Point sources and agricultural practices control spatial-temporal patterns of orthophosphate in tributaries to Chesapeake Bay

Fanelli, Rosemary M.; Blomquist, Joel D.; Hirsch, Robert M.

doi:10.1016/j.scitotenv.2018.10.062

Cited by 37 publications

(42 citation statements)

References 72 publications

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“…Upward trends in dissolved reactive P loads from the Choptank watershed (Fig. 1, Table 1) and in other streams in the Delmarva Peninsula (Fanelli et al, 2019) confirm the persistence of P management concerns in the Atlantic Coastal Plain of the Chesapeake Bay watershed. Historically, there has been relatively limited monitoring of the Delmarva's riverine systems.…”

Section: The Delmarva Peninsulamentioning

confidence: 61%

“…Trends in water quality from USGS riverine monitoring sites on the Delmarva Peninsula and southeastern Pennsylvania provide compelling evidence of the conditions under which P loadings have been increasing over the past decade. Two of these monitoring sites (Choptank and Conestoga) have a significant catchment area in agriculture (41 and 28%, respectively) and export the second‐ and eighth‐largest dissolved reactive P yields in the monitoring network (Fanelli et al, 2019). Both the Choptank and Conestoga Rivers have increasing total P and dissolved reactive P (an estimate of inorganic P that is not associated with sediments) trends over the most recent 10‐yr period, with dissolved reactive P representing over half the total P load at Conestoga (Table 2).…”

Section: Mixed Progress At the Tmdl Midpointmentioning

confidence: 99%

“…These patterns are widespread across these two regions. Large dissolved reactive P exports are observed from Pequea Creek, Swatara Creek, and West Conewago Creek in southeastern Pennsylvania, as well as Marshyhope and Tuckahoe Creeks in the Delmarva Peninsula (Fanelli et al, 2019). …”

Section: Mixed Progress At the Tmdl Midpointmentioning

confidence: 99%

“…These concerns were confirmed by monitoring runoff from field soils (Staver and Brinsfield, 2001) and ditch drainage (Kleinman et al, 2007), the latter documenting loads greater than 20 kg ha −1 , with more than 90% of the P traveling through shallow groundwater to the region's open drainage ditches. Indeed, increasing dissolved P trends are even evident in low flows (e.g., fifth percentile flows) in some of the Chesapeake Bay's agricultural watersheds (Fanelli et al, 2019). Recognizing the unique nutrient management and P transport conditions of flat, intensively drained landscapes is key to advancing mitigation strategies as reflected by revision of Maryland's Phosphorus Management Tool (Shober et al, 2017).…”

Section: The Delmarva Peninsulamentioning

confidence: 99%

“…Equating mitigation activities to water quality improvement presents many challenges, from the complexity of accounting to scaling fate‐and‐transport processes to differentiating between the impacts of various forms of P. While all seven jurisdictions working on the restoration, except Pennsylvania, met the midpoint goals for implementing agricultural P mitigation practices in 2017, water quality improvements have been especially lacking in agricultural watersheds (Moyer and Blomquist, 2017; Fanelli et al, 2019). Furthermore, based on the version of the Chesapeake Bay Watershed Model used at the time of the 2017 TMDL midpoint (Phase 5.3.2), the six Chesapeake Bay watershed states will need to achieve an additional 0.46 million kg of P reductions per year from agriculture to meet the TMDL goals for 2025 (Chesapeake Bay Program, 2018b).…”

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confidence: 99%

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Phosphorus and the Chesapeake Bay: Lingering Issues and Emerging Concerns for Agriculture

Kleinman

Fanelli

Hirsch³

et al. 2019

J of Env Quality

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Hennig Brandt's discovery of phosphorus (P) occurred during the early European colonization of the Chesapeake Bay region. Today, P, an essential nutrient on land and water alike, is one of the principal threats to the health of the bay. Despite widespread implementation of best management practices across the Chesapeake Bay watershed following the implementation in 2010 of a total maximum daily load (TMDL) to improve the health of the bay, P load reductions across the bay's 166,000‐km2 watershed have been uneven, and dissolved P loads have increased in a number of the bay's tributaries. As the midpoint of the 15‐yr TMDL process has now passed, some of the more stubborn sources of P must now be tackled. For nonpoint agricultural sources, strategies that not only address particulate P but also mitigate dissolved P losses are essential. Lingering concerns include legacy P stored in soils and reservoir sediments, mitigation of P in artificial drainage and stormwater from hotspots and converted farmland, manure management and animal heavy use areas, and critical source areas of P in agricultural landscapes. While opportunities exist to curtail transport of all forms of P, greater attention is required toward adapting P management to new hydrologic regimes and transport pathways imposed by climate change. Core Ideas At the midpoint of the Chesapeake TMDL, dissolved P is increasing in some tributaries. Lingering concerns include legacy P, artificial drainage, animal heavy use areas. Extreme events represent an acute risk to water quality.

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Section: The Delmarva Peninsulamentioning

confidence: 61%

Section: Mixed Progress At the Tmdl Midpointmentioning

confidence: 99%

Section: Mixed Progress At the Tmdl Midpointmentioning

confidence: 99%

Section: The Delmarva Peninsulamentioning

confidence: 99%

mentioning

confidence: 99%

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Phosphorus and the Chesapeake Bay: Lingering Issues and Emerging Concerns for Agriculture

Kleinman

Fanelli

Hirsch³

et al. 2019

J of Env Quality

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Factors driving nutrient trends in streams of the Chesapeake Bay watershed

Ator¹,

Blomquist²,

Webber³

et al. 2020

J of Env Quality

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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 waterquality 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.

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Sediment phosphorus buffering in streams at baseflow: A meta‐analysis

et al. 2021

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Phosphorus (P) pollution of surface waters remains a challenge for protecting and improving water quality. Central to the challenge is understanding what regulates P concentrations in streams. This quantitative review synthesizes the literature on a major control of P concentrations in streams at baseflow-the sediment P bufferto better understand streamwater-sediment P interactions. We conducted a global meta-analysis of sediment equilibrium phosphate concentrations at net zero sorption (EPC 0), which is the dissolved reactive P (DRP) concentration toward which sediments buffer solution DRP. Our analysis of 45 studies and >900 paired observations of DRP and EPC 0 showed that sediments often have potential to remove or release P to the streamwater (83% of observations), meaning that "equilibrium" between sediment and streamwater is rare. This potential for P exchange is moderated by sediment and stream characteristics, including sorption affinity, stream pH, exchangeable P concentration, and particle sizes. The potential for sediments to modify streamwater DRP concentrations is often not realized owing to other factors (e.g., hydrologic interactions). Sediment surface chemistry, hyporheic exchange, and biota can also influence the potential exchange of P between sediments and the streamwater. Methodological choices significantly influenced EPC 0 determination and thus the estimated potential for P exchange; we therefore discuss how to measure and report EPC 0 to best suit research objectives and aid in interstudy comparison. Our results enhance understanding of the sediment P buffer and inform how EPC 0 can be effectively applied to improve management of aquatic P pollution and eutrophication.

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Point sources and agricultural practices control spatial-temporal patterns of orthophosphate in tributaries to Chesapeake Bay

Cited by 37 publications

References 72 publications

Phosphorus and the Chesapeake Bay: Lingering Issues and Emerging Concerns for Agriculture

Phosphorus and the Chesapeake Bay: Lingering Issues and Emerging Concerns for Agriculture

Factors driving nutrient trends in streams of the Chesapeake Bay watershed

Sediment phosphorus buffering in streams at baseflow: A meta‐analysis

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