The design of hydraulic barriers: integration between rational and observational methods

Hydraulic barriers can be used to control and prevent the migration of pollutants from contaminated sites to the surrounding area. Their barrier design requires a deep knowledge of the geological, geotechnical and hydrogeological characteristics of the site. Data collection and hydrogeological modeling can be very expensive, especially in complex geological conditions. Furthermore, despite the significant amount of data to be collected and the economic resources engaged, the resulting conceptual model of the site might not result sufficiently detailed as to allow a reliable design of the barrier. An alternative approach is represented by the implementation of subsequent observational phases alternated to the actual design and construction phases, so that the barrier design results the optimum for the specific site under consideration. This integrated design methodology (rational and observational) is discussed in the article with reference to a major case study located in Sardinia (Italy).