The researchers studied how waves transform in the surfzone and affect swash dynamics on two beaches in New Zealand. They found that the shape and energy of waves breaking near the shore greatly impact swash oscillations. Swash height varied with the tide, changing as waves broke over a sandbar. The swash height was higher when waves broke over the sandbar during low tide compared to high tide when waves barely broke. Swash oscillations were also different along the beach, influenced by changes in wave dissipation and beach slope. The study showed that wave breaking, tide, and beach slope all play a role in shaping swash dynamics on natural beaches.