The karst permeability scale effect of Sete Lagoas, MG, Brazil

Autor(es)

Galvao, Paulo ^[1] ; Halihan, Todd ^[2] ; Hirata, Ricardo ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Geosci, Rua Lago 562, BR-05508080 Sao Paulo, SP - Brazil

^[2] Oklahoma State Univ, Boone Pickens Sch Geol, Noble Res Ctr 105, Stillwater, OK 74078 - USA

• Tipo de documento: Artigo de Revisão
• Fonte: Journal of Hydrology; v. 532, p. 149-162, JAN 2016.
• Citações Web of Science: 12

Resumo

Collecting and interpreting permeability data in karst systems is considered complicated due to three distinct properties of these systems. First, the distribution of high permeability features may be one-dimensional features difficult to detect with wells, or may be so high in the wells the upper measurement limit is encountered during aquifer testing. Secondly, turbulent flow may make the application of continuum hydraulic principles difficult. Finally, permeability in these systems commonly increases with the scale of measurement. The aquifer for Sete Lagoas, Brazil, was used to evaluate a permeability combination methodology testing the permeability structure across a range of spatial scales in order to develop a quantitative model of hydraulically active features consistent across all scales of measurement, from matrix properties to regional-scale flow. The aquifer in this study has some wells without measurable drawdown during pumping due to high permeability. Data indicated an increase in permeability from the small- to the well-scale and a decrease from the well-to regional-scale due to the localized development of a karst bedding plane dissolution in one structurally controlled region of the aquifer. The matrix permeability in the region is very low and the secondary porosity is mostly filled by secondary precipitation of calcite. Based on measurement technique, the permeability data vary over many orders of magnitude, while the physical size of permeable features of the aquifer are consistent across the scales of data collection. The geometry provides a quantitative understanding of the scale effects of permeability measurements. (C) 2015 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 12/12846-9 - Caracterização hidrogeológica e implantação de um modelo de gestão de recursos hídricos subterrâneos para aquíferos cársticos, no município de sete lagoas (mg)
• Beneficiário: Paulo Henrique Ferreira Galvão
• Modalidade de apoio: Bolsas no Brasil - Doutorado