Given the present and future changing climate and human changes to land use and river control, river sediment fluxes to coastal systems are changing and will continue to change in the future. To delineate these changes and their effects, it is increasingly important to document the fluxes of river-borne sediment discharged to the sea. Unfortunately, broad-scale river sediment monitoring programs established more than 50 years ago in the U.S. have diminished substantially and now focus principally on the largest rivers and estuaries. Unless addressed, these data gaps will provide significant challenges in addressing fundamental scientific and management questions about the effects of climate change and sea-level rise in our estuaries and on our coasts.