtained. Copies of the weighting curve charts utilized by Project Watershed CNY/SOS can be found in Mitchell and Stapp's text. This numerical value or "Q-value" is then multiplied by a weighting factor. Test parameters, such as dissolved oxygen, that are more significant in determining overall water quality health will have higher weighting factors. Once all the Q-value scores have been calculated for all nine tests, the values are totaled to arrive at an overall WQI (Mitchell and Stapp, 1997). This WQI value can then be used to determine the overall chemical health of the stream stretch. The table below gives the rating for the range of corresponding WQI results.

Source: NSF.org
2004

Additionally,
the results for each chemical test can be evaluated and assigned to one of the
following water quality categories: excellent, good, fair, and poor. The
following table provides a reference for comparing the test result for each of
the chemical parameters to a standard. This is important so that volunteers can
understand how water quality correlates with various chemical levels or
measurements. For example, very high levels of dissolved oxygen can have a
negative impact on a stream.

Source: Project
Watershed CNY/SOS, 1999; Milchell
and Stapp, 1997

Chemical
Survey

All water
samples should be taken in the main current in the middle section of the
stream, several inches below the surface of the water. During all chemical
monitoring and testing, volunteers are required to wear safety goggle and vinyl
gloves. One student (or individual) should record all the collected data and
results on the Chemical Water Quality Measurements form. The teacher retains
the results and should assess the Overall Chemical WQI using the Mitchell and
Stapp's Field Manual for Water Quality Monitoring (1997). All chemical
tests are conducted in the field at the sampling site. The Director completes
any tests that cannot be completed in the field. The Director at his/her home
lab completes the fecal coliform count and 5-day BOD test.

The results of
both tests are communicated to the teacher in charge so that he/she can finish
the overall assessment. The Director then completes the overall assessment to
determine the chemical WQI for the stream survey.

A copy of the
Chemical Water Quality Measurements Form used by Project Watershed CNY/SOS as
well as sample completed forms can be found in Appendix 3 of this report.

Chemical
Testing Equipment

Project
Watershed utilizes a DREL/2000 Portable Water Quality Laboratory, designed by
Hach Company, to conduct its chemical testing and monitoring procedures. The
Hach DREL/2000 unit includes a DR/2000 Spectrophotometer, Digital Titrator, pH
meter, Turbidimeter, Conductivity Pocket Pal, glassware, and all reagents and
apparatus needed for testing 21 chemical water quality parameters. Testing for
fecal coliform is conducted with a Hach Bacteriological Membrane/Filtration
(M/F) Lab. Table 3 provides testing and equipment information needed for each
of the nine chemical tests performed by Project Watershed.

Table 3.
Testing Methods Requirements