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Reliability, repeatability and accuracy of the falling head method for hydraulic conductivity measurements under laboratory conditions
- Pedescoll, Anna, Samsó, Roger, Romero, Enrique, Puigagut, Jaume, García, Joan
- Ecological engineering 2011 v.37 no.5 pp. 754-757
- constructed wetlands, hydraulic conductivity, subsurface flow
- The aim of this study was to verify under lab conditions the reliability, repeatability and accuracy of the falling head method (FHM) for hydraulic conductivity measurements. The FHM is a reliable procedure that has slight variations (less than 10%) in repeated measurements and turns out to be a reliable technique to record the hydraulic conductivities typically described for clogged and unclogged subsurface-flow constructed wetlands (from 4 to ca. 360m/day). The accuracy of the method is acceptable considering difficulties in the measurement of hydraulic conductivity in highly conductive media. Accordingly, results show measurement deviations of 20% when compared with a laboratory constant head method for highly conductive media (higher than 250m/day), and 80% for media with low hydraulic conductivity (lower than 50m/day). The main conclusion of the present paper is that of the FHM is a reliable and repeatable technique for hydraulic conductivity measurements and it is accurate enough for on-site clogging assessment in full-scale constructed wetlands.