Nitrogens path from dinner to streams: The role of sanitary infrastructure in the terrestrial flow field
Abstract
Food represents the single largest import of nitrogen to developed watersheds and societies task sanitary infrastructure with keeping it out of water bodies. To investigate the sources and transport of non-point source nitrogen (N): we evaluated compositional and structural attributes of 3,876 developed National Hydrography Dataset + (NHD+) catchments in the Research Triangle Region of North Carolina, continuously monitored N loading from five catchments along a development and sanitary infrastructure gradient, and grab sampled 27 catchments varying in landcover, sanitary infrastructure, geology, and topography. Our findings suggests that subsurface N, originating from wastewater, is abundant in the regions developed catchments and that the position of these sources within the terrestrial flow field governs loading and transport. Regionally 85% of NHD+ catchments had sanitary infrastructure within 200 ft of a stream. Estimated baseflow contributed a larger portion of total N loading than stormflow at the outlets of the continuously monitored catchments. Metrics of population, sanitary infrastructure hydrogeomorphic position, topography and agricultural landcover explained 78% of the variation in annual baseflow N loading across the grab sampled catchments. Isotopic analysis of NO3- indicated that wastewater was the dominant source. During baseflows, nitrogen concentrations generally increased with flow and the slope of this relationship was positively correlated to sanitary infrastructure topographic wetness. Managing baseflow loading will require regional efforts to support the N retention and removal capacity of the natural and built hydrologic network and local efforts to reduce N transport by considering the hydrogeomorphology of infrastructure and development.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.B43E..08D