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March 30, 2026

Spatial Patterns in Dissolved Inorganic Nitrogen Along a Newly Constructed Stream Corridor in Loudoun County, Virginia

Ryan S. Nisay, Christian S. Shire

Abstract

Nutrient enrichment remains a persistent driver of water quality impairment throughout the Potomac River and Chesapeake Bay watershed, motivating localized stream restoration efforts aimed at reducing downstream nitrogen transport. This study characterized spatial patterns in dissolved inorganic nitrogen along a newly constructed stream corridor in Loudoun County, Virginia, during active restoration construction. Five monitoring sites spanning an upstream control, three construction zone locations, and a downstream reference were sampled twice daily over three weeks and analyzed for nitrate, nitrite, and ammonium using colorimetric methods. Nitrate concentrations did not decline systematically downstream; the two sites nearest active earthwork exhibited the highest mean values, exceeding the upstream control, while no statistically significant differences were detected across sites for any nitrogen species. These findings suggest that active construction may temporarily elevate nitrogen export, with implications for stream restoration project design and monitoring protocols.

Authors

  • Ryan S. Nisay
  • Christian S. Shire

Research Division, Loudoun Nature Conservation Project

Full Paper (PDF)

Self-published, Loudoun Nature Conservation Project

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