Project Watershed Central New York

Data Quality Objectives for Measurement Data

This section will discuss how accurate, precise, complete, comparable, and representative the project’s data are.  Data quality objectives were adapted from other volunteer monitoring organizations’ QA/QC plans (Pennsylvania Department of Environmental Protection, Southern California, Dutchess County Wappinger Creek Program, Alliance for the Chesapeake Bay, River Watch Network). 

The data collected by Project Watershed CNY/SOS are primarily used by regional high school teachers and their students for educational purposes.  In some instances the data will be utilized by the Onondaga County Council on Environmental Health for inclusion in the county’s Nonpoint Source Pollution Control Program and Water Quality Strategy Report. 

Chemical indicators have been adapted from the nine protocols outlined in the Field Manual for Water Quality Monitoring (Mitchell and Stapp, 1997).  All benthic macroinvertebrate sampling/monitoring is done in accordance with the procedures outlined by the Izaak Walton League of America SOS program. 

Source: Hach Chemical Company Lab Manuals

In 1998 and 1999, Project Watershed CNY/SOS conducted informal split sampling with the Onondaga County Health Department lab as part of an internal check process.  The accuracy of chemical measurements are also checked by performing tests on standards for quality control.  The standards are obtained through the Hach Company.  Currently, the Director conducts tests on standards on an average of every six months or when a new bulk shipment of chemicals is received.

Accuracy

Accuracy refers to the measure of how close test results are to a true or expected value.  Accuracy can be determined by comparing an analysis of a standard sample to the actual value (USEPA, 1996).  Project Watershed CNY/SOS conducted tests on standard solutions and makes adjustments as necessary. 

Precision

Precision is defined as the degree of agreement among repeated measurements of the same characteristic (USEPA, 1996). 

Completeness

According to the USEPA (1996), completeness refers to the comparison between the amount of data a program plans to collect and how much usable data were actually collected.  Project Watershed CNY/SOS estimates that approximately 90% of all measurements/tests are completed and the corresponding data usable.  Completeness is determined by comparing the number of valid measurements Project Watershed CNY/SOS volunteers actually collected versus the number of planned measurements.  Completeness takes into account incorrect analytical methods, equipment failure or breakage, adverse weather conditions, and safety issues.  All physical, chemical, and biological parameters will be measured/sampled during each monitoring event.  Student volunteers monitor their designated stream stretch twice a year; adult volunteers monitor bimonthly (April, June, August, October). 

Comparability

Comparability refers to the degree to which your program’s data can be compared to similar studies.  Project Watershed CNY/SOS ensures the comparability of its data by following protocols established in Mitchell and Stapp’s Field Manual for Water Quality Monitoring and by the Izaak Walton League of America Save Our Streams Program. 

Representativeness

Representativeness refers to the degree to which measurements are relevant to the true environmental condition.  Representativeness will be ensured by conducting all sampling and analytical procedures outlined in this QA/QC Project Plan and the Project Watershed CNY/SOS Study Design: SOPs.  Water samples will be:

· taken from the midsection of the stream within the main current;

· taken in a stream reach that describes the area of interest;

· taken in flowing waters and not in stagnant backwater areas;

· taken at the same sampling station/site; and

· analyzed, when appropriate, immediately at the sampling site (BOD and fecal coliform testing require additional analysis time in a lab).