Using water-level fluctuations in response to Earth-tide and barometric-pressure changes to measure the in-situ hydrogeological properties of an overburden aquifer in a coalfield

Shen, Qu; Zheming, Shi; Guangcai, Wang; Qingyu, Xu; Zejun, Zhu; Jiaqian, Han

Using water-level fluctuations in response to Earth-tide and barometric-pressure changes to measure the in-situ hydrogeological properties of an overburden aquifer in a coalfield | Utilisation des fluctuations de niveau piézométrique en réponse aux variations de la marée terrestre et de la pression barométrique pour mesurer les propriétés hydrogéologiques in-situ d’un aquifère de couverture dans un gisement de charbon Utilización de las fluctuaciones del nivel del agua en respuesta a los cambios de la marea terrestre y la presión barométrica para medir las propiedades hidrogeológicas in situ de un acuífero sobrecargado en un yacimiento de carbón 利用地球潮汐和气压变化引起的水位波动来估算煤田上覆含水层的原位水文地质参数 Usando variação no nível da água em resposta à maré terrestre e às mudanças de pressão barométrica para medir as propriedades hidrogeológicas in-situ de um aquífero suspenso em área de mineração de carvão

2020

For the quantitative evaluation of the impact of mining on a groundwater system, it is necessary to constrain the hydrogeological and mechanical properties. However, the in situ estimation of the mechanical properties of rock such as compressibility and porosity, is often difficult. Additionally, determining the hydraulic properties such as hydraulic conductivity, of rock by conventional methods is often expensive. The response of the groundwater level to external loading such as Earth tides and barometric pressure, couples the hydrogeological and mechanical processes of rocks, thus providing a way to infer these properties in the field. This study compared aquifer parameters inferred from tidal and barometric responses with those inferred from conventional hydraulic tests and rock mechanics tests in three groundwater monitoring wells at a site in China. The results show that the hydraulic conductivity inferred from a tidal response is similar to that of a pumping test. The compressibility values calculated for the three wells are all higher than those determined by experiment, and the porosity values calculated are all lower than those determined by experiment, but the differences between the calculated and experimentally measured values are lower than one order of magnitude. Considering the costs and convenience of the water-level response method, this method is a good choice for obtaining the properties of an aquifer, especially those in areas of tectonic activity and those affected by anthropogenic perturbations.

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