Development and Implementation of a Bayesian-based Aquifer Vulnerability Assessment in Florida

Arthur, J.K.; Wood, H. Alex R.; Baker, Alan E.; Cichon, James R.; Raines, Gary L.

doi:10.1007/s11053-007-9038-5

Cited by 92 publications

(61 citation statements)

References 19 publications

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“…To determine hydrogeologic predictors of variation among springs in excess air entrainment and recharge temperature, we characterized each spring by latitude, long-term mean discharge, and springshed hydrogeology as measured by aquifer vulnerability to surface contamination (Arthur et al, 2007). We collected discharge records for each spring from online databases of the United States Geological Survey National Water Information System (http: //waterdata.usgs.gov/nwis), Southwest Florida Water Management District (http://www.swfwmd.state.fl.us/data/), and the St. John's River Water Management District (http: //www.sjrwmd.com/toolsGISdata/index.html) where available, since these records were generally the most complete.…”

Section: Springshed Characterizationmentioning

confidence: 99%

“…We used the Floridan Aquifer Vulnerability Assessment (FAVA) as a metric of springshed hydrogeologic characteristics (Arthur et al, 2007). This measure quantifies the intrinsic contamination risk of the Upper Florida Aquifer (UFA) based on local hydrogeologic conditions such as aquifer chemistry, surface soil permeability, surface elevation, subsurface stratigraphy, presence of karst features (e.g.…”

Section: Springshed Characterizationmentioning

confidence: 99%

“…This measure quantifies the intrinsic contamination risk of the Upper Florida Aquifer (UFA) based on local hydrogeologic conditions such as aquifer chemistry, surface soil permeability, surface elevation, subsurface stratigraphy, presence of karst features (e.g. sinkholes) at the surface, thickness of a the intermediate aquifer system that regulates hydraulic confinement of the UFA, and the potentiometric head difference between the surface and UFA (Arthur et al, 2007). Based on these characteristics, regions of the UFA have been designated as "less vulnerable", "vulnerable", and "most vulnerable".…”

Section: Springshed Characterizationmentioning

confidence: 99%

“…Excess N 2 produced in such environments, after the last contact of a water parcel with the atmosphere, could certainly contribute to observed accumulation of N 2 in springs and groundwaters within the UFA. However, the signal of recent recharge in the UFA tends to be oxic, nitrate-rich water (Arthur et al, 2007), suggesting that reduced surface environments contribute minimally to inflow of excess N 2 . Moreover, the strong correlations among gaseous and isotopic signatures of denitrification might not be expected if surface environments with the potential for atmospheric exposure were the predominant location of NO (Fig.…”

Section: Uncertainty In Estimates Of Denitrificationmentioning

confidence: 99%

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Denitrification and inference of nitrogen sources in the karstic Floridan Aquifer

et al. 2012

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Abstract. Aquifer denitrification is among the most poorly constrained fluxes in global and regional nitrogen budgets. The few direct measurements of denitrification in groundwaters provide limited information about its spatial and temporal variability, particularly at the scale of whole aquifers. Uncertainty in estimates of denitrification may also lead to underestimates of its effect on isotopic signatures of inorganic N, and thereby confound the inference of N source from these data. In this study, our objectives are to quantify the magnitude and variability of denitrification in the Upper Floridan Aquifer (UFA) and evaluate its effect on N isotopic signatures at the regional scale. Using dual noble gas tracers (Ne, Ar) to generate physical predictions of N 2 gas concentrations for 112 observations from 61 UFA springs, we show that excess (i.e. denitrification-derived) N 2 is highly variable in space and inversely correlated with dissolved oxygen (O 2 ). Negative relationships between O 2 and δ 15 N NO3 across a larger dataset of 113 springs, well-constrained isotopic fractionation coefficients, and strong 15 N: 18 O covariation further support inferences of denitrification in this uniquely organic-matter-poor system. Despite relatively low average rates, denitrification accounted for 32 % of estimated aquifer N inputs across all sampled UFA springs. Back-calculations of source δ 15 N NO3 based on denitrification progression suggest that isotopically-enriched nitrate (NO − 3 ) in many springs of the UFA reflects groundwater denitrification rather than urban-or animal-derived inputs.

