Regional characterisation of hydraulic properties of rock using air-lift data

Hydrogeologic studies are commonly data-intense. In particular, estimations of hydraulic properties of hard rock often require large amounts of data. In many countries, large quantities of hydrogeologic data have been collect ed and archived over the years. Therefore, the use of existing data may pro vide a cost-efficient alternative to collecting new data in early stages of hydrogeologic studies, although the available data may be considered impre cise. Initially, however, the potential usefulness, i.e., the expected accu racy, of the available data in each specific case must be: carefully examin ed. This study investigates the possibilities of obtaining estimates of tra nsmissivity from hard-rock air-lift data in Sweden within an order of magni tude of results obtained from high-quality injection-test data. The expecte d accuracy of the results was examined analytically and by means of statist ical methods. The results were also evaluated by comparison with injection- test data. The results indicate that air-lift data produce estimates of tra nsmissivity within an order of magnitude compared to injection-test data in the studied examples. The study also shows that partial penetration and hy drofracturing may only affect the estimations approximately half an order o f magnitude. Thus, existing data may provide a cost-efficient alternative t o collection of new data in early stages of hydrogeologic studies.