The soil seed bank provides a reservoir of propagules to ensure species survival during unfavourable periods and is an important component of floodplain vegetation. However, little is known regarding the formation of soil seed banks and seed input is rarely quantified in seed bank investigations. Sources of seed include local seed rain and seed deposited wind, water (hydrochory) and animals (zoochory). We are presenting the first year of results from a study investigating seed deposition at the Chowilla Floodplain on the lower River Murray in South Australia in spring and summer 2017-18. Fifteen transects were established on Chowilla and Monoman creeks from the waters’ edge to 2 m above normal pool level; the seed bank was sampled and artificial turf seed traps deployed at 20 cm elevation intervals along each transect in October 2017. The seed traps were collected in February 2018 and the viable seed present in the seed bank and from the seed traps assessed using the seedling emergence technique. During this period, flow in the River Murray was generally low except for a small flow pulse peaking at 17,600 ML/day in early December 2017 raising water levels 40 cm above normal pool level. This allowed a comparison of the soil seed bank, seed deposited by hydrochory and by wind, animals and local seed rain. The seed bank was highly variable with a mean seed density of 5,700 seeds/m2 (ranging from 0 to 102,000 seeds/m2) with a total of 28 species. Mean seed deposition by hydrochory was 470 seeds/m2 (ranging from 0 to 1,475 seeds/m2) with 17 species. Mean non-hydrochory seed deposition was 1,067 seeds/m2 (ranging from 0 to 21,675 seeds/m2) with 31 species. Results showed potentially large numbers of seeds can be deposited on floodplains in a relatively short period.