Limestone aquifers are of great interest as a drinking water resource in many countries. They often have a complex crushed and fractured geology, which makes the analysis and description of flow and transport processes in such aquifers a challenging task. In this study, the solute transport behavior including fracture-matrix interaction in hydrogeological units of a limestone aquifer in eastern Denmark was characterized by designing, conducting and interpreting six depth-specific tracer tests involving natural- and forced-gradient conditions with multiple tracers representing different diffusion properties. To determine flow parameters, the tracer tests were complemented by a comprehensive set of depth-specific borehole and hydraulic tests.

Based on the tests, a new and stronger conceptual understanding was developed for the different aquifer units. The investigated limestone aquifer is composed of a glacially crushed unit and two fractured units, with calcarenitic and bryozoan limestone of similar hydraulic properties. Hydraulic tests revealed, that the crushed unit has a lower hydraulic conductivity than the fractured limestone units, likely due to the crushed conditions with small limestone clusters and small-aperture fractures potentially filled with fine material.

In the fractured limestone units, a distinct preferential flow and primary transport along major horizontal fractures was inferred from the tracer tests under forced-gradient conditions. The dominant horizontal fractures were identified on impeller flow logs and appear connected between wells, having an extent of up to several hundred meters. Connectivity between the aquifer units was investigated with a long-term pumping test and tracer tests, revealing restricted vertical flow and transport. A very pronounced hydraulic conductivity contrast between major fractures and matrix could also be inferred from the borehole and hydraulic tests, which is consistent with the findings from the tracer tests. However, the difference in the matrix diffusion behavior of the simultaneously injected tracers and a long tailing in the breakthrough curves revealed that matrix diffusion has a strong influence on the solute transport in the fractured limestone.

在许多国家中，石灰岩含水层作为饮用水资源备受关注。他们通常具有复杂的破碎和压裂地质，这使得对此类含水层中的流动和运输过程进行分析和描述是一项艰巨的任务。在这项研究中，通过设计，进行和解释涉及自然和强制梯度条件的六个深度特定示踪剂试验，设计，进行和解释了丹麦东部东部石灰岩含水层水文地质单元中的溶质运移行为，包括裂缝-基质相互作用，其特征是多个示踪剂代表不同扩散特性。为了确定流量参数，示踪剂测试辅以一整套针对特定深度的井眼和水力测试。

基于测试，针对不同的含水层单元开发了一种新的更强的概念性理解。所研究的石灰岩含水层由一个冰川破碎单元和两个破碎单元组成，钙钙质和苔藓类石灰石的水力特性相似。水力试验表明，压碎的单元的水力传导率比压裂的石灰石单元低，这可能是由于压碎条件下的石灰岩团簇较小，而小孔裂缝可能充满了细料。

在压裂的石灰岩单元中，根据强制梯度条件下的示踪剂测试可以推断出主要的水平裂缝有明显的优先流动和主要运移。在叶轮流量测井上发现了主要的水平裂缝，并在井之间连接，长达数百米。通过长期的抽水试验和示踪剂试验研究了含水层单元之间的连通性，发现竖向流动和运输受到限制。大裂缝和基体之间的水力传导率对比也可以从井眼和水力测试中推断出来，这与示踪剂测试的结果是一致的。然而，