Permafrost thaw is a complex process resulting from interactions between the atmosphere, soil, water and vegetation. Although advective heat transport by groundwater at depth likely plays a significant role in permafrost dynamics at many sites, there is lack of direct measurements of groundwater flow patterns and fluxes in such cold-region environments. Here, the finite volume point dilution method (FVPDM) is used to measure in-situ groundwater fluxes in two sandy aquifers in the discontinuous permafrost zone, within a small watershed near Umiujaq, Nunavik (Quebec), Canada. The FVPDM theory is first reviewed, then results from four FVPDM tests are presented: one test in a shallow supra-permafrost aquifer, and three in a deeper subpermafrost aquifer. Apparent Darcy fluxes derived from the FVPDM tests varied from 0.5 × 10⁻⁵ to 1.0 × 10⁻⁵ m/s, implying that advective heat transport from groundwater flow could be contributing to rapid permafrost thaw at this site. In providing estimates of the Darcy fluxes at the local scale of the well screens, the approach offers more accurate and direct measurements over indirect estimates using Darcy’s law. The tests show that this method can be successfully used in remote areas and with limited resources. Recommendations for optimizing the test protocol are proposed.

多年冻土融化是一个复杂的过程，是由大气，土壤，水和植被之间的相互作用导致的。尽管在许多地方，地下水对流的热传递可能在多年冻土动力学中发挥重要作用，但在这种寒冷地区环境中，缺乏直接测量地下水流型和通量的方法。在这里，使用有限体积点稀释法（FVPDM）来测量加拿大努纳维克（魁北克）Umiujaq附近一个小流域中的不连续多年冻土带中两个含砂含水层中的地下水流。首先回顾了FVPDM理论，然后介绍了四项FVPDM测试的结果：一项是在浅层超多年冻土层中的测试，另一项是在深层多年冻土层中的测试。从FVPDM测试得出的视在达西通量在0.5×10 ^{-5范围内变化}速度为1.0×10 ^-5  m / s，这意味着来自地下水流的对流热传输可能会导致该地点的快速冻土融化。在提供井网局部尺度上的达西通量估算值时，与使用达西定律的间接估算值相比，该方法可提供更准确，更直接的测量结果。测试表明，该方法可以在偏远地区且资源有限的情况下成功使用。提出了优化测试协议的建议。