MASS RECOVERY DURING TRACER TESTS IN FRACTURED AQUIFERS AS ESTIMATED FROM MULTIPLE WELL HYDRAULIC TESTS

A technique is developed to use hydraulic tests in two or more wells in fractured rock to predict mass recovery during forced gradient tracer tests. Flow is considered to take place through a number of conduits, which connect the wells to each other and also to distant sources or sinks. The mass recovery is related to the proportion of flow in the pumping well that is derived from the injection well. The method is applied successfully to several field-scale tracer tests in fractured aquifers in the Clare Valley, South Australia. The technique can be used to choose well pairs for tracer tests and which direction to establish the hydraulic gradient to maximize mass recovery for convergent tests.