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Section: Springshed Characterizationmentioning

confidence: 99%

Section: Springshed Characterizationmentioning

confidence: 99%

Section: Springshed Characterizationmentioning

confidence: 99%

Section: Uncertainty In Estimates Of Denitrificationmentioning

confidence: 99%

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Denitrification and inference of nitrogen sources in the karstic Floridan Aquifer

et al. 2012

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“…In some cases, no distinction is made between specific vulnerability and risk assessment, with hazard types, distribution, loading, and transport all included at the risk-assessment stage (e.g., Focazio et al 2002). Without unambiguous and universally accepted definitions of vulnerability and risk in the assessment methods, this study follows the same terminology used in previous studies on groundwater vulnerability assessment using spatial statistical techniques (e.g., Arthur et al 2007;Sorichetta et al 2011). Hence, the term "groundwater vulnerability to nitrate contamination" will be used.…”

Section: Introductionmentioning

confidence: 99%

Groundwater vulnerability assessment: from overlay methods to statistical methods in the Lombardy Plain area

2017

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Riassunto: Le acque sotterranee sono tra le più importanti risorse di acqua potabile. A livello mondiale, gli acquiferi sono sottoposti ad una crescente minaccia di inquinamento legato all'urbanizzazione, allo sviluppo industriale, alle attività agricole ed alle imprese minerarie. Quindi sono ampiamente richieste azioni, strategie e soluzioni pratiche per proteggere le acque sotterranee da queste fonti antropiche. Lo strumento più utile, a supporto della pianificazione territoriale e protezione delle acque sotterranee dalla contaminazione, è rappresentato dalla valutazione della vulnerabilità degli acquiferi. Sono stati sviluppati diversi metodi per la valutazione della vulnerabilità degli acquiferi nel corso degli anni: metodi a zonazione omogenea o a pesi e punteggi, metodi statistici e metodi numerici. Tutti questi strumenti sono utili per sintetizzare informazioni idrogeologiche complesse in un unico documento, come le mappe di vulnerabilità, utilizzabili sia da tecnici, amministratori e politici, che da scienziati e cittadini. Sebbene non sia possibile identificare un approccio che possa essere il migliore in tutte le situazioni, il prodotto finale deve essere sempre scientificamente provato, significativo ed affidabile. Ciò nonostante, diversi metodi possono produrre risultati molto differenti in qualsiasi caso di studio. Perciò è necessario approfondire le ragioni di similitudini e differenze.Questo studio dimostra l'affidabilità e la versatilità di un metodo statistico-spaziale per la valutazione della vulnerabilità degli acquiferi alla contaminazione a scala regionale. Il caso di studio della pianura lombarda è particolarmente interessante per la sua lunga storia di monitoraggio quantitativo e qualitativo delle acque sotterranee, la disponibilità di dati idrogeologici e la combinata presenza di diverse sorgenti antropiche di contaminazione. Aggiornamenti recenti del Piano di Tutela delle Acque hanno sollevato la necessità di realizzare mappe di vulnerabilità degli acquiferi più versatili, affidabili e veritiere. Un confronto tra mappe di vulnerabilità degli acquiferi ottenute da approcci differenti e realizzati in un intervallo di tempo di diversi anni ha dimostrato l'importanza del continuo progresso scientifico, riconoscendo pregi e difetti di ciascuna ricerca.

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Development of a discrete‐continuum VDFST‐CFP numerical model for simulating seawater intrusion to a coastal karst aquifer with a conduit system

2017

Water Resources Research

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A hybrid discrete‐continuum numerical model, Variable‐Density Flow and Solute Transport—Conduit Flow Process (VDFST‐CFP), is developed to simulate seawater intrusion to a coastal karst aquifer with a conduit network. The Darcy‐Weisbach equation is applied to simulate the nonlaminar groundwater flow in the conduit system that is conceptualized as pipes, while the Darcy equation is used for laminar groundwater flow in the continuum porous medium. Density‐dependent groundwater flow with appropriate additional density terms in the conduit is analytically derived. The flow and transport equations are coupled, and numerically solved by the finite difference method with an implicit iteration procedure. Two synthetic benchmarks are developed to compare the VDFST‐CFP model results with other numerical models, such as the variable‐density SEAWAT, constant‐density continuum MODFLOW/MT3DMS, and constant‐density discrete‐continuum CFPv2/UMT3D models. The VDFST‐CFP model compares reasonably well with the other model results in both conduit and porous medium domains, and well describes water and salt exchange between the two systems. Under turbulent flow conditions within the conduit, the Darcy‐Weisbach equation calculates the flow rate more accurately without overestimation by the Darcy equation. Sensitivity analysis indicates that conduit diameter, friction factor, matrix hydraulic conductivity, and effective medium porosity are important parameters in the VDFST‐CFP model. The pros and cons of the VDFST‐CFP model are discussed, including the model assumptions and simplifications, limitations of the discrete‐continuum modeling method, and the convergence criteria. In general, the newly developed VDFST‐CFP model provides a new numerical modeling method for simulating seawater intrusion in a coastal karst aquifer with conduits.

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Development and Implementation of a Bayesian-based Aquifer Vulnerability Assessment in Florida

Cited by 92 publications

References 19 publications

Denitrification and inference of nitrogen sources in the karstic Floridan Aquifer

Denitrification and inference of nitrogen sources in the karstic Floridan Aquifer

Groundwater vulnerability assessment: from overlay methods to statistical methods in the Lombardy Plain area

Development of a discrete‐continuum VDFST‐CFP numerical model for simulating seawater intrusion to a coastal karst aquifer with a conduit system

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