An optimization approach for groundwater quality monitoring network design

Loáiciga, Hugo A.

doi:10.1029/wr025i008p01771

Cited by 142 publications

(113 citation statements)

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“…1 and 2) and the resulting difficulty in obtaining representative samples. The spatial sampling strategy thus has a strong impact on the result of any microbiological investigation of aquifers (Brockman and Murray 1997;Loaiciga et al 1992;Sievert et al 1999). Karst aquifer systems and other hydrogeological environments additionally show strong temporal variations, which require adapted temporal sampling strategies, e.g.…”

Section: Sampling Techniquesmentioning

confidence: 99%

Review: Microbial biocenoses in pristine aquifers and an assessment of investigative methods

2006

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The current knowledge of microbial biocenoses (communities) in pristine aquifers is presented in a review, which also discusses their relevance for questions of groundwater protection. Aquifers are heterogeneous on all scales and structured in a variety of habitats. The void spaces in many aquifers are small. The biocenoses are thus predominantly composed of microorganisms and, often, microinvertebrates. Larger voids and macroorganisms occur in karst cavities. Due to the absence of light, the biocenoses depend on chemical energy resources, which are, however, scarce in non-contaminated groundwater. The microorganisms thus show small cell sizes, low population densities and reduced activity; they developed specific strategies to survive oligotrophic conditions. The review also discusses the impact of contamination on the biocenoses, and the potential use of the biocenoses or specific organisms as indicators for groundwater quality, and the limits of this approach. Bacteria are either planktonic or attached to aquifer material, which requires both fluid and solid phase sampling. Most groundwater bacteria are viable but non-culturable. Consequently, cultivation techniques give an incomplete picture of the biocenoses, while methods from molecular microbiology provide genetic fingerprints of the entire community. Different analytical methods are available to count microorganisms, identify species, characterise microbial diversity, and measure activity.Résumé Cette revue expose l'état actuel des connaissances concernant les biocénoses microbiennes présentes dans les aquifères oligotrophes. L'impact d'une contamination sur les biocénoses est discuté, ainsi que le potentiel que Les bactéries sont planctoniques ou attachées aux matériaux de l'aquifère, ce qui demande unéchantillonnagè a la fois de l'eau et du substrat. De nombreuses méthodes sont aujourd'hui disponibles pour le comptage, l'identification et la caractérisation de la diversité, ainsi que la mesure des activités des organismes des aquifères. Comme la grande majorité des bactéries est viable mais non cultivable, les techniques de cultures actuelles ne donnent qu'une image incomplète des communautés, alors que les méthodes moléculaires développées récemment offrent la possibilité d'obtenir un profil de la communauté plus complet.Resumen Se presentauna reseña crítica del conocimiento actual de biocenosis microbiana (comunidades) en acuíferos prístinos la cual también discute su relevancia en términos de protección de aguas subterráneas. Los acuíferos son heterogéneos en todas las escalas y estructurados en una variedad de habitats. Los espacios vacíos en muchos acuíferos son pequeños. La biocenosis está por lo tanto compuesta predominantemente por microorganismos y, frecuentemente, microinvertebrados. Espacios más grandes y macroorganismos ocurren en cavidades kársticas. Debido a la ausencia de luz la biocenosis depende de recursos energéticos químicos los cuales, sin embargo, son escasos en agua subterránea no contaminada. Los microorganismos muestran...

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Section: Sampling Techniquesmentioning

confidence: 99%

Review: Microbial biocenoses in pristine aquifers and an assessment of investigative methods

2006

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“…Examples can be found in the work of Bras and Rodríguez-Iturbe (1976), Rouhani (1985), Loaiciga (1989), Rouhani and Hall (1988), Pardo-Igúzquiza (1998), van Groenigen et al (1999), van Groenigen and Stein (1998), and Nunes et al (2004a, b).…”

