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Effects of variations in hydrogeological parameters on water-table mounding in sandy loam and loamy sand soils beneath stormwater infiltration basins | Effets des variations des paramètres hydrogéologiques sur le cône de recharge d′un aquifère dans des sols sablo-limoneux et limono-sableux sous des bassins d′infiltration Efectos de las variaciones en los parámetros hidrogeológicos en domos de los niveles freáticos en suelos arenolimosos y limoarenosos debajo de las cuencas de infiltración de aguas pluviales 水文地质参数变化对暴雨入渗洼地地下伏砂壤土及壤砂土中地下水丘的影响 Efeitos das variações dos parâmetros hidrogeológicos na elevação do nível da água subterrânea em solos argilo-arenosos e areno-argilosos sob tempestades, em bacias de infiltração Texte intégral
2010
Thompson, Anita | Nimmer, Mike | Misra, Debasmita
The two-dimensional variably-saturated numerical model HYDRUS-2D, previously calibrated to recharge events from an infiltration basin, was used to predict water-table mounding under hypothetical basin design scenarios, and the primary factors that affect water-table mounding were evaluated. Infiltration basins are often utilized in urban environments to recharge stormwater to the aquifer. As a result of localized recharge beneath these basins, mound formation may reduce the thickness of the unsaturated zone available to filter pollutants and may reduce the infiltration rate of the basin. Understanding the effects of various physical factors on water-table mound formation is important for infiltration basin siting. For sandy loam and loamy sand subsurface materials, mound heights increased as the thickness of both the unsaturated and saturated zones decreased. Mound heights increased as the initial soil moisture, basin size and ponding depth increased. A thin sedimentation layer on the basin floor delayed mound formation, but only slightly decreased the maximum mound height. This analysis could be used in future selection of infiltration basin locations; however, the analysis is limited to conditions that represent only a select range of basin design conditions and parameters typical of a glacial till environment in Wisconsin, USA.
Afficher plus [+] Moins [-]Stepwise inversion of a groundwater flow model with multi-scale observation data | Inversion par étape d’un modèle d’écoulement d’eau souterraine avec des données d’observation à échelle multiple Inversión por etapas de un modelo de flujo de aguas subterráneas con datos de observación multiescala 利用多尺度监测数据对某地下水流模型进行逐步反演 Inversão passo-a-passo de um modelo de fluxo de água subterrânea com dados de observação multi-escala Texte intégral
2010
Dai, Zhenxue | Keating, Elizabeth | Gable, Carl | Levitt, Daniel | Heikoop, Jeff | Simmons, Ardyth
Based on the regional hydrogeology and the stratigraphy beneath the Los Alamos National Laboratory (LANL) site, New Mexico (USA), a site-scale groundwater model has been built with more than 20 stratified hydrofacies. A stepwise inverse method was developed to estimate permeabilities for these hydrofacies by coupling observation data from different sources and at various spatial scales including single-well test, multiple-well pumping test and regional aquifer monitoring data. Statistical analyses of outcrop permeability measurements and single-well test results were used to define the prior distributions of the parameters. These distributions were used to define the parameter initial values and the lower and upper bounds for inverse modeling. A number of inverse modeling steps were performed including the use of drawdown data from the pump tests at two wells (PM-2 and PM-4) separately, and a joint inversion coupling PM-2 and PM-4 pump test data and head data from regional aquifer monitoring. Parameter sensitivity coefficients for different data sets were computed to analyze if the model parameters can be estimated accurately with the data provided at different steps. The joint inversion offers a reasonable fit to all data sets. The uncertainty of estimated parameters for the hydrofacies is addressed with the parameter confidence intervals.
Afficher plus [+] Moins [-]Groundwater source assessment program for the state of Hawaii, USA: methodology and example application | Programme d’évaluation de la ressource en eau souterraine pour l’état de Hawaï, USA: Méthodologie et exemple d’application Grundwasserbeurteilungsprogramm für Hawaii, USA: Methoden und Beispielanwendung Programa de evaluación de aguas subterráneas para el estado de Hawaii, EEUU: Metodología y ejemplo de aplicación 美国夏威夷地下水源评价程序 : 方法和实例应用 Programa de avaliação das origens de água subterrânea para o estado do Hawaii, EUA: Metodologia e exemplo de aplicação Texte intégral
2010
Whittier, Robert B. | Rotzoll, Kolja | Dhal, Sushant | El-Kadi, Aly I. | Ray, Chittaranjan | Chang, Daniel
The 1996 reauthorization of the Safe Drinking Water Act required that each state in the US addresses the protection of public drinking water sources, including the development and implementation of a source-water assessment program. Such a program includes delineating source-water assessment areas, inventorying potential contaminant sources within this area, and determining the water system's susceptibility to contamination. The public was also involved in various phases of the program. Hawaii’s groundwater source assessment program is presented, along with an approach for implementation, which is consistent with federal requirements. The approach integrates groundwater models, aquifer databases, and a geographic information system. Source assessment areas were delineated by using numerical groundwater-flow models that used site-specific data to their fullest availability. The proposed approach is flexible enough to allow easy future updates as more sources are identified or as new information becomes available. The final product includes numerical scores that quantify the relative source susceptibility to contamination. Aquifer models developed in this study are potentially useful for future site-specific protection efforts or for other modeling purposes.
Afficher plus [+] Moins [-]Enhanced groundwater vulnerability assessment in geological homogeneous areas: a case study from the Argentine Pampas | Détermination améliorée de la vulnérabilité de l’eau souterraine dans des domaines géologiques homogènes: une étude de cas des Pampas d’Argentine Evaluación optimizada de la vulnerabilidad de aguas subterráneas en área geológicas homogénes: un caso de estudio de las Pampas de Argentina 均质地区增强型地下水脆弱性评价: 以阿根廷Pampas地区为例 Melhoria da avaliação da vulnerabilidade da água subterrânea em áreas geológicas homogéneas: um estudo de caso nas Pampas Argentinas Texte intégral
2010
Massone, Héctor | Quiroz Londoño, Mauricio | Martínez, Daniel
The southeast area of the Argentine Pampas is characterized by the presence of an unconfined aquifer in a wide plain. A methodology is proposed that deals with the aquifer vulnerability where the homogeneity of the hydrogeological variables used by traditional methods (in this case, DRASTIC-P) causes vulnerability maps to show more than 80% of the territory under the same class. This absence of discrimination renders vulnerability maps of little use to decision-makers. In addition, the proposed methodology avoids the traditional vague classification (high, low, and moderate vulnerability) which is highly dependent on subjectivity in its association of each class with hydrogeological considerations. That traditional vulnerability assessment methodology was adapted using a geographic information system to reclassify classes, based on the Natural Breaks (Jenks) method. The pixel-to-pixel comparison between the result obtained by the DRASTIC-P and the reclassified classes generates the so-called operational vulnerability index (OVI), which shows four classes, associating each with different hydrogeological requirements to make decisions.
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