The Effects of Storms on Stream water Chemistry and the Seasonal Patterns of Ions in Tributaries of Lake Sunapee, New Hampshire

Storm events from summer 2012 and base flow events from 2011-2012 were studied to determine the changes in stream water chemistry between high and low flow events of the tributaries flowing into Lake Sunapee, New Hampshire. Additionally, water samples that were collected from 2011 to 2012 were also analyzed to determine seasonal trends in stream water chemistry. Many streams had discharge patterns during high flow events that increased, peaked, and then decreased, which is the expected pattern during storm events. There were some streams with little or no discharge (e.g. King Hill Lower) which is likely because it is a stream that receives much of the water from ground water as opposed to through storms. Both high flow and base flow water samples were analyzed for anions on the ion chromatograph (IC) and for cations on the inductively coupled plasma optical emission spectrometer (ICP). During high flow events, there was only a slight indication of the dilution effect at some streams, while other streams showed an increase in major cation (Ca2+, K+, Mg2+, Na+) and anion (Cl-, SO42-, NO3-) concentrations. Since only a few streams exhibited a dilution effect, it cannot be concluded that each time there is a storm, the ion concentrations in those streams will be diluted further suggesting that more research should be conducted on stream response to precipitation. Although historical data did not show patterns in ion concentrations amongst the seasons for individual streams, there were ions that were found in high concentrations in all streams. Seasonal characteristics showed that sodium (Na+) and calcium (Ca2+) were the major cations in all streams and were found in high concentrations throughout all seasons. Chloride (Cl-) was found to be the major anion in all streams and was found in great concentrations during the summer. Most streams had similar ion concentrations except for Herrick North and Herrick South which were always greater. While this study showed some streams respond more than others in ion concentrations, further study is required to fully determine the seasonal changes in each stream of ions, as well as how these streams respond to high flow events