This study examines well-to-well tracer tests in crystalline rock aquifers in which the injected tracer is transported through a limited number of fracture channels even though many such channels may exist. The fractures that act as the significant paths of solute movement are termed transmissive fractures, and the location and properties of these fractures must be known for solute transport phenomena to be accurately analyzed. This study proposes semi-analytical solutions for tracer breakthrough curves at any depth in an observation well, at any point in time. These solutions were obtained from successive application of 2-D advective and dispersive transport models in the transmissive fractures, and 1-D diffusive transport model in the observation well. The solutions can be applied to locate the transmissive fracture along an observation well from tracer tests. Once the location of the transmissive fracture is known, the advective and dispersive characteristics of solute transport through the transmissive fracture can be estimated. A graphical method to determine the location of the transmissive fracture and to estimate the diffusive transport along an observation well is proposed. This method has been successfully applied to laboratory tests.

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