Storm Event Nitrogen Fluxes

Understanding the Mechanisms Controlling Storm Event Nitrogen Fluxes from the Lamprey River Watershed Using Continuous in situ Sensors

Wilfred Wollheim, Assistant Professor of Aquatic Biogeochemistry, UNH (603.862.0812, and William McDowell, Professor of Environmental Science, UNH

Coastal New Hampshire is experiencing significant environmental problems associated with excess nitrogen. Specifically, the Great Bay Estuary was recently classified as nitrogen impaired by the U.S. Environmental Protection Agency due to both point and non-point sources. The largest non-point nitrogen pulses occur during storm flows, yet relatively little research has focused on understanding these pulses due to logistical difficulties in collecting regular samples throughout storm events.

These short-term pulses may provide a significant source of nitrogen to Great Bay without being fully accounted for. Recent technological advances in highly sensitive in situ nutrient sensors offer the potential to better understand nutrient dynamics across flow conditions. Researchers will deploy continuous in situ sensors at the Lamprey River USGS gauging station located five km upstream of Great Bay to monitor nitrogen and organic carbon fluxes across storms, seasons and years. They will then compare the results to identical measurements taken from samples in the headwaters of the Lamprey River and in Great Bay.

The results will be shared with local land use planners and resource managers to help them make more informed decisions about the nutrient dynamics within the Great Bay Estuary and reduce nitrogen levels in local and regional waterways.

N.H. EPSCoR also put together a video about Wollheim's NHSG-funded research: