Impact of permafrost development on groundwater flow patterns: a numerical study considering freezing cycles on a two-dimensional vertical cut through a generic river-plain system

Grenier, Christophe; Régnier, Damien; Mouche, Emmanuel; Benabderrahmane, Hakim; Costard, François; Davy, Ph.

Impact of permafrost development on groundwater flow patterns: a numerical study considering freezing cycles on a two-dimensional vertical cut through a generic river-plain system | Impact du développement du permafrost sur le mode d’écoulement de l’eau souterraine : une étude numérique considérant des cycles de gel sur une coupe verticale bi-dimensionnelle à travers un système type de plaine alluviale Impacto del desarrollo de permafrost sobre los patrones de flujo de agua subterránea: un estudio numérico considerando ciclos de congelamiento sobre un corte vertical bidimensional a través de un sistema genérico río - planicie 多年冻土的发育对地下水流模式的影响:一个考虑常见河流-平原系统中二维垂直冷冻的数值研究 Impacte do desenvolvimento do permafrost nos padrões de fluxo da água subterrânea: um estudo numérico considerando os ciclos de congelação num corte vertical bidimensional, através de um sistema genérico de planície de rio Permafrostsutbredning och dess betydelse för grundvattnets flödesmönster: en numerisk studie av en glacial cykel; utförd med hjälp ett två dimensionellt vertikalt tvärsnitt genom en generisk flodslätt med ett generiskt flodsystem

2013

The impact of glaciation cycles on groundwater flow was studied within the framework of nuclear waste storage in underground geological formations. The eastern section of the Paris Basin (a layered aquifer with impervious/pervious alternations) in France was considered for the last 120 ka. Cold periods corresponded with arid climates. The issue of talik development below water bodies was addressed. These unfrozen zones can maintain open pathways for aquifer recharge. Transient thermal evolution was simulated on a small-scale generic unit of the landscape including a “river” and “plain”. Coupled thermo-hydraulic modeling and simplified conductive heat transfer were considered for a broad range of scenarios. The results showed that when considering the current limited river dimensions and purely conductive heat transfer, taliks are expected to close within a few centuries. However, including coupled advection for flows from the river to the plain (probably pertinent for the eastern Paris Basin aquifer recharge zones) strongly delays talik closure (millennium scale). The impact on regional underground flows is expected to vary from a complete stop of recharge to a reduced recharge, corresponding to the talik zones. Consequences for future modeling approaches of the Paris Basin are discussed.

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