Nitrate Hysteresis as a Tool for Revealing Storm‐Event Dynamics and Improving Water Quality Model Performance

Abstract Understanding the physics of nitrate contamination in surface and subsurface water is vital for mitigating downstream water quality impairment. Though high frequency sensor data have become readily available and computational models more accessible, the integration of these two methods for...

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Main Authors: Admin Husic, James F. Fox, Evan Clare, Tyler Mahoney, Amirreza Zarnaghsh
Format: Article
Language:English
Published: Wiley 2023-01-01
Series:Water Resources Research
Subjects:
Online Access:https://doi.org/10.1029/2022WR033180
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author Admin Husic
James F. Fox
Evan Clare
Tyler Mahoney
Amirreza Zarnaghsh
author_facet Admin Husic
James F. Fox
Evan Clare
Tyler Mahoney
Amirreza Zarnaghsh
author_sort Admin Husic
collection DOAJ
description Abstract Understanding the physics of nitrate contamination in surface and subsurface water is vital for mitigating downstream water quality impairment. Though high frequency sensor data have become readily available and computational models more accessible, the integration of these two methods for improved prediction is underdeveloped. The objective of this study was to utilize high‐frequency data to advance our understanding and model representation of nitrate transport for an agricultural karst spring in Kentucky, USA. We collected 2‐years of 15‐min nitrate and specific conductance data and analyzed source‐timing dynamics across dozens of events to develop a conceptual model for nitrate hysteresis in karst. Thereafter, we used the sensing data, specifically discharge‐concentration indices, to constrain modeled nitrate prediction bounds as well as the uncertainty of hydrologic and nitrogen processes, such as soil percolation and biogeochemical transformation. Observed nitrate hysteresis behavior at the spring was complex and included clockwise (n = 11), counterclockwise (n = 13), and figure‐eight (n = 10) shapes, which contrasts with surface systems that are often dominated by a single hysteresis shape. Sensing results highlight the importance of antecedent connectivity to nitrate‐rich storages in determining the timing of nitrate delivery to the spring. After integrating hysteresis analysis into our numerical model evaluation, simulated nitrate prediction bounds were reduced by 43 ± 12% and parameter uncertainty by 36 ± 20%. Taken together, this study suggests that discharge‐concentration indices derived from high‐frequency sensor data can be successfully integrated into numerical models to improve process representation and reduce modeled uncertainty.
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spelling doaj-art-e61e3b22276d48d4995c306358133b7b2025-08-20T03:27:05ZengWileyWater Resources Research0043-13971944-79732023-01-01591n/an/a10.1029/2022WR033180Nitrate Hysteresis as a Tool for Revealing Storm‐Event Dynamics and Improving Water Quality Model PerformanceAdmin Husic0James F. Fox1Evan Clare2Tyler Mahoney3Amirreza Zarnaghsh4Department of Civil, Environmental and Architectural Engineering University of Kansas Lawrence KS USADepartment of Civil Engineering University of Kentucky Lexington KS USADepartment of Civil Engineering University of Kentucky Lexington KS USADepartment of Civil and Environmental Engineering University of Louisville Louisville KY USADepartment of Civil, Environmental and Architectural Engineering University of Kansas Lawrence KS USAAbstract Understanding the physics of nitrate contamination in surface and subsurface water is vital for mitigating downstream water quality impairment. Though high frequency sensor data have become readily available and computational models more accessible, the integration of these two methods for improved prediction is underdeveloped. The objective of this study was to utilize high‐frequency data to advance our understanding and model representation of nitrate transport for an agricultural karst spring in Kentucky, USA. We collected 2‐years of 15‐min nitrate and specific conductance data and analyzed source‐timing dynamics across dozens of events to develop a conceptual model for nitrate hysteresis in karst. Thereafter, we used the sensing data, specifically discharge‐concentration indices, to constrain modeled nitrate prediction bounds as well as the uncertainty of hydrologic and nitrogen processes, such as soil percolation and biogeochemical transformation. Observed nitrate hysteresis behavior at the spring was complex and included clockwise (n = 11), counterclockwise (n = 13), and figure‐eight (n = 10) shapes, which contrasts with surface systems that are often dominated by a single hysteresis shape. Sensing results highlight the importance of antecedent connectivity to nitrate‐rich storages in determining the timing of nitrate delivery to the spring. After integrating hysteresis analysis into our numerical model evaluation, simulated nitrate prediction bounds were reduced by 43 ± 12% and parameter uncertainty by 36 ± 20%. Taken together, this study suggests that discharge‐concentration indices derived from high‐frequency sensor data can be successfully integrated into numerical models to improve process representation and reduce modeled uncertainty.https://doi.org/10.1029/2022WR033180hysteresissensorsuncertaintymodelingkarstnitrate
spellingShingle Admin Husic
James F. Fox
Evan Clare
Tyler Mahoney
Amirreza Zarnaghsh
Nitrate Hysteresis as a Tool for Revealing Storm‐Event Dynamics and Improving Water Quality Model Performance
Water Resources Research
hysteresis
sensors
uncertainty
modeling
karst
nitrate
title Nitrate Hysteresis as a Tool for Revealing Storm‐Event Dynamics and Improving Water Quality Model Performance
title_full Nitrate Hysteresis as a Tool for Revealing Storm‐Event Dynamics and Improving Water Quality Model Performance
title_fullStr Nitrate Hysteresis as a Tool for Revealing Storm‐Event Dynamics and Improving Water Quality Model Performance
title_full_unstemmed Nitrate Hysteresis as a Tool for Revealing Storm‐Event Dynamics and Improving Water Quality Model Performance
title_short Nitrate Hysteresis as a Tool for Revealing Storm‐Event Dynamics and Improving Water Quality Model Performance
title_sort nitrate hysteresis as a tool for revealing storm event dynamics and improving water quality model performance
topic hysteresis
sensors
uncertainty
modeling
karst
nitrate
url https://doi.org/10.1029/2022WR033180
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AT jamesffox nitratehysteresisasatoolforrevealingstormeventdynamicsandimprovingwaterqualitymodelperformance
AT evanclare nitratehysteresisasatoolforrevealingstormeventdynamicsandimprovingwaterqualitymodelperformance
AT tylermahoney nitratehysteresisasatoolforrevealingstormeventdynamicsandimprovingwaterqualitymodelperformance
AT amirrezazarnaghsh nitratehysteresisasatoolforrevealingstormeventdynamicsandimprovingwaterqualitymodelperformance