Nitrogen inventories in the Nooksack-Fraser Transboundary Watershed
Citation:
Lin, J., J. Compton, J. Baron, C. Clark, D. Schwede, S. Bittman, D. Hooper, B. Carey, P. Homann, H. Winter, P. Kiffney, N. Embertson, H. MacKay, R. Black, AND G. Bahr. Nitrogen inventories in the Nooksack-Fraser Transboundary Watershed. ICRW, Sherpherdstown, WV, July 16 - 20, 2018.
Impact/Purpose:
The Nooksack-Fraser transboundary area is home to communities with a strong base in farming, fisheries and outdoor recreation. A goal of the Nooksack-Fraser Transboundary Nitrogen (NFT-N) project is to determine the sources and fates of N in the watershed using data on energy use, transportation, fertilization, wastewater treatment plants, animal feeding operations, wildlife and more. Water quality issues impact parts of this area, where sewage effluent and animal waste are potential sources of both fecal coliform bacteria (FCB) and nitrogen (N) in the environment. Nitrogen loading can lead to eutrophication in coastal areas, and nitrate contamination of groundwater. This project brings together stakeholders, agencies, and scientists on both sides of the international boarder to achieve a first characterization of N inventories and fluxes across the transboundary watershed. This work represents a collaborative effort between a large team of stakeholders who are assembling a preliminary N budget for the Nooksack Basin, to inform policy and decisions in the basin. The abstract will be submitted to the Interagency Conference on Research in Watersheds, as part of a session on water quality in the Nooksack Basin.
Description:
Excessive nitrogen (N) loading can lead to eutrophication in coastal and fresh waters, air quality issues, and nitrate contamination of groundwater. The Nooksack-Fraser Transboundary-Nitrogen (NFT-N) project was developed to explore ways to work with a community to balance the beneficial and harmful aspects of nitrogen management. The NFT area (2639 km2) is home to communities with a strong base in farming, fisheries and outdoor recreation. Our first goal was to determine the sources and fates of N in the watershed in year 2014 using data on energy use, transportation, fertilization, wastewater treatment plants, livestock operations, wildlife and more. This project brought together Tribes, stakeholders, agencies, and scientists on from the US and Canada to characterize this transboundary N inventory. A comprehensive N assessment can benefit decision-making by providing key information on sources, sinks and effects. This effort builds upon an existing Canadian N inventory for the Lower Fraser Valley, and currently is focusing on the N sources on the US side. First, we estimated N needed for crops using local data collected in 2014, and constructed scenarios using various agricultural practices, fertilization rates, and management intensities. Preliminary results show that, in order to meet the plants demand on the US side of the watershed, about 2947-3526 metric tons (MT) of N needs to be applied. Because approximately 65% of applied manure N is available to crops after denitrification, mineralization, and volatilization loss, using manure as a fertilizer would require 5937-7103 MT manure N. The combined septic and sewage input of N ranges between 71 and 84 MT per year, while atmospheric deposition contributes 527 MT N per year. Our results demonstrate the importance of N inputs from agriculture. Future efforts will include updated agricultural data and Canadian budget information, and improved understanding of N fate and transport in ground and surface water in order to examine the impacts of N policy and management across the boundary (US-Canada), and to develop sustainable N management plans in the region.