Long-term Changes in Lamprey River Chemistry

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Long-term Changes in Lamprey River Chemistry

• William H. McDowell
• University of New Hampshire

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Lamprey River Hydrologic Observatory
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Research Questions

1. Are there long-term trends in Lamprey River
   chemistry driven by suburbanization?
2. Can variability in sub-basin surface water and
   groundwater chemistry be predicted by watershed
   attributes?
3. What drives long-term N balance in the Lamprey
   River watershed?

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Long-term Lamprey Sampling
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Nitrate Over Time in the Lamprey River
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Monthly Nitrate in the Lamprey River
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Dissolved Organic Carbon Over Time in the Lamprey
River
No significant trend with time
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Surface water nitrate is best predicted by human
population density
Lamprey Sub-basins
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Surface water nitrate is also related to urban
cover and agricultural land use
Lamprey, Ossipee and Oyster Sub-basins
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Dissolved Organic Matter is Related to Wetland
Cover
Lamprey, Ossipee and Oyster Sub-basins
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Nitrogen Inputs and Outputs from the Lamprey
River Watershed
Input 14.5 kg N ha-1 yr-1
Food
Retention 94 (or 13.7 kg N ha-1 yr-1) Stored or
lost to atmosphere?
3.1
Fertilizer
1.8
9.6
Rain and dry deposition
Output 0.8 kg N ha-1 yr-1