Section: Introductionmentioning

confidence: 99%

Optimal estuarine sediment monitoring network design with simulated annealing

Nunes

Caeiro²,

Cunha

et al. 2006

Journal of Environmental Management

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An objective function based on geostatistical variance reduction, constrained to the reproduction of the probability distribution functions of selected physical and chemical sediment variables, is applied to the selection of the best set of compliance monitoring stations in the Sado river estuary in Portugal. These stations were to be selected from a large set of sampling stations from a prior field campaign. Simulated annealing was chosen to solve the optimisation function model. Both the combinatorial problem structure and the resulting candidate sediment monitoring networks are discussed, and the optimal dimension and spatial distribution are proposed. An optimal network of sixty stations was obtained from an original 153-station sampling campaign. q

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“…As mentioned earlier, other objectives can drive the monitoring network design such as parameter estimation, model discrimination, and aquifer characterization. Figure 2 shows an augmented classification of the different objectives of monitoring networks, which builds around the classification given by Loaiciga et al (1992) for quality monitoring networks and extends it to include the other objectives discussed above. Classification of monitoring network objectives (or the purposes of having a monitoring well network).…”

Section: Review Of Monitoring Network Objectivesmentioning

confidence: 99%

“…As cited by Loaiciga et al (1992), Todd et al (1976) identified four objectives for groundwater quality monitoring activities: 1) ambient monitoring, 2) detection monitoring, 3) compliance monitoring, and 4) research monitoring. Ambient monitoring focuses on understanding the characteristics of regional groundwater quality variations over time.…”

Section: General Objectives Ofmentioning

confidence: 99%

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Long-term Monitoring Plan for the Shoal Underground Nuclear Test

Hassan¹

2005

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EXECUTIVE SUMMARYThe groundwater flow and radionuclide transport model characterizing the Shoal underground nuclear test has been accepted by the State of Nevada Division of Environmental Protection. According to the Federal Facility Agreement and Consent Order (FFACO) between the U.S. Department of Energy and the State of Nevada, the next steps in the closure process for the site are model validation (or postaudit), proof of concept, and long-term monitoring. This report addresses the development of the monitoring strategy for Shoal, which is needed for preparing the subsurface Corrective Action Decision Document/Corrective Action Plan (CADD/CAP). The proposed monitoring plan builds on three different, yet complementary, approaches (or tools) for locating the monitoring wells around the site with the main objective being detection monitoring and the secondary objective being data collection for model validation. The purpose of a detection-based monitoring system is the identification of groundwater contamination before a plume traverses a regulatory boundary located hydraulically downgradient of the contamination source. The design of such a system entails locating monitoring wells in the areas likely to encounter plume migration.The first tool is applied to select a number of potential siting horizons to which monitoring wells could be allocated. Based on plume geometry, this tool is used to determine the efficiency of each siting horizon and the minimum number of wells needed to span each horizon for detection monitoring. Different siting horizons can thus be ranked for detection efficiency by evaluating, for each horizon, the ratio of the maximum well spacing to the width of the potential zone of contaminant migration. A large value of this ratio indicates an effective horizon because the migration zone can be traversed with fewer wells. When a large number of monitoring wells are planned, a mathematical programming model that allocates a specified number of monitoring sites throughout the model domain can then be used. For Shoal, however, the number of monitoring wells is expected to be relatively small thereby allowing one to allocate the potential wells to the siting horizons with the highest efficiency rankings, provided that other constraints are being considered in this allocation process.Five siting horizons or control planes (CPs) have been selected for analysis. The five CPs are oriented perpendicular to the mean flow direction, which is not parallel to the model's y-coordinate. The selection of the location of these CPs is aimed at providing the necessary distances from the compliance boundary for a reaction time of 50 years. The farthest CP (CP #5) passes through the western edge of the maximum contaminant level (MCL)-based contaminant boundary (assumed here to be the compliance boundary). CP #4 is located at a distance equivalent to a 50-year reaction time (about 60 m) from the farthest point on the MCL boundary. CP #3 is at a distance of 60 m from CP #5. The next CP (CP #2) passes through the ea...

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An optimization approach for groundwater quality monitoring network design

Cited by 142 publications

References 22 publications

Review: Microbial biocenoses in pristine aquifers and an assessment of investigative methods

Review: Microbial biocenoses in pristine aquifers and an assessment of investigative methods

Optimal estuarine sediment monitoring network design with simulated annealing

Long-term Monitoring Plan for the Shoal Underground Nuclear Test

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