Using Applied Tracer Tests to Predict Solute Transport in Fractured Rock Aquifers

Author: Douglas Weatherill

Weatherill, Douglas, 2013 Using Applied Tracer Tests to Predict Solute Transport in Fractured Rock Aquifers, Flinders University, School of the Environment

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Abstract

Applied tracer tests are used to measure solute transport characteristics of fractured rock aquifers. Whilst not always mentioned in the published literature, the ultimate purpose of the characterisation is to enable prediction of solute transport in the aquifer. The thesis examines the potential for using forced-gradient, applied tracer tests to predict solute transport under natural gradient conditions in fractured rock aquifers. Analysis of tracer tests to quantify aquifer parameters requires use of an interpretative model. Previously it has been assumed that equivalent single fracture and matrix parameters can be used to represent complex networks of fractures. Given the highly heterogeneous nature of fractured rock aquifers, tracer breakthrough curves often contain detailed features that cannot be fully replicated by comparatively simple analytical models. This thesis examines the parameter and prediction uncertainty that might arise from such discrepancies between fitted breakthrough curves and complex measured data. Comparisons are made between parameters and predictions obtained using different analytical models and the ability of single fracture models to interpret tracer transport in networks of fractures is examined. Methods to improve predictions of solute transport and quantify uncertainty are identified. Also, previously unidentified discretisation requirements are presented to enable accurate simulation of tracer transport in numerical groundwater flow and transport models.

Keywords: tracer,applied tracer,tracer test,solute transport,fractured rock,groundwater modelling,discretisation
Subject: Environmental Science thesis

Thesis type: Doctor of Philosophy
Completed: 2013
School: School of the Environment
Supervisor: Professor Craig Simmons