Sigiriya water garden hydrostatic siphons: ancient pressure fountains and terracotta pipes?

The functional fountains in the symmetrical water gardens of Sigiriya operate entirely on natural gravity-fed hydrostatic pressure without mechanical pumps. Water channeled from the elevated Sigiriya reservoir was funneled through underground networks of high-fired terracotta pipes jointed with waterproof lime mortar. As the conduit sloped downward toward the lower garden lawns, the decreasing pipe diameter built up hydraulic pressure head. Water discharges upward through pierced circular limestone plates set inside sunken stone pools, producing natural water jets that still spray after monsoons.