Specific Conductance
Specific Conductance
 Specific Conductance graph for Nequasset Watershed |
Specific conductance measures how easily water conducts electrical current. Because conductivity is affected by temperature, specific conductance adjusts results to what they would be at 25 degrees Celcius. Conductivity does not make this adjustment. It is a result of dissolved ions in the water. High conductivity results from more dissolved ions, and low conductivity results from fewer dissolved ions. Water acquires ions as it moves through the earth's crust; so the deeper the groundwater, the more ions it possesses. However, groundwater is not the only source of higher conductivity. Road salt, for example, is another source of higher conductivity. |
| In the Nequasset watershed, the overall conductivity is low due to the large input of surface water and the presence of fractured bedrock. Mineral weathering is also reduced in this watershed because water running through the fractures in the bedrock does not come into contact with the rock, and therefore weather, as much as it would in a more porous material. The specific conductance in this watershed is quite varied through the fall (mostly between 40-80 μS/cm) then trends toward a smaller range during the winter through the spring (mostly between 10-30 μS/cm). As the amount of snowmeltdecreases with the onset of spring, the conductivity is seen rebounding. The lower conductivity throughout the winter months can be attributed to a dilution of the water bodies due to precipitation and snow melt. However, during the fall the conductance at Wright Lane remains much higher than the other sites due to levels of groundwater which is the primary source of water due to the lack a large nearby wetland. The presence of dissolved ions in the groundwater increases its conductivity. The higher level of silica at Wright Lane demonstrates this fact. Though conductivity at Kohler Pond decreases similarly to the other sites in the winter, it spikes when other sites drop during precipitation events. During precipitation events most sites drop due to dilution of the water bodies whereas Kohler Pond stays high due to the runoff of road salts which are particularly influential here due to the sampling site's proximity to the road. The high conductivity at Meadow Road was unexpected because of the presence of wetlands and surface water inputs around it. Further investigation at the site may reveal an explanation. |
 Sampling site at outlet of Kohler Road Pond |
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