Bridgewater State University Virtual Commons - Bridgewater State University Watershed Access Lab Projects Watershed Access Lab 2005 The aT unton River's Last Major Tributary: Chemical Analysis of a Freshwater Dam System in the Upper Assonet River Recommended Citation Bridgewater-Raynham Regional High School, Bridgewater, Massachusetts (2005). The Taunton River's Last Major Tributary: Chemical Analysis of a Freshwater Dam System in the Upper Assonet River. In Watershed Access Lab Projects. Project 38. Available at: http://vc.bridgew.edu/wal_projects/38 This item is available as part of Virtual Commons, the open-access institutional repository of Bridgewater State University, Bridgewater, Massachusetts. The Bridgewater-Raynham Watershed Team (BRWT) Presents: The Taunton River's Last Major Tributary Chemical Analysis of Water in a Freshwater Dam System in the Upper Assonet River Fall 2005 Purpose of the Study • To study how a dam system in the upper Assonet River effects the chemical and nutrient levels downstream. • To prepare the Science Olympiad Team for the Freshwater Ecology section of their December 22nd meet at Bridgewater Raynham regional High School. • Figures will help students complete the eagle scout communication merit badge. • To increase stewardship and knowledge of the Taunton River Watershed (TRW) across Southeastern Massachusetts. The Taunton Watershed Basin (southern portion pictured) • Basin for 38 towns. • 221 lakes and ponds • 173 canoeable river miles • Home to the 16,800 acre Hocomock Swamp • 29 species of fish (brook trout included) • 114 species of birds • Source: http://www.trwaonline.org/ Location of Study * Weather and Site Conditions • Cloudy with some precipitation. • Cool Air Temperature (45oF) • Deciduous Trees dominate the landscape • Dark Water (leaves release dark acids) • Relatively Shallow Pond Sample Locations * * Pond and Dam System Spillway Hydrolab Data • Probes for hourly readings. • Graphical Analysis of Temperature,pH, Dissolved Oxygen (DO), and Specific Conductivity. Temperature vs.Time 10.6 10.4 10.2 10 Temperature(oC) 9.8 Forge Pond (Upstream) Mill Pond 9.6 (Downstream) 9.4 0:00:00 1:00:00 2:00:00 3:00:00 4:00:00 5:00:00 6:00:00 7:00:00 8:00:00 9:00:00 17:00:00 18:00:00 19:00:00 20:00:00 21:00:00 22:00:00 23:00:00 10:00:00 11:00:00 12:00:00 13:00:00 14:00:00 15:00:00 16:00:00 Time (HHMMSS) DO vs. Time 10 9 8 7 DO (mg/L)DO 6 Forge Pond (Upstream) 5 Mill Pond (Downstream) 4 1:00:00 3:00:00 5:00:00 7:00:00 9:00:00 17:00:00 19:00:00 21:00:00 23:00:00 11:00:00 13:00:00 15:00:00 Time (HHMMSS) DO Saturation (%) 100 90 80 70 60 DO SaturationDO (%) 50 Forge Pond (Upstream) Mill Pond (Downstream) 40 1:00:00 3:00:00 5:00:00 7:00:00 9:00:00 17:00:00 19:00:00 21:00:00 23:00:00 11:00:00 13:00:00 15:00:00 Time (HHMMSS) pH vs. Time 7 6.5 6 5.5 5 pH Units pH 4.5 Forge Pond (Upstream) 4 Mill Pond (Downstream) 3.5 3 1:00:00 3:00:00 5:00:00 7:00:00 9:00:00 17:00:00 19:00:00 21:00:00 23:00:00 11:00:00 13:00:00 15:00:00 Time (HHMMSS) Specific Conductivity (mS/cm) 0.105 0.1 0.095 0.09 0.085 0.08 SpecificConducivity (mS/cm) Forge Pond (Upstream) 0.075 Mill Pond (Downstream) 0.07 1:00:00 3:00:00 5:00:00 7:00:00 9:00:00 17:00:00 19:00:00 21:00:00 23:00:00 11:00:00 13:00:00 15:00:00 Time (HHMMSS) More Dissolved Substances in Mill Pond??? Sigma Data • Hourly water samples collected in bottles. • Analyzed at the Bridgewater State College Watershed Access Lab by Kim McCoy. • Larger amounts of phosphate and nitrate downstream. • Rainfall and storm events effect nutrient availability. Discussion and Conclusions • Dam systems can effect water temperature. • The dams changed the habitat by created pools and larger pond surface area. • DO levels were higher after the dam. • DO levels were higher in slightly warmer water. • DO effects the water pH by pushing other dissolved gasses out. • Specific conductivity is effect by narrow stream beds. Future Studies • Include data from the third dam. • Historically, the Assonet River was known for its trout. Then the dams were built. • Check seasonal variation (vegetation & evaporation) • Measure flow, discharge, and nutrient loading from the spillway. • Measure DO in the turbulent spillway. Thank you to… • Dr. Curry for his insight during the site visit. • Kim McCoy for her help with the equipment and data. Bridgewater-Raynham Watershed Team • Mark Madonna • Ray Seekell • Ann-Marie Illsey • Sehrish Abid • Laurie Soderbom • Kara Son • Mr. Levesque .