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 contaminated with mercury (at about 2ppm) and other metals, which are present in the sediment of Factory Pond, the site of a Fireworks factory. The Massachusetts DEP has posted the river with warnings of catch and release only.
Our major concern remains the extremely high concentrations of nitrogen measured at both the upstream and downstream sites along the river. Nitrogen concentrations fell in the fall of 2007 but have once again increased and the load for both sites has crept back up to 62 kg/day in 2008 and 64 kg/day in 2008.
Phosphorus levels often fell within the undetectable limit during the course of this study. Phosphorus levels at both sites had a tendency to drop off in the month of March.
Macroinvertebrate analyses at the two river sites indicate a continuing relationship between total discharge, biotic indices and species diversity. During periods of lower flow and/or changes 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. Due to high water levels during this year’s study, members of the hydropsychidae family occupied an overwhelming percentage of the total sample of 300 macroinvertebrates counted per each site.
Interestingly, the mathematical difference between the discharge at the Site A study site at Broadway St. and that at the Site B, Curtis Crossing study site had markedly decreased in eight years. The reasons for this remain unclear, however, increasing populations and building on either side of the river may be putting withdrawal demands on the river between these two sites.
- Continue monitoring for Phosphorus and Nitrogen levels in the 2010-2011 year at both study sites.
- Collect standing water data from Factory Pond in order to explore nitrogen concentrations here.
- Contact the EPA regarding rumors that Factory Pond will be dredged to remove what many believe are encapsulated heavy metals in the sediment of the pond.
- Investigate further the possible withdrawal of water between the upstream study site and the downstream study site by new construction and homes.
Hanson Middle School, Hanson, Massachusetts (2010). Hanson River Watch 2009-2010. In Watershed Access Lab Projects. Project 93.
Available at: http://vc.bridgew.edu/wal_projects/93
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