Continuous monitoring and Bayesian estimation of nutrient and sediment loads from Illinois watersheds, for water years 2016–2020

Hodson, Timothy O.; Terrio, Paul J.; Peake, Colin S.; Fazio, David J.

doi:10.3133/sir20215092

Cited by 5 publications

(4 citation statements)

References 6 publications

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“…At Kankakee River at Davis, turbidity was measured in Formazin Nephelometric Units (FNU), with a YSI 6600 5‐parameter water‐quality sonde, and nitrate as nitrate plus nitrite in (mg/L as nitrogen), with a Satlantic Submersible Ultraviolet Nitrate Analyser (SUNA) V2‐5 mm path length nitrate monitor. At Green River near Geneseo, discharge was measured in cubic feet per second (cfs); turbidity was measured in Formazin Nephelometric Units (FNU), using two sets of sondes – YSI EXO2 multiparameter sonde and HACH Solitax, and nitrate (mg/L) as nitrate plus nitrite in (mg/L as nitrogen), with a HACH Nitratax plus sc 2 mm path length (Hodson et al, 2021). Lab and field testing of different ultraviolet (UV) spectrophotometer nitrate analyzers by the USGS Hydrologic Instrumentation Facility (HIF) showed good correlation to discrete samples, although there were deviations to the testing criteria and to the manufacturer's technical specifications (Snazelle, 2015).…”

Section: Methodsmentioning

confidence: 99%

Inferring drivers of nitrate and sediment event dynamics from hysteresis metrics for two large agricultural watersheds

Bolade,

Hansen

2023

Hydrological Processes

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Excess nitrate and sediment, mobilized by precipitation events and transported into surface waters, is a global water quality challenge. Recent advances in high‐frequency in situ water quality monitoring sensors have created opportunities to investigate constituent concentration dynamics during short‐term hydrological changes. In this study, we characterized the event‐scale variability of nitrate () and turbidity (a surrogate for sediment transport) in two large agricultural watersheds of the Upper Mississippi River Basin using hysteresis loop characteristics to determine sources and dominant transport mechanisms. We then applied factor analysis to detect variable groupings and thus determine controls on nitrate and sediment dynamics. We observed consistent counterclockwise hysteresis patterns between the two watersheds. This was indicative of distal contributions and/or late‐event mobilization and flushing, which was controlled by the characteristics of the event hydrology (such as, event duration and magnitude of event discharge). However, turbidity hysteresis loops indicated different sediment delivery behaviours between the two watersheds. The smaller watershed with more diverse land use demonstrated consistent clockwise hysteresis patterns indicating early event flushing or rapidly responding pathways. The time lag between turbidity and discharge peaks was identified as a driver of hysteresis magnitude for the smaller site. In contrast, the larger and more agricultural watershed showed variability between dilution versus flushing as well as delivery pathways between events. The hysteresis magnitude was driven by the event peak discharge and discharge range demonstrating an increase in stream power with scale influenced sediment dynamics at the larger site that switched behaviour. This result is critical for watershed water quality management, especially in the context of a changing climate and further underscores the utility of high‐frequency sensors monitoring data to offer deep insights into hydrological processes controls on contaminant transport and delivery.

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Section: Methodsmentioning

confidence: 99%

Inferring drivers of nitrate and sediment event dynamics from hysteresis metrics for two large agricultural watersheds

Bolade,

Hansen

2023

Hydrological Processes

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“…For most sites and constituents approximately 300 concentration values were obtained, but the number varied due to differences in sampling frequency and the first year of concentration measurement, which ranged from 1977 to 1985. The number of samples used for each annual load estimate is reported in Hodson (2021).…”

Section: Methodsmentioning

confidence: 99%

“…The lag‐1 autocorrelation coefficients for all models were set to 0.9. The resulting annual load estimates and associated uncertainty estimate statistics are available as a separate data release (Hodson 2021).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Spatial and Temporal Variations in Phosphorus Loads in the Illinois River Basin, Illinois USA

McIsaac

Hodson

Markus

et al. 2022

J American Water Resour Assoc

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Total phosphorus (TP) loads in many rivers in the north‐central United States have increased, including the Illinois River at Valley City, Illinois, USA, which increased 39% from the periods 1989–1996 to 2015–2019 despite efforts to reduce loads from point and nonpoint sources. Here, we quantify long‐term variations in phosphorus (P) loads in the Illinois River and its tributaries and identify factors that may be causing the variations. We calculated river loads of dissolved (DP) and particulate P (PP), total and volatile suspended solids (TSS and VSS), and other potentially related constituents at 41 locations. DP loads generally increased and PP and TSS loads generally decreased from 1989–1996 to 2015–2019. During 1989–1996, P accumulated in the lower basin between Marseilles and Valley City (excluding monitored tributaries). This portion of the basin is very flat and accumulates sediment. During 2015–2019, this section shifted from being a net sink to being a net source of P, accounting for 78% of the increased TP load at Valley City. We present evidence supporting several mechanisms that could have caused this shift: increased DP and chloride loads, reduced sulfate and nitrate concentrations influencing ionic strength and redox potential in the sediments, and increased VSS loads at Valley City possibly indicating greater algal production and contributing to hypoxia in lower river sediments. Additional research is needed to quantify the relative importance of these mechanisms.

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Continuous monitoring and Bayesian estimation of nutrient and sediment loads from Illinois watersheds, for water years 2016–2020

Cited by 5 publications

References 6 publications

Inferring drivers of nitrate and sediment event dynamics from hysteresis metrics for two large agricultural watersheds

Inferring drivers of nitrate and sediment event dynamics from hysteresis metrics for two large agricultural watersheds

Spatial and Temporal Variations in Phosphorus Loads in the Illinois River Basin, Illinois USA

Verification of multiple phosphorus analyzers for use in surface-water applications

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