Hanson Middle School, Hanson, Massachusetts
The Indian Head River is part of the large and complex system of streams and rivers, which contribute to the South Coastal Plain Watershed. A portion of the river forms the border to the Town of Hanson from where it flows into the main stem of the North River. Further upstream, the river is called the Drinkwater which itself drains into Factory Pond directly upstream of our study site A.
Historically the Indian Head, its headwaters and tributaries provided an important fishery for alewives, shad and rainbow smelt. However, the river suffered much the same as other river systems in Massachusetts and fish runs were diverted and dammed for agricultural and industrial purposes. Today, fish that are caught in the river are most likely contaminated with mercury and other metals, which are present in the sediment of Factory Pond, the site of a Fireworks factory.
This marks our third year of monitoring water quality indicators at two sites along the river. A third site on the Indian Head Brook was identified and was added this year. Data were collected on discharge, phosphorus and nitrogen concentrations. The Indian Head Brook drains from two ponds in Hanson and passes hydrologically through several small cranberry bogs.
Our major concern remains the extremely high concentrations of nitrogen measured at both the upstream and downstream sites along the river. Nitrogen concentrations peaked this year in February at 120 kg per liter. Originally, it was postulated that such high nitrogen concentrations pointed to septic infiltration. However, consistently low coliform counts (10, 20 and 40 colonies per 100 ml) do not appear to confirm this hypothesis.
Phosphorus levels often fell within the undetectable limit during the three year study. This year we were able to profile phosphorus levels at all three sites and showed that these drop dramatically during the month of March. We were also able to profile a similar drop – off of nitrogen concentrations at Site C while phosphorus concentrations here remained fairly constant.
Macroinvertebrate analyses at the two river sites indicate a relationship between total discharge, biotic indices and species diversity. During periods of lower flow and/or changers in substrate, populations of caddisfly larvae (Trichoptera) either drop out completely or become quite low. Due to their feeding strategies, these insect larvae may migrate to other areas. When discharge is low, other larvae, such as riffle beetles replace caddisfly larvae as the dominant species. Biotic indices also appear to fall when total discharge increases.
- Continue monitoring for Phosphorus and Nitrogen levels in the 2004/2005 school year at all three study sites.
- Collect standing water data from Factory Pond in order to explore nitrogen concentrations here.
- Design an experiment, which illustrates the rise and fall of nitrogen concentrations with decay of leaf litter.
Hanson Middle School, Hanson, Massachusetts (2004). Hanson Riverwater III: Indian Head River Study Year 3. In Watershed Access Lab Projects. Project 9.
Available at: http://vc.bridgew.edu/wal_projects/9
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