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Whitman-Hanson Regional High School, Whitman, Massachusetts


Laurie Bianchi


Whitman-Hanson Regional High School RiverNet Club 2005


The Indian Head River is a tributary of the North River which is part of the South Coastal Basin. The Drinkwater becomes the Indian Head River below Factory Pond on the Hanson/Hanover line. Upstream there are a number of businesses but from Factory Pond downstream, much of the river has a forested riparian zone. The Indian Head River flows through the towns of Hanson, Hanover, and Pembroke. Between the two study sites there is some white water including several small waterfalls.

This is the fourth year that Whitman-Hanson Regional Schools have investigated the Indian Head River. The High School studied the river during 2004-2005 and Hanson Middle School did the research the previous school years. There is some variation in water quality throughout the years of the study, which may be attributable to weather and flow patterns rather than any change in human activities. It appears that the water quality may have improved slightly since 2001 at the downstream site B. While pH remained fairly stable, dissolved oxygen increased to a very healthy level in 2003 and 2004. Site B appears to have better water quality than upstream at Site A, which flows out of Factory Pond. Curtis Crossing (Site B) is immediately downstream from a dam and waterfall with an additional drop in elevation below the bridge giving rise to riffle environments. The small waterfalls and rapids between Site A and B, may contribute to the increased dissolved oxygen levels.

Fecal coliform was low at both sites A and B although higher in a sampling location upstream in Rockland. All four locations tested showed no evidence of bacterial pollution. The macroinvertebrate analysis tested very good (3.12) at Site B yet there was a serious lack of diversity. Only four different families were captured and 95% of them were Tricoptera with a tolerance value of three. At Site A, there was more diversity with nine families. However, the family biotic index at Site A was fairly poor (5.9) and the dominant macroinvertebrate was fingernail clams which have a fairly high tolerance to pollution (seven). The 2004 macroinvertebrate data indicated the worst water quality in four years at the Winter Street site A, though the problem appears to be related to the substrate rather than the water. Dissolved oxygen was high in both locations and though pH varied slightly over four years, there was no indication of acid precipitation impacts. Although nitrogen-nitrate loads were higher than some past readings, they were much lower than in September, 2003 and February, 2004. The nitrogen:phosphorus ratio was 638:1 at Site A and 210:1 at Site B. Phosphorus was below detectable limits in both locations and is the limiting nutrient. Therefore the effect of the excess nitrogen should be negligible.

The Indian Head River appears relatively clean according to the data compiled over the last four years. Each water chemistry parameter tested was within the accepted range for Class B waters. The only problem noted in past years was the high nitrogen and nitrates in the system. The September 2004 readings were not excessive. Much of the nitrogen load is expected to be from local runoff and upstream which is more industrialized. There are businesses along the river in Hanover and Rockland above Factory Pond. Another source could be ducks that inhabit Factory Pond and Wampatuck Pond. People feed the ducks and they tend to stay throughout the winter. Fecal coliform results, however, do not support either hypothesis that the ducks or septic systems are the source of the high nitrates. Another possibility which has been suggested in the past is related to the decomposition of organic material. To further determine the sources of the nitrates, water samples should be collected at more locations and at different times of the year.

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Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.


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