A Pilot Study of Watershed Flow Using Stable Water Isotopes in Support of the Development of the Lamprey River Watershed (Southeast New Hampshire) as a Hydrologic Observatory
Abstract
The Lamprey River Watershed provides a suite of ecologic, geographic, geologic, and cultural characteristics that together provide an excellent opportunity to establish a convenient, unique, instructive, and informative natural laboratory. Researchers at the University of New Hampshire are establishing the Lamprey River Watershed, located in the seacoast region of New Hampshire, as a long term hydrologic observatory, where the instrumentation, data, and results from multi-disciplinary studies can be integrated to achieve greater understanding of the hydrologic system as a whole.One component of this proposed research is the establishment of a long term record of water isotope data. The results of a 1.5-year pilot study of stable water isotopes in the Headwaters of the Lamprey River Watershed (HLRW) are the focus of this presentation. In order to better understand groundwater flowpaths and residence times within the HLRW, we used stable water isotopes as natural tracers. For the period of June 2006 through October 2007, over 200 total water samples of groundwater, surface water, precipitation, and infiltration were collected and analyzed for stable hydrogen and oxygen isotopes. Based on analysis of isotopic and hydrometric data, the groundwater system is interpreted to be comprised of three distinct but interconnected reservoirs: a shallow groundwater reservoir which does not directly contribute to stream flow at the watershed outlet and has a mean residence time greater than 9 years; a near-surface groundwater reservoir, which is fed by the shallow system, flows through surface water bodies and wetlands with a mean residence time of approximately 1.5 months, and is the primary source of baseflow in the stream network; and a deep groundwater reservoir. The findings have significant implications for the interpretation of biogeochemical mass balance models of the Lamprey River Watershed and ongoing strontium isotope and trace element tracer studies. In a broader sense the results also advance the development of the Lamprey River Watershed as a long term hydrologic observatory.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.H53E1129F
- Keywords:
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- 1804 Catchment;
- 1829 Groundwater hydrology;
- 1832 Groundwater transport;
- 1879 Watershed