Sources, fate, and transport of nitrogen and phosphorus in the Chesapeake Bay watershed: An empirical model

Ator, Scott W.; Brakebill, John W.; Blomquist, Joel D.

doi:10.3133/sir20115167

Cited by 57 publications

(145 citation statements)

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“…Further, groundwater-discharged nitrate removal was largely attributed to biotic uptake [Duff et al, 2008], which has been shown to be positively related to light availability [Peipoch et al, 2014]. The positive relationships between k and stream temperature are also consistent with the Chesapeake Bay total nitrogen SPARROW model estimates of k, which were lower at colder temperatures [Ator et al, 2011].…”

Section: /2015wr017753supporting

confidence: 72%

“…These estimates are within the range of model-derived estimates of k for permanent removal of total N ranging from 0.45 day 21 in small streams to 0.005 day 21 in the Mississippi River watershed [Alexander et al, 2000], and to 0.34 day 21 in small streams to 0.01 day 21 in larger streams in the Chesapeake Bay watershed [Ator et al, 2011].…”

Section: /2015wr017753supporting

confidence: 54%

“…While not explicitly quantified here, wastewater discharge has been shown to be an important contributor of N to urban streams during base flow conditions [Kaushal et al, 2011]. A Chesapeake Bay SPARROW model estimates that <1% of the total nitrogen load at the Smith Creek and Difficult Run sites and 7% at the Potomac River site was from point sources in 2002 [Ator et al, 2011]. Further, there are no known point source discharges to the study streams near the measurement locations, and point source discharges to streams in the Potomac River basin have been decreasing in recent years due to upgrades to waste water treatment plans [Woods et al, 2013].…”

Section: Groundwater-discharged Nitrate Loadsmentioning

confidence: 99%

“…There are multiple sources of N to these watersheds. For example, a Spatially Referenced Regression on Watershed attributes (SPAR-ROW) model estimated that of the total nitrogen load at the Potomac River in 2002, 7% was from point sources, 11% from urban sources, 51% from fertilizer application and fixation by crops, 13% from manure, and 18% from atmospheric deposition [Ator et al, 2011]. The same model estimated that <1% of the total nitrogen load at Smith Creek and Difficult Run was from point sources, and there are no known point sources discharging to the study streams near the measurement locations.…”

Section: Study Areas and Data Collectionmentioning

confidence: 99%

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Quantifying watershed‐scale groundwater loading and in‐stream fate of nitrate using high‐frequency water quality data

Miller

Tesoriero

Capel

et al. 2016

Water Resources Research

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We describe a new approach that couples hydrograph separation with high-frequency nitrate data to quantify time-variable groundwater and runoff loading of nitrate to streams, and the net in-stream fate of nitrate at the watershed scale. The approach was applied at three sites spanning gradients in watershed size and land use in the Chesapeake Bay watershed. Results indicate that 58-73% of the annual nitrate load to the streams was groundwater-discharged nitrate. Average annual first-order nitrate loss rate constants (k) were similar to those reported in both modeling and in-stream process-based studies, and were greater at the small streams (0.06 and 0.22 day 21 ) than at the large river (0.05 day 21 ), but 11% of the annual loads were retained/lost in the small streams, compared with 23% in the large river. Larger streambed area to water volume ratios in small streams results in greater loss rates, but shorter residence times in small streams result in a smaller fraction of nitrate loads being removed than in larger streams. A seasonal evaluation of k values suggests that nitrate was retained/lost at varying rates during the growing season. Consistent with previous studies, streamflow and nitrate concentrations were inversely related to k. This new approach for interpreting high-frequency nitrate data and the associated findings furthers our ability to understand, predict, and mitigate nitrate impacts on streams and receiving waters by providing insights into temporal nitrate dynamics that would be difficult to obtain using traditional field-based studies.

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Section: /2015wr017753supporting

confidence: 72%

Section: /2015wr017753supporting

confidence: 54%

Section: Groundwater-discharged Nitrate Loadsmentioning

confidence: 99%

Section: Study Areas and Data Collectionmentioning

confidence: 99%

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Quantifying watershed‐scale groundwater loading and in‐stream fate of nitrate using high‐frequency water quality data

Miller

Tesoriero

Capel

et al. 2016

Water Resources Research

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“…The dominant nonpoint source of N in many areas is agricultural fertilizer and manure; other nonpoint sources include atmospheric deposition and sewage disposal (Ator et al, 2011;Howarth et al, 1996). In sewered suburban areas, turfgrass fertilization may comprise the dominant source of N. Most N from nonpoint sources originates as organic forms or ammonium and is transformed to nitrate in the soil (Hallberg and Keeney, 1993) refers to the nitrate ion; in this paper, all laboratory analyses are for nitrate plus nitrite as elemental N, but the nitrite is assumed negligible, so the sum is simply referred to as nitrate).…”

Section: Introductionmentioning

confidence: 99%

Suburban Groundwater Quality as Influenced by Turfgrass and Septic Sources, Delmarva Peninsula, USA

Kasper

Denver²,

York

2015

J. Environ. Qual.

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Climate variability and extremes, interacting with nitrogen storage, amplify eutrophication risk

Lee

Shevliakova

Malyshev

et al. 2016

Geophysical Research Letters

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Despite 30 years of basin‐wide nutrient‐reduction efforts, severe hypoxia continues to be observed in the Chesapeake Bay. Here we demonstrate the critical influence of climate variability, interacting with accumulated nitrogen (N) over multidecades, on Susquehanna River dissolved nitrogen (DN) loads, known precursors of the hypoxia in the Bay. We used the process model LM3‐TAN (Terrestrial and Aquatic Nitrogen), which is capable of capturing both seasonal and decadal‐to‐century changes in vegetation‐soil‐river N storage, and produced nine scenarios of DN‐load distributions under different short‐term scenarios of climate variability and extremes. We illustrate that after 1 to 3 yearlong dry spells, the likelihood of exceeding a threshold DN load (56 kt yr−1) increases by 40 to 65% due to flushing of N accumulated throughout the dry spells and altered microbial processes. Our analyses suggest that possible future increases in climate variability/extremes—specifically, high precipitation occurring after multiyear dry spells—could likely lead to high DN‐load anomalies and hypoxia.

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Sources, fate, and transport of nitrogen and phosphorus in the Chesapeake Bay watershed: An empirical model

Cited by 57 publications

References 0 publications

Quantifying watershed‐scale groundwater loading and in‐stream fate of nitrate using high‐frequency water quality data

Quantifying watershed‐scale groundwater loading and in‐stream fate of nitrate using high‐frequency water quality data

Suburban Groundwater Quality as Influenced by Turfgrass and Septic Sources, Delmarva Peninsula, USA

Climate variability and extremes, interacting with nitrogen storage, amplify eutrophication risk

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