Probabilistic sensitivity analysis for one-dimensional reactive transport in porous media

Journal Article · Mon Mar 01 00:00:00 EST 1993 · Water Resources Research; (United States)

DOI:https://doi.org/10.1029/92WR01948· OSTI ID:6378044

Cawlfield, J D; Wu, Mingchee ^[1]

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1. Univ. of Missouri, Rolla (United States)

A reliability approach for probabilistic modeling of reactive transport in porous media provides two important quantitative results: (1) an estimate of the probability that dimensionless concentration equals or exceeds some specified level and (2) a probabilistic sensitivity measure which quantifies the relative importance of each uncertain variable with respect to the probabilistic outcome. The approach is potentially attractive because it can provide both a probability estimate and probabilistic sensitivity measures; this is especially important for relatively low probability events where Monte Carlo simulation may require hundreds of thousands of realizations for reasonable results. The reliability method can incorporate marginal probability distribution functions (PDF) and correlation between uncertain variables, and the general method can be used with existing analytical or numerical solutions. However, a first-order reliability approach provides only an approximate probability measure; the accuracy is a function of performance criterion and statistical characteristics of the uncertain variables. The methodology and results here focus on probabilistic sensitivity measures which indicate the importance of any uncertain variable to the probabilistic outcome. In this work, one-dimensional reactive transport is investigated with the following uncertain variables: groundwater flow velocity, diffusion coefficient, dispersivity, distribution coefficient, porosity, and bulk density. We examine how probabilistic outcome and sensitivity are influenced by choice of marginal PDF, correlation, and magnitude of uncertainty for the variables. We also compare the probabilistic sensitivity results to typical deterministic sensitivity measures. Results indicate that the probabilistic outcome is most sensitive to likely changes in flow velocity and the reaction terms. 37 refs., 2 figs., 7 tabs.

• DOE Contract Number: FG02-89ER60828
• OSTI ID: 6378044
• Journal Information: Water Resources Research; (United States), Vol. 29:3; ISSN 0043-1397
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
ENVIRONMENTAL TRANSPORT
PROBABILISTIC ESTIMATION
STATISTICAL MODELS
FLOW MODELS
ACCURACY
SOILS
POROSITY
DATA COVARIANCES
DISTRIBUTION FUNCTIONS
GROUND WATER
INTERSTITIAL WATER
SENSITIVITY ANALYSIS
FUNCTIONS
HYDROGEN COMPOUNDS
MASS TRANSFER
MATHEMATICAL MODELS
OXYGEN COMPOUNDS
WATER
540220* - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)
990200 - Mathematics & Computers