Factors driving nutrient trends in streams of the Chesapeake Bay watershed
| Autor: | Joel D. Blomquist, Scott W. Ator, James S. Webber, Jeffrey G. Chanat |
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| Rok vydání: | 2020 |
| Předmět: |
Environmental Engineering
Watershed Nitrogen STREAMS 010501 environmental sciences Management Monitoring Policy and Law 01 natural sciences Nutrient Effects of global warming Water Quality Waste Management and Disposal Nonpoint source pollution 0105 earth and related environmental sciences Water Science and Technology Phosphorus Nutrients 04 agricultural and veterinary sciences Pollution Bays Total maximum daily load 040103 agronomy & agriculture 0401 agriculture forestry and fisheries Environmental science Water quality Water resource management Bay |
| Zdroj: | Journal of Environmental Quality. 49:812-834 |
| ISSN: | 1537-2537 0047-2425 |
| Popis: | Despite decades of effort toward reducing nitrogen and phosphorus flux to Chesapeake Bay, water-quality and ecological responses in surface waters have been mixed. Recent research, however, provides useful insight into multiple factors complicating the understanding of nutrient trends in bay tributaries, which we review in this paper, as we approach a 2025 total maximum daily load (TMDL) management deadline. Improvements in water quality in many streams are attributable to management actions that reduced point sources and atmospheric nitrogen deposition and to changes in climate. Nutrient reductions expected from management actions, however, have not been fully realized in watershed streams. Nitrogen from urban nonpoint sources has declined, although water-quality responses to urbanization in individual streams vary depending on predevelopment land use. Evolving agriculture, the largest watershed source of nutrients, has likely contributed to local nutrient trends but has not affected substantial changes in flux to the bay. Changing average nitrogen yields from farmland underlain by carbonate rocks, however, may suggest future trends in other areas under similar management, climatic, or other influences, although drivers of these changes remain unclear. Regardless of upstream trends, phosphorus flux to the bay from its largest tributary has increased due to sediment infill in the Conowingo Reservoir. In general, recent research emphasizes the utility of input reductions over attempts to manage nutrient fate and transport at limiting nutrients in surface waters. Ongoing research opportunities include evaluating effects of climate change and conservation practices over time and space and developing tools to disentangle and evaluate multiple influences on regional water quality. |
| Databáze: | OpenAIRE |
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