An analytical methodology to estimate the changes in fresh groundwater resources with sea-level rise and coastal erosion in strip-island unconfined aquifers: illustration with Savary Island, Canada

Chesnaux, R.; Marion, D.; Boumaiza, L.; Richard, S.; Walter, J.

An analytical methodology to estimate the changes in fresh groundwater resources with sea-level rise and coastal erosion in strip-island unconfined aquifers: illustration with Savary Island, Canada | Méthode analytique visant à estimer les changements des ressources d’eau douce souterraines liée à la montée du niveau de la mer et à l’érosion côtière dans les aquifères libres des îles étroites: illustration avec l’île de Savary, Canada Metodología analítica para estimar los cambios en los recursos hídricos subterráneos de agua dulce con la elevación del nivel del mar y la erosión en los acuíferos no confinados de la franja de islas costeras: un ejemplo en la isla de Savary (Canadá) 估算带状岛屿潜水含水层中随海平面上升和海岸侵蚀而引起的地下淡水资源变化的解析法:以加拿大Savary岛为例 Uma metodologia analítica para estimar as mudanças nos recursos de água doce subterrânea com a elevação do nível do mar e erosão costeira em aquíferos não confinados em faixa insular: exemplo da Ilha de Savary, Canadá

2021

Chesnaux, R. | Marion, D. | Boumaiza, L. | Richard, S. | Walter, J.

Closed-form analytical solutions for assessing the consequences of climate change on fresh groundwater oceanic island lenses have been developed by hydrogeologists during the last decade. Based on existing equations, this study focuses on the case of strip oceanic islands when three combined effects of climate change are observed to affect the freshwater lens volume and its groundwater resource renewal: sea-level rise, erosion, and change in groundwater recharge rates. New equations, integrating these combined effects of climate change on fresh groundwater resources are provided. These equations are solved by a novel methodology based on a Dupuit-Forchheimer groundwater flow model that allows for determination of the hydrogeological parameters included in the equations. The approach is illustrated with the strip island of Savary, which is located along the Pacific Coast of Canada in the province of British Columbia. This example illustrates, on the one hand, the volume depletion of the island freshwater lens and, on the other hand, the decrease of the renewal rate of groundwater. The proposed approach can be applied to any strip islands worldwide to assess the cumulative effects of sea-level rise and shore erosion on groundwater resources, depending on the predicted climate change scenarios. The results can then help decision-makers to anticipate the effects of climate change on the groundwater availability in strip oceanic islands and plan future groundwater use accordingly.

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