'A tale of two cities': Nitrogen inventories in the Nooksack-Fraser Transboundary Watershed
Abstract
Spanning the border of U.S. and Canada, the Nooksack-Fraser transboundary area (2639 km2) is home to the communities of Lynden, Washington, and Abbotsford, British Columbia, with a strong base in farming, fisheries and outdoor recreation. Balancing these uses is a key issue in the area, where nitrogen (N) loading contributes to coastal eutrophication and prolonged contamination of groundwater. The Nooksack-Fraser Transboundary Nitrogen (NFT-N) project had an initial goal of creating a N budget using data on energy use, transportation, fertilization, wastewater treatment, livestock operations, and fisheries.
Using local data, we estimated that livestock feed and fertilizer import were the two largest N input sources to the U.S. part of the watershed, averaging 3472 and 1131 metric tons (MT) N yr-1, respectively. Atmospheric deposition was the third largest source of N to the watershed, averaging 527 MT N yr-1. The import of human and pet food added 655 MT N per year to the watershed. The returns of adult salmon brought in 6 MT N yr-1 to the watershed. N loss through volatilization of manure averaged 2035 MT N yr-1, and denitrification losses were approximately 204 MT N yr-1. N fluxes in surface and ground water will be estimated using load simulation and mass balance approaches. Preliminary results for the U.S. side demonstrate the importance of N inputs from agriculture sector, indicating that careful management of agricultural fertilizers and manures is key to improving water quality. Results will be refined by integrating with an existing Canadian N budget to achieve a complete budget for the watershed, and used to understand connections between inputs and N fates in ground and surface water. The budget will be used as a foundation to develop an ecosystem model for management scenario simulation, using the Visualizing Ecosystem Land Management Assessments (VELMA) model tool to support future efforts in developing sustainable N management plans in the region.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMGC23H1302L
- Keywords:
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- 0402 Agricultural systems;
- BIOGEOSCIENCESDE: 0470 Nutrients and nutrient cycling;
- BIOGEOSCIENCESDE: 1615 Biogeochemical cycles;
- processes;
- and modeling;
- GLOBAL CHANGEDE: 1630 Impacts of global change;
- GLOBAL CHANGE