Effects of aquifer geometry on seawater intrusion in annulus segment island aquifers

Abstract. Seawater intrusion in island aquifers was considered analytically, specifically for annulus segment (ASAs), i.e., that (in plan) have the shape of an segment. Based on Ghijben–Herzberg and hillslope-storage Boussinesq equations, analytical solutions were derived steady-state seawater ASAs, with a focus freshwater–seawater interface its corresponding watertable elevation. Predictions compared well experimental data, so they employed to investigate effects aquifer geometry aquifers. Three different ASA geometries compared: convergent (smaller side is facing lagoon, larger internal no-flow boundary flow converges towards lagoon), rectangular divergent boundary, sea diverges sea). Depending geometry, found vary greatly, such assumption model can lead poor estimates intrusion. Other factors being equal, aquifers, more extensive, elevation lower opposite tendency Sensitivity analysis further indicated width distance from circle center inner arc (the lagoon or aquifers). A weaken hence differences predictions three become less pronounced.