Water quality monitoring at Minute Man National Historical Park: Northeast Temperate Network 2014 summary report

Gawley, William; Dieffenbach, Fred

This report on the water quality of Minute Man National Historical Park (MIMA) includes data gathered by the Northeast Temperate Network (NETN) in the 2014 monitoring season and displays these results in graphic form, accompanied by a brief interpretation. The data address the NETN objective to detect change in the status of physical, chemical, or biological attributes of park freshwater bodies. The NETN Freshwater Monitoring Protocol calls for a total of three park streams to be sampled monthly from May through October at MIMA. Staff measured physical and in-situ water chemistry parameters each month and periodically collected water samples for analysis at the University of Maine’s Sawyer Environmental Chemistry Research Laboratory. Monthly sampling parameters included in-situ water quality measures (pH, specific conductance, temperature, dissolved oxygen, and turbidity), weather, stream flow (discharge), and stream stage. In May and August, water samples were obtained and analyzed for acid neutralizing capacity (ANC), color, nutrients, dissolved organic carbon (DOC), chloride, and sulfate. Most water quality parameters for the monitored streams were within state standards, and were generally within the ranges of the historic NETN monitoring data from MIMA. Exceptions were the high temperatures in July at Mill Brook and Elm Brook, and the low DO readings from Mill Brook (June and July) and the Concord River (July). Additionally, although there is no state standard for chloride, the values were very high and likely reflect runoff of road de-icing chemicals. ANC measurements showed that all streams had sufficient buffering to avoid severely depressed pH values from spring snowmelt and runoff that can contribute acidity and sediment to the stream water. Test results for TN and NO3 were moderately high in most 2014 samples. Results for NO2 were low at all sites. All ammonia (NH3) test results were below the method reporting limit of 0.08 mg/L. All total phosphorus results for 2014 were high and significantly above the EPA Region 14 criterion of 31.25µg/L. These results indicate that some nutrient enrichment is occurring in MIMA streams.

Water quality monitoring at Minute Man National Historical Park: Northeast Temperate Network 2014 summary report

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