Mariotte Bottle‐Based Seepage Meter for Measuring Bidirectional Flow: Laboratory and Preliminary Field Tests

Abstract We developed a novel seepage meter incorporating a Mariotte bottle with a side opening that functions as an air inlet during losing conditions and a water outlet during gaining conditions. This design induces water level changes in both the Mariotte bottle and the collection pipe, enabling the estimation of downward and upward seepage rates, respectively. Laboratory experiments demonstrated a strong linear relationship between hydraulic head difference (Δ h ) and seepage rate ( R 2 = 0.996), consistent with Darcy's Law, and indicated that the device accurately measures seepage across a range of controlled conditions. Comparative testing against conventional collection‐bag methods showed close agreement, with no significant difference ( p > 0.05). Field tests in a coastal lagoon yielded seepage rates on the order of 10 −4 cm/s—about five times higher than previously reported, yet consistent in order and gaining conditions—demonstrating its potential as a promising alternative to existing seepage measurement methods.