Dighton-Rehoboth Regional High School, Dighton, Massachusetts
Dighton-Rehoboth Regional High School Environmental Science Class
Can significant differences in Discharge and Nutrient concentration & load be determined or inferred for the Palmer River? Students studied 2 sites. These were located at Wilmarth Bridge Road (just off of Route 44) and at Reed Street (further south & downstream). Between the 2 sites are a few farms as well as a golf course. It is possible that runoff from these 2 sources has influenced the amount of phosphates &/or nitrates found in the Palmer River. Most Primary & Secondary habitat characteristics were the same for both sites; though Reed Street exhibited more variations
Students collected data on dissolved oxygen, temperature, pH, and nutrients. Temperature fluctuations were normal for the time frame investigated. A somewhat basic pH was found at the Wilmarth Bridge Road location, indicating either unknown contributors to alkalinity or the underlying geology of the parent rock material that the River weathers. Dissolved oxygen was higher at Reed Street, as would be expected due to aeration as water passed over the dam (at the Shad Factory Pond) and hit rocks. Both sites showed a gradual increase in DO throughout the day most likely caused by photosynthesis of aquatic vegetation.
Discharge increased from the Wilmarth Bridge Road to Reed Street as expected. Reactive phosphorus concentration was at or below detection limit for all samples. The concentration for nitrogen/nitrate was within normal range but always higher at Reed Street. Nitrate load was significantly higher at Reed Street, at a measured level of 191 Kg/day. Students concluded that the data lent support of their hypothesis that runoff from the 2 locations was altering nutrient load; though it did not establish a causal relationship.
Dighton-Rehoboth Regional High School, Dighton, Massachusetts (2007). Palmer River Water Discharge and Nutrient Study. In Watershed Access Lab Projects. Project 85.
Available at: http://vc.bridgew.edu/wal_projects/85
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