LUMPED: a Visual Basic code of lumped-parameter models for mean residence time analyses of groundwater systems

Ozyurt, N. Nur; Bayarı, C. Serdar

doi:10.1016/s0098-3004(02)00075-4

Cited by 35 publications

(14 citation statements)

References 15 publications

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“…Models in LUMPEDUS are based on USLP model equations derived by Nir (1973) and Niemi (1990a) and it can be run in both SS and US modes. The SS results of LUMPEDUS are in agreement with those of other compatible SS software, such as FlowPc (Maloszewski and Zuber, 1996) BoxModel (Zoellmann and Aeschbach-Hertig, 2001), Tracer (Bayari, 2002) and Lumped (Ozyurt and Bayari, 2003). Unfortunately, to our knowledge, no publicly available hydrogeologic USLP modelling code exists in the literature to test the results of LUMPEDUS.…”

Section: Computer Code Used In Analysessupporting

confidence: 76%

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Steady‐ and unsteady‐state lumped parameter modelling of tritium and chlorofluorocarbons transport: hypothetical analyses and application to an alpine karst aquifer

Özyurt¹,

Bayarı²

2005

Hydrological Processes

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Abstract:Determination of a groundwater's mean residence time with the aid of environmental tracers is common in hydrogeology. Many of the lumped parameter (LP) applications used for this purpose have been based on steady-state models. However, the results may be misleading if a steady LP model is used to simulate the environmental tracer transport in an unsteady aquifer. To test this hypothesis, the results of steady and unsteady versions of several LP models were evaluated theoretically and in an alpine karst aquifer case by using tritium, oxygen-18 and chlorofluorocarbons (CFCs). The results reveal that the mean residence times obtained may be significantly different between the steady and unsteady versions of the same model. For the karst aquifer investigated, a serially connected exponential and a plug flow model were run under unsteady conditions. It is shown that outflux calibration with an unsteady model provides a firm basis in evaluating the results of models. An outflux-calibrated unsteady model predicted reasonably the observed series of water isotopes. The calibrated model's CFCs output overpredicts the observed concentrations, probably because of the time lag in the unsaturated zone of the alpine karst aquifer.

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Section: Computer Code Used In Analysessupporting

confidence: 76%

“…Details of serial and parallel combinations of LP models can be found in literature (e.g. Levenspiel, 1962Levenspiel, , 1999Ozyurt and Bayari, 2003). A dispersive SSLP model is given by Maloszewski and Zuber (1996) but to the knowledge of authors, no US version is available.…”

Section: Brief Theory Of Lp Modelling For Ss and Usmentioning

confidence: 99%

Steady‐ and unsteady‐state lumped parameter modelling of tritium and chlorofluorocarbons transport: hypothetical analyses and application to an alpine karst aquifer

Özyurt¹,

Bayarı²

2005

Hydrological Processes

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“…These models treat the aquifer system as a homogeneous compartment in which tracer input concentrations are converted to tracer output concentrations according to the system response function used and how the flow system is described (Zuber 1986;Maloszewski and Zuber 1982;Ozyurt and Bayari 2003). No detailed information, however, is needed regarding the flow system such as boundary conditions, porosity, hydraulic conductivity, which are necessary for numerical models based on Darcy's Law.…”

Section: Carbon-14mentioning

confidence: 99%

Mixing of shallow and deep groundwater as indicated by the chemistry and age of karstic springs

Toth

Katz

2006

Hydrogeol J

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Large karstic springs in east-central Florida, USA were studied using multi-tracer and geochemical modeling techniques to better understand groundwater flow paths and mixing of shallow and deep groundwater. Spring water types included Ca-HCO 3 (six), Na-Cl (four), and mixed (one). The evolution of water chemistry for Ca-HCO 3 spring waters was modeled by reactions of rainwater with soil organic matter, calcite, and dolomite under oxic conditions. The Na-Cl and mixed-type springs were modeled by reactions of either rainwater or Upper Floridan aquifer water with soil organic matter, calcite, and dolomite under oxic conditions and mixed with varying proportions of saline Lower Floridan aquifer water, which represented 4-53% of the total spring discharge. Multiple-tracer data-chlorofluorocarbon CFC-113, tritium ( 3 H), helium-3 ( 3 He trit ), sulfur hexafluoride (SF 6 )-for four Ca-HCO 3 spring waters were consistent with binary mixing curves representing water recharged during 1980 or 1990 mixing Résumé D'importantes sources karstiques du Centre-Est de la Floride aux USA, ontétéétudiées par multitraçage et par des techniques de modélisation géochimique, pour mieux comprendre les directions de l'écoulement souterrain et les mélanges entre les eaux souterraines phréatiques et profondes. Les eaux de source sont du type Ca-HCO 3 (six), Na-Cl (quatre), et mixte (une). L'évolution de la chimie des eaux du type Ca-HCO 3 aété modélisée par réactions entre l'eau de pluie et la matière organique des sols, la calcite et la dolomite, dans des conditions oxydantes, et par mélange avec des proportions variables de l'eau saline de l'aquifère du Bas-Floridien qui représente 4 a 53% du débit total de la source.Les Resumen Se estudiaron manantiales kársticos grandes en la parte centro-oriental de Florida, USA utilizando técnicas de modelizado geoquímico y multi-trazadores para un mejor entendimiento de trayectorias de flujo de agua subterránea y la mezcla de agua subterránea profunda y somera. Los tipos de agua de manantial incluyeron Ca-HCO 3 − (seis), Na-Cl (cuatro), y mezclada (una). Se modelizó la evolución de química de agua para las aguas de Hydrogeology Journal (2006) los manantiales Ca-HCO 3 − mediante las reacciones de agua de lluvia con la materia orgánica del suelo, calcita, y dolomita bajo condiciones anóxicas. Los manantiales con Na-Cl y mezclados se modelizaron mediante reacciones ya sea de agua de lluvia o agua del acuífero Floridano Superior con materia orgánica del suelo, calcita, y dolomita bajo condiciones anóxicas y mezclando con distintas proporciones de agua salada del acuífero Floridano Inferior, lo cual representó entre 4 y 53% de la descarga total de los manantiales. Los datos de trazadores múltiples [clorofluorcarbono CFC-113, tritio ( 3 H), helio-3 ( 3 He trit ), hexafluoruro de azufre (SF 6 )] para cuatro manantiales Ca-HCO 3 − fueron consistentes con curvas binarias de mezclado que representan agua recargada durante 1980 o 1990 que se mezcló con un componente más viejo libre de trazadores (reca...

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“…In earlier work on transit time using environmental tracers (Maloszewski and Zuber, 1982;Maloszewski et al, 1983;DeWalle et al, 1997;Ozyurt and Bayari, 2003), a number of idealized, hypothetical TTD functions using a steady-state assumption were employed to estimate MTT. The same or similar, time-invariant TTD functions were applied in unsteady-state (i.e., variable flow) cases for reproducing tracer concentration variations (Zuber, 1986) and for estimating temporally averaged MTT (Ozyurt and Bayari, 2005).…”

Section: Introductionmentioning

confidence: 99%

Temporal variability in mean transit time and transit time distributions assessed by a tracer-aided tank model of a meso-scale catchment

Yamanaka

2013

Hydrological Research Letters

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Abstract:The steady-state assumption for catchment transit time is a controversial issue in catchment hydrology. In this study, we propose a new approach to estimate the time-variant mean transit time (MTT) and transit time distribution (TTD) using a five-layer tank model with isotopic tracers and test it in the Fuefuki River catchment, central Japan. Model parameters were optimized during the calibration phase based on hydrometric and isotopic observations and then validated in a separate validation phase. The long-term (2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012) average MTT was estimated to be 23.7 years. However, the daily MTT was highly variable, ranging from 1.2 to 37.0 years. Instantaneous TTD also varied markedly. Precipitation alters TTD by increasing younger components and shortens the MTT. Thus, a steady-state assumption is inappropriate, with the relationship between monthly MTT and precipitation amount most closely approximated by an exponential function. The dependence of MTT on precipitation is an important descriptor for characterizing catchments. Although optimized model-parameters have some uncertainties, potential errors in estimating the MTT are relatively small (e.g., < ±3 years). Therefore, the tracer-aided tank model is useful for estimating time variations in MTT and TTD with high reliability.

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LUMPED: a Visual Basic code of lumped-parameter models for mean residence time analyses of groundwater systems

Cited by 35 publications

References 15 publications

Steady‐ and unsteady‐state lumped parameter modelling of tritium and chlorofluorocarbons transport: hypothetical analyses and application to an alpine karst aquifer

Steady‐ and unsteady‐state lumped parameter modelling of tritium and chlorofluorocarbons transport: hypothetical analyses and application to an alpine karst aquifer

Mixing of shallow and deep groundwater as indicated by the chemistry and age of karstic springs

Temporal variability in mean transit time and transit time distributions assessed by a tracer-aided tank model of a meso-scale catchment